Detailed contents
TopiC 6
Metals
95
Sub-topic I C.enera.t properties of mda.ls _ ... _~
Sub-lOpic 2 Reactivity and the dectrochemkal ~ril."'i
SU1HOI'1c 3 Alloys
Sub-IOI,it" 4 (~Ion
Surnm:lry
Re<.'ision ('"erd~
Assessment ('''c~
,
SUb-topiC 1
Sub-wpic 2
Sub-topic 3
Sub-topic i
Sub-topic 5
--
Coener.Jl propE'ttles of non-Illl"tah
Il}'"drogen
Ox}'Xffi
Nitrogm
Carbon and ~tes
%
98
103
105
107
~i~ l'xe,cisn
Asse\YIlO'flt ('xen:ise;
•
•
,
,
•
,
•
122
•
•
•
Coo I o:>&ioI,
'"
162
""
168
176
177
".
,
1
•
,
• 1
•
12'>
141
156
I
• I
• 1
'0
139
SUnlTllaJ')'
-
0'
07
Topic 8
Saturattd and unS:lluratoo h}'drocarbons
HomologQUs Sol'ries
AlcoholS (alka/lo!sj
Carboxylic acids (alkanoic adds)
£SIers ('1lkaUO<Iles)
MacromolC"ClJles (polymers)
•
•
,.
RevIsion v;e!tiws
Assf5smcnl n:~
Sub-topic I
SUb-t0l'k 2
SutHuI'IC 3
Sub-t"l'k 4
Sub-topic S
Sub-topic 6
•
108
108
136
137
138
OrganIc chemistry
•
-.L...'
Starter activtty
AIlsw... tl~ fOI~~
then diSC"uss as a
I. l~tM" whe:,,~, tIIi
tht·l'l'rlodicTab
2. USI some uf the III
at home and diSC'll
metal was u'K'd to
3. Gl\"l' a f('ason wll)
uS('d In a thl'tlIlOll
aluminium me-..al
-
-I. Name'
5OTJll>
factor
t~ ~ 01. roppr
copper ~ out at
and ttw doIIM pr:il
94
Metals
96
98
>03
Geo.....
pIllp81ies of
.• 00
series
• Demonstrate an order of 1UaC1Mty.
.
• Des: ibe the eftects of heat on hydroJcides, carbonate$,
nitrates of metals and III' .'lOllium compcunds.
• 0
i ibe the 8Xti aetiol, 01 ooppeo, mn and ~ Irom their
• ibe ~ r1!pn!S1!l'1tat gf I)Ule melab.
title the ph)3ieal properties 01 metals.
metals
• Describe Itle cte,lical properties 01 me&aIs.
ReactMty and the • 0
·ibe Ihe reac:tMly series of metals.
e'8 bochemic:al
• Explain the lIIPP\1IellI ~ 01 ak.minium.
'OS
>0,
'OS
'OS
~
• Describe the uses 01 QOPPeO". iron, zinc and aluminium.
• Explain the harmful effects of some metals.
0,'
Describe allays.
DesQibe diagranvnatic rapreseotatioos of alloys.
Explain the advantages of using a1~ over pu:lI metals.
Identify cornmon uses of alloys.
'"
'"
'22
113
• Describe COfI'OSion.
• Relate cOlTOsloo 10 the ,eactivity of metals.
• Describe dlfterool mtlthods of preventing COITosion.
'"
036
m
'38
'"
'56
,,.
'62
,.,
'68
076
111
,,.
Starter activity
AIls""'" til., follo'~illg questions In pairs, and
Ihffl di~"" as a d.;lss:
I. I~bo- wrn.-re Ihe mtlills are located on
Illl' f'niodj(" Imle.
2. l.is!: some of the mf'taJ ob~ you han"
al IKnnc.> and d&uss why you thlnt
mnal was used to maU each objKt.
3. GhT a l'l'a:lOfl why tlM' meuI mm:ury is
ll'nl in a ~et md wily
aluminium metal is USoN for moldrin\;
~
4. KaIIX' wme f<><:tors !hilt can IntllK't1O'
thl' prke of copper. (Hint: Consider all 1M 5te'p'i in'"Oh..-d from getting 1hC'
C"op(l'er ore out of
ground 10 pl'OC15Sing it, the intemalkmal d@mand
and thE' dollu pl'ia.)
w
SUB-TOPIC 1
General properties of
metals
Over 8O'I'l> of the ~l"IDI'TIU in rhl' lTrioc!lc Table
rnttm. Th")' ~ <:ill~riscdiIS Ihfo alblJ
mnals, 1m, alblinr ~als and 1M tnnsition
t'lemcnls..
In Gr~ 10, ~ ~amllhal a\orns of metals
ha~"" a -se. of ~Ioalizrd cl<'ctrons· which mQ'\"l!'
about ~y mlOIlS tbf: mt'taJ. atoms. ~
driocaliud I'lKtrons an" n-spom.i~ f(lf lNny of
tM chmllal and ph}'5k:;Ll prope'ltif'5 01 mMals..
Remember
art'
The oonizalion elagies af
metaI:s are
otA ....... &d to the
olI.lS, andtt.e.....
>ey lillie eroergy is needed to
H
5! their ,aIeolOll
Chemical pr
During ....m-miQ.! nttndtrKy to ool1.3tt ,
1. Reaction of n
\lnals rean "i1h or
tuns wi:t'l.
Mg
white~
t't b.....
K
.....burns vig:a;
2. Reaction of ..
Representations of pure metals
ThO' mrtalllc laulU" consUts of >om surroundf'd by thl' dd<x,t.liud I'IKtrons. 1hest'
flff t'lKtrons act as an -electmnk glUI!'" ....hlch hol<b the atoms togl'too. A
m~allk bond is formed by th....I«troslatk fOIC'l' bctWa-II the dekxalized
el«(roM (nO?gati\'e) and th.. c"liom
(posltlvt». The strength of th..
metallic bond depends on the nz...
uf the lnNal's atomic radius and the
nlllntX'r of valence elertrons that
have
~11
deJocalizoo.
Figure 1 A representation of a pure metal
~ltUls It'aCt
with "'....
Mg
hot water te
K
coklwa:er
reaction 1$ ,
3. Reaction of n
~ietals
Mg
,<'an with diJ;
dilute hydn:
acid (vigen:
Physical properties of metals
Metals us~l1y haw thl' following physkal properties;
• Tht')' are shiny when potWin!.
• They ~rt' sonorous (tbey mal:<> ~
rlnging sound wilen they Hf'
stl\ld.:).
• They ~rt' ~~bk- {they c:m IX'
holl1Unffed into !Ju.pe wi!bout
bre~king apart).
• They Me ductilt- (thq- c:m IX'
dawn out into wires).
fIgIn 2 Gold is a typical metal: it is
• they "Il! load rooductoo of beat ~ lII'ld remains unchanged lot
mel el«tooty.
many ~ This is one of the main ,-_•••••
it Is used ., jeweIlefy.
• They rn.~ high ~11in8 poilus
and high boiling points (they lift'
~"soIkbH room IUIll't'''IUft', n:cq?f for mf«Ufy).
• Many mttaIs lift quitt dtnst, Iurd lIIId tough. but thtrt lIrt 5OI1It txetptions..
96
·"opic' ~
Fe
dilute hydn:
'l,-C"C~ acid (V'lIfY'
~. 1)iJut<
")'droxhlan<
b)'dro!:<"> is <»:idi.>!d to ..
4. Reaction of
A mort Il'anivt
[j
mt!I
Ans...-n thr quntloo
tquat>ons for 1mI. zin.. mel dilut.. l
z. ..aJctum and "-al
=
Chemical properties of metals
-" .
,.edtolhe
"""'~
.ededto
During a dlpmi<;al reaction of a Illt'!al with other compound~, tIll.' metall1as the
WIld,·ncy to <lonate elKlrons to form a positive ion.
1. Reaction of metals with oxygen
:-Ietab react willl oxygen to J''''don' na'tal oxi<lt'S.
Mg
ooms with a brilliant
white flame
magnesium oxide
2Mg (s) • 0o(g) -. 2MgO(s)
K
burns vigorously with
a purple/lilac flame
potassium oxide
4K (s) .. 02 (g) ---'> 21\.0 (s)
2. Reaction of metals with water
).,Ietals {('art with water to fOfm metal hydIOxld", or oxid"', and hydrogen gas.
:o«trom. nwse
~.A
-'
, .. pure metal
..-t;ilis
¥dfor
_ main reasons
• e'Xc<:ptions.
Mg
hot waler (only)
Mg(s) .. 11,0(1) ..... MgO(s) .. H,(g)
_+,'""d=""Yod=rog",oo",g"~=c-t.oc
potassium hydroxide 2K(s). 2H,O (I) -, 2KOH (aq) .. I-I,(g)
and hydrogen g'~'-_L__
1-;0--1
K
magnesium oxide
cold water (the
_--"reaction is vio~l)
3. Reaction of metals with dilute acids
~·letal<
M9
react with dilule acids 10 form saliS and hy<!w!:(,ll.
d,I\lIO hydrochlonc
!;-;:-_Eacid (vigorously)
dilllle hydrochloric
b~Jacid (very slowly)
,
magnesoum chlolide Mg (s) + 2HCI(aq) .... MgCl (aq) + H, (g)
2
and hydrogen gas
ironQI) chloride and
hydrogen gas
Fe(s) + 2HCI (aq) ---> FeCI (aq) +
2
"' t~lut. hyd"xhloric OJ rulphurk" >oei<:l' con I>< "..-d. I>u' no' "Iuk" .cld. \\1'h "Ihk ...·Id. ll~
'tlrog.n I> oxlili70<! ", .....,.
4. Reaction of metals with metal salt solutions
A. mOT<' "oactiv<· metal displa<'<-os a I"", J'<'an;ye metal from a solution of ils saIl.
copper from a copper Mg{s) + CuSO. (aq) .... MgSO. (aq) + Cu (s)
'Io;:-_+',:,ul:phaIO solution
Fe
copper from a copper Fe (s) .. CuSO4 (aq) .... FoSO. (aq) + Cu (s)
sulphate solution
~ Properties of metals
Answer the questions that follow on YOut own. W,ite balance<! chemical
equations for the reactions betw""n:
1. zinc and dilute hydrochloric acid
2. ~'alcium and wal"r
:1. copper and oxygen
H~(g)
SUB-TOPIC 2
Reactivity and the
electrochemical series
A rl'X1i~"t" ~mm.t Is Oft(' th.lt "'act.\ easil)' with OIhcr .. lmHnts or <U01pounds $0
th<lt Its atOlD.'O @In slabit' (lillt'd) nut....- shrils. MMal. In t~ numbc=d groups in
IlK' ~Tabk' hi\,. \ ~ Iml are tM loOIJllf' illS Ihfo ~p nurnlx't", but IIw
transition IIl<'tah mo,,. '~hk
,,,k-ncWs.
l,Exparim
Materials
rou ..ill nffd:
• 2 .. Its! 1Ube\
The reactivrty series of metals
The Old..... of reactivity uf lIl('lals nn IX" d<'1{'nnint"d by stud)'ing n-anionS of
metals in the lahoralory with oxygen, waIN, dilul(' adds, and aqUl'OUS solutiom of
metal sallS. Th", reactivity SC'ries is til{' arrangernrl\1 of 1Ilt-lals in order from Ill.. '
least ,{'atii"," to tlw most r('artl'·... TIl<: more
New words
r{'acti,'" the m{'lal is, lIlt' <'a,IN It is for it to form
Us nmlpound,. and lilt' hard..., It is to breal.:
down its compounds. 'nIl' reactivity seri... hdps
us 10 p"..t.Ikt how metals might ",a<1.
I
_._.__._
_._.._ ..••._
_
_ _
reactiYity series: an ordeIed bl 01
shows whicI'l mel:lIls
........ or Ie$S ~ \har'l
~
_
the_
- -- - -./
./
./
x
x
x
x
8. Iloklle<1 ~
ot:>sl"n'3lions ..
./
./
./
./
./
Obs<er\'arioos
I. Complf'le tht-
./
./
~
-_./
x
2. hOm your nOC
oa'Urf<'tl, and
Fogu'll 3 The reactivity:ieries of metals
Exception to the rule: Aluminium
The ~lion of a1rnnlnium in the ~ivlly
WTl... Implit'S thai il should ~ quile "'arti,~.
lIow.·'...·" it dot'5 no! rt"~ with;o<.ids and it is
rt':S!slanl 10 CtJnmk>n h«;I~ of 1M ~ of
a Ihln C'Oi.t1ng of aluminium oxidP (AI,Osl 0"'""
liS wtfa<Y. ih.i. oxi& is unr..;ont\... and pro!l'('1\
lhe.' aluminirnn brio... ils \Utf~.
98
1.."..,. ~_
filings
• I .. 'l);Itula of
COPIIN(ll) OX~
• I .. spatula of
magll~lum 0
1. MunIIOI~'C
f11J1U' lmd pUil
.T
./
./
test lubr hoIdes'
test Iubl' r.Kk
6uII:;en burne:
2 .. spatulas of
6. Ught the Ek..-:J!
O\"t'IIMo f1Ir.M
""7""
x
x
x
x
x
x
x
x
x
x
•
•
•
•
Old you know?
•
AUnnum is also an e>«:eptioo,
COoellUion
to lhe octellVle. Most alOIM bY
I. Write a baIa."X'
\Q ~ or \o$e ,
2. Whi('h three "
~oOlS during
btwO'll \Q end up wIlh a stable
eighI YaI e ~ elect10ilS, bul
............. makes <MY SUbIe
cornpcu1ds wi!h onty sill
vaIercIt elect10i ..
3. Wrile thr th.'ft'
4. If Iht- exprrlml
...hat do rou ::
"....)
TOPIC
_ _ Reactivity order
Carry oUi this '>'T,,>rimeot in groups of four.
..ounds so
_poup,in
~ but the
1I:DOn' of
. . - )Oluli"n, of
nom lhe
-
): Experiment ~..'1
Materials
'·on will n~d:
• 2 x test tUM
• test tube hOlder
• tesl tubt' t;1\"k
• Runsen burner
• 2 x spatulas of iron
f,lings
• I x spatula of
<"opper(I1) oxide
• 1 x spatula of
magnesium oxide
•
Aim
j To ddermille an
order of ..,a'1hily in mrrab
Procedure
1. Labt'J your test tubes A and B and put them in the
t~t tub•.' holder
2. PI,,,·e one spatula of iron filings in "aeh t"SI tubt'o
3. In lest tub<' A, add on" spatula of COpP"T(IlJ oxide
and .lWntly mix it Into the iron filings.
4. In I~t tuhe B, add on" spalu;a of magn<.>sium
oxide and gocntly mix it into thoc Iron fdings.
5. Copy the tahk und"r ·Observations· (\){'Iowj into
your notehook, and rompl"te the first "ntry for
,.....
hoth t<'St IUbes_
6. l.ighl til{' Bunsen burner and hold lest tube A (using til{' t"st tu\){' hold"f)
o'-er the flame for a minute or two. 'Vrite down your ohse"-ations.
7. Monitor any changes in appearance in test tub<' A as rou take it off the
flame and pla,'e it back into the t<'\t lUhl' rack.
K. Ilokl test lubl.· B over th,· flame for a minUle or IWO, write down your
onscrvalions and pla,·e the teSl IUlx' ha,·k into Ihe l<':It lUbe tack.
Obsf'rvatioIU
I. ('",mplete th"tabl,,:
Test tube A
-I"T.est tube B
2. From yonr nOles in the table, determine in which lest tuhc a reaction
occurred, and give a reaSon for your answer.
Conc:lusion
. . exception
_. ""'
Yost: aloms try
during
wttn a stable
oWdl:"'"
~stab'"
,",,"
I. Writl.' a balancl.od I."<jua!iou for Ihe r"action that look pIa,"".
2. Whi,·h tlm"I.' metals we,I.· uS<."d in Ihis nperiment?
3, Wrile til<" lluff metals in order of reacthity, from least reactive to mosl reactiw'.
4. If the experim<"nl is re~ated, but using mI<· oxide and lead oxide instead,
what do you lhink would happ<>n 7 (llinl: Refer to Hl';Ulr] on the pI1"\·;ous
page.)
Sub·topic 2 K<o< tivity and the .1.,..,wcheo>kll1 _
99
Effect of heat on some compounds
Copper
Ill'al ('llll blt'ak down Cl'rtain rump"und~ qult('
l'Milr. This P'(I{('5S is l;nnwn "" thermal
d('C()rt\position. ltown...., compounds lhal
CoppI'r is l"ll:lractel
sulphidl"s, \llka:rl;
ronUIJI ml"tals that ilR' highn" up on lho:-
.-
Thl" extraction me
typl.' of OR'. ~ 01
br.dI '" doom "'. c:ompolII"Id_
A'JoCthlily 5t'lks (in <>too ...'Ol<h. th<lo5l" lhal a...
mon' tt'X'tn"t'I, art' ~ stabIl' than lJthcoa and 5(>
(Jo:, noc drrom(lOW' as NSily ",hffi bl'aII'l1, 1'h<' uhW below sno.."S SODll' t'XiUllpM5.
--
NaOH
no efIec:t
no eflect
~
decompo
~
dBc:oo'OPO MloZnO(s)and~O(ll
'.x :es 10CuO(~and~O\l)
KOH
.,....,.
"'lro<h ..
mloMgO(sland~O(l)
="""'"
"';~'&-_~_~
~CO,
N""C03
MgCO.
znco.
CoCO.
Nitrates
KNO~
NaNO
Mg(N6}.
Zn(NO}.
_ _JCCu{NO}.
(IJI lambia '" ,,"'I
Chalrop)'rill', but I
For tJm ..--xl. :b
Thl" atl3ction is a
Stq t 1hl" OR' il.
1
no effect
no eflect
("()(II'" Is Cl
St~gt"
OOC:Qo'OPO 50s to MgO(s) and CO.(g)
de<;:Qmposes 10 ZnO (s) and CO. (g)
decomposes to CuO (s) and CO. (g)
°
partially decomposes 10 KNO~(s} and
(g)
partially decomposes to NaNO,(s) and
(g)
decomposes 10 MgO(s), NO. (g) and 0. (g)
easily decomposes 10 znO{s), NO. (g) and 0, (g)
easily decomposes 10 CuO(s), OO.(g) and O~(g)
6,
Although Ihl.")' do not {'(Iolain nK'lals, ammonium sailS shO¥.' a similaI !tend In
t1."a.c'\iv,ly whl"n hl"atl'l! 10 wry high l('lfipl"ratun'S, Fo. l"xampll':
• Ammonium chklI;dt':
NII.Cl (S) ... Nli (g) • !lCI (g)
l
• Ammonium rulphall':
("'11~)?,-). (s) ...
• Ammonium nitron...,
NIl~KOI
(s) •
Np (tl • ZH!O(g)
Ml'tals O«(Ur nalural.ly in lhe form of om, whkh ilR' a mixtuR' of lhe ~a1llsclf
(1UW1ly in Ihl" form of an o:ddl", (':Irbonall" or $Ulphidl'1 and impurit~ 1lIl'
prtI(("Ss oj Illt'la.ll"ll:lrartion imvt\'n laling IhI" ~ frum tM l'arth UK!. ~Iing rid
of Ihl" intpurilil's unlil a pun" rnl'1a.1 rl"mains.
Metall"XUX'tioon ~ on 1M l\'IIICti'ity of Ihf' mt1.al in lhl' <Ill'. Soml' IIll"tals can
bf' I"Xlr;l(1:00 by rOOucing the Oft" "~Ih <'arbo>l, OIrbon lIlCJnOXido' <II h)'droRm, Oth=
cannot IX' rt'du«d in this w.ay, and Ih<'r('for(' haw 10 """ l":<lIa<1N b)' ril'ctroIysIs.
<lir;
2CuF"S.1l
Slag<' l AdditiOn.a.
't'hl" result
Iron
!fon Oll" (0< hal::m.
.and olhl"l mlnl'r.al
deriwd snuKl' of I
which is.a th.~'\l
Stage I 111l' roll' I
Stag<" 211ll" ~'arlIOI
<":(5) + CO
Stag<"
Nil, II) • tl;>o~ (g)
Extraction of metals
T<>pk6 M<U!>
2111l' ('(mal
silicon
Thermal decomposition of ammonium salts
100
un....antft!
1M W"'·, ~
3 TIll' nrbol
Fl"}IJN4
1'h<"~kp'
oubon ltioxldcl...~
iron ;It lhl' botlom
l'he liquid imn
Zinc
ZJn<, is l"XIlXtnl 11
both ha''l' to bl' ClI
II is bumlln I
OR".
rn.,n n'du«<.llo Col
10 zin... alld Iill" l7'
-
Copper
Copper is cxtra<;too from ore:; thai may ("ontain
sulphides, silkau:s, <:artxmalCS or sulphat~.
TI,,:'
,n'.'lhod dillers dqX'tlding nn the
tYl"" of "'\'. One of the most common ("(>PP"" OJ'<'!;
(in :r.ambia as well) is a sulphid<.> ore, <:alkd
chalcopyrite, hut it contaim If'SS than 1% '~'pp<-r_
for thiS wason, the ow must tirst h(' ooncemrat<'d.
('xl,,,,'i,,,,
TIll.' exlTat1ion is a thr<'t'-5tage pnx:es,:
Stage I The ore is concentrated using the method
of fmlh llotation. TIll.' chalcopyrite
partidl"S (loat to Ihe tup of Ihe tank (ami
are lUlk'ct<'<ij while mOSt of tl)(' Olher
Figure 4 Copper extraction
Wlwantt'<l mim.'rals sink to the bottom_In
involves converting copper ore
this way. a lUll("('Otration of almost 3O'Jt,
(above) to pure copper metal
(Opper is obtainro.
(below).
St4.~ 2111<" ("oJlcl."ntrated (h3kopyrite (nmtaining rupp<.>r(II) ion~) is h"awd with
sHimll dioxide and oxygen 10 obtain ("Opper ~ulph;de (n>I'f".'r(l) ions),
2CuFeS, (S) ... 2SiO, (~) ... 40, (g) -, Cu,S (s) ... 2FeSiO j (s) 350, (g)
Sta~... 3 Additional oxygen is addNl: (,",S (s) I 0, (g) >2Cu (s}
Sll, (g)
-n,e result is n'PIl<'r metal that is arouncl99% pore .
.
Iron
• trend in
lDl'tal itself
The
~tli"g
rid
_melals{'an
IIFfl. Others
..aIrsi "
Iron Ofe (or haematite) is a rock that n>ntains ir<>n(lll) oxide tog\'tlll'r with sand
and other minerals. TI,e iron is extracted in a blast furnace_ Both roke (a ("001.
d"ri"ed ",mce of carlxJIl) and limeston.· ar<' needed in the extraction procl.'ss,
whkh is a three.stage pnX""ss.
5taxe I TIl<' ."()k(' burns in air to giw 011 heal: C (S) ... 0, (g) .... co, (g)
Staj,'" 2 TIl" carbon dioxid... rea.iS with more coke to form caroon monoxide;
C. (s) ... C()~ (g) --) 2C.0 (g)
Stage 3 The .·arbon monoxid., redun>s the iron ore to imn:
FezO J (~) ... :ICO (g) --) 2Fe (I) ... :lCO z (g)
The limcston<.' is prCS('nt a~ a purifier. It bwaks d""n to fonn calcium oxide (and
carbon dioxid,,), which reaet~ with the ",nd to form slag. TIl<' slag lloatson the liquid
iron at th.. bO!1nm of the lllast furn",:e, and can therefore be remo,'ed quite ..asily.
TI,,,. liquid iron must be refined (urth"r lx·fore pure iron is obtained.
Zinc
71n.· is extraned from zin.· or", (<'"ith"r zinc sulphide or <'.inc carbonate, although
bUlh hav<.' to I,.. convert...d 10 tim· oxide first) llluch lih' iron is e.xtract<.'<J (rom iron
or... It is burnt in a fmna.·e with coke to form .·arbon dioxid{' (Stag(' t), which;s
then r<.'du® to carbon monoxide (Stage 2). In Stag.' 3, th{' zinc oxide is r<.'du.W
to zinc and the by-product i~ carbon monoxide.
Sub_top.c Z il<><tivity ",,<1 the c!«troch,·mi,..l ",~i<..
101
B-TOPIC 3
Uses of some metals
AluminMn is a
strong metal with a
low density.
So, it is used in:
• aircraft parts
• food containers
• O\ial
1
E'E ... idtycables
(as it is much
Zinc is a eorrosionresistant metal that
can conduct
eIectriclty. So. it is
used:
• to coat iron to
pB.aititfrom
IUSMg
• tugectlei with
--~:::::;1
•
coppa
to make
the alloy, brass
• to make various
1ioc compounds
lor use in the
Copper is a very
Iron is magnetic,
good conductor of
elactricity and heat.
It is also strong and
malK!able. So, it is
used in the
"rono
"""But it
malleable.
ottsn ga/'oallized
•
{coated with zh:l or
mixed with ca'tIoI.
... --
-'"
'
bical wiring
--.,
... """"
• cooldrink cans
• coatings 00 COs
"""""" .,.,
...........
~
• cooking utensils
• hoi water pipes
• pkJg pWls.
also rusts easily.
wnidl is why It is
to make cast il'On
(an alIoy). Iron is
Alloys are a hOCl
non-m<:1als. Th.,
!"operlll'S of tt>.,
(onslitu.,nt "'~
Vly of t~ saniI
Represern
used in the .
manufaetu1'l of:
Usu.illy, onl)' a s
product' an alla,
• stool (more than
Mil of the iron
extracted is used
in this way)
(the main rn.,ul
makes stN.'l strlX
whereas lron,.-o
--..........
/of" gates ;n:t
~ _
Harmful effects of metals
As usdul as thf')' an'. m<:1ah nn also bfo toxl( to humans and the natural
Our .,xposu'", du.. to a!>sorptlon, ingestion or Inhalation _ Is
~n"lronmenl. Wh.. n
lar great('r than tit., awrage e"posun". th.. t'ff('("ts can range from skin rashes
(mercury or arsenic In small~) to organ bilu.... (mercury in hlght't dusn) 10
GIlICt'r (high dose of lead).lIig.h concentrations of sodium in th.. body has ","",n
found to inc'n"asl' blood pnossu...., w!tile prolongN uposuR' to aluminium has
beftllinked to Alzhrim~sd1sl"aSf'.
Add lIliIX' lininagE' is a C'()fl~l1tIK"!' of I1llning ml'lals. Wat~ outflow &om
mining opentlons ha'.... ;o high acidity. and this outflow ront;unlnaln water
resources both allO\.... and below the ground. In south..m Afrin. platinum and
gold mines app...ar to Ix" th~ greatest prod\lct'!'S of add mint' drainage.
~ Extraction of metals
Am_r tbe following qu<':l!lons in p;oir$:
I. I)('fjll(' the following Imns:
a) di~t1 ..,~Ion
I») 1henna.1 dKompositlon.
2. Name th., gas that is always gi''('D off when .. ml'Ial nitrate Is heated.
J. Brit'fly describe tilt' thrff $tage of iron eXlractlon. USf' ba1m('('(l equatlons to
Illustrate your desc:riptlons.
4. Do som~ rescarch at a library. Oil til" Internet or by intt'rvlewing pt'Ol,le \u
ml1ect information about the environmental impa('lS of Zambia's mining
sector. 1'rt'smt yom lindlngs to the ..lass.
102
Topi< 6 Metab
-
.-.".
p;o.;,.<1IseeeI
When a for«' is l
which eXplains ..
quantity of a <!J:fl
lattic:-., and tn., l.a
ns<', tlK>
1l('W1.,. ,
HOW("\...... nm
(as.'S, the alloy r
others, the alloy
Alloys
AlIo)'S ;t~ a homogm«Ju<l combirution of meuls, or ;J, combination of m011.als and
nQfl-rt>('tals. lbe IDI'U1s:= rJOrTTUJly miXf'd in definite plOponlons so thi-t w
P"OP"'liE's of t~ aIloy hll,,,, a $pE'CifK' (l)Illbination of the plOl'C'nit's of thE'
Wf&ituE'n1 aM1al$. Tll6I' U1mbiNtioos oftm maJ<oo thO' alloy IllO«' usefulthlln
my of the su.nin8 m.alma!l; ,,"IJ\lkl ~ on Ihrit ""'11.
Representations of alloys
US\Qlly, only a small pml'Ortion of th... <additi"" mM"l is added to a main mMal to
produ~... an aUo)' with som~ desired pr~rty. For ..xarnplC', steel;s im alloy of iron
(the main lIl<.'lal) and only a ~mall fr(lt:ti()j\ of ('arbon. "Ibc small fraction of carbon
matI's SIN'I ~t'nngrr and mon' durable. so it i5 suitable for uS(' In construction,
whell'as Iron would be too soft.
........
..... .
.......
........
- . ..
p<n """ is ....--... 10
Il.-Ictce ca>sas some _ 5 6 •
.. !he alomI, . . _
piI(>o 01 Iron
~-~J10
.~"'i:n
. .
+ ,. .'}
.. ,. t·-
I
10-""
pi<><:eCf . . . .
.,. .,
;~U~
1' ......
+1
iron
cartx:wI
no ~ OOCI.Q
atcms
3toms
(st.... is. much nOO+96
lItld ~ malIe3bIe l!>3n Iron)
Figure 5 A representation 01 the alloy, steel
ions to
,.........
mining
,,\'two a f~ is applit'd to a P\lI(' metal, the la}"ffS c,mC'asily slide aVe'r each other,
which txpLains Why metals are malk'able and dU<:tile. 110W1!V\.>r, when a small
quantity of a diffl"rffit matmalls Oldded to the ml'lal, ntw atoms tntl'< the crystal
lattk'r and tht layers can no I<ltl1lft sJkk as t':;ISily (as st'l.'n in FiguL't' 5). In such a
~,~ nt'Wl}' f~ alloy is stlOl1llt'1" t~n 1~ original 1IIt'UJ.
1I~"t'I', n<:M all aJJoys n«d to be 5l:rongt'r than I~ original mrtal. In 'iOIIlt'
~ tht' alloy nrm. 10 be lightft' or mort' fkxible thiin tht' main mtUl, and in
othe<s, the alloy nrm. to br _
ronosion-<esistant.
S..MOPi< J
A1l<Jr<
103
Advantages and uses of alloys
....
(99.8".-on a1d
0.2"- GalOO ~
•
-""'""""""""
Iv ... '"old
-=
......
"""""""
.....
-"'"
""""""'"
.
...,.,.,- -""'"
......
""'
"'"
""'"
-"'" ""'" ......,
E:'~·'::':~
--"""
.....
(75" coppel and
25% zinc)
· """
•
"""
•
•
other fmings
•
b~,
(88% copper and
12% tin)
•
•
•
•
llkJnri.nl alloyS
(9025'" altnwIium.
6'" Dnc, 2.5'"
., """
resistant
•
•
•
malleable
~-
""
appliances
•
•
•
.."
chemical ,,"'..the
prl'W'rK("
ofox)~;ux
{'1"t'f}'Whl"f(, <II
MwilOllffinm
th(' on-an a:('
Thl"pru<~
m""" oxygl'n
llakes _ and w
unlil the ohit'
huge ships
Preventi,
tlop/'lies
OX)'g<."n In
•
('l ... e'age. wi1gs.
tails etc.)
125" copper)
staink= steel
("':orro5Km. I
propellers 01
• -~
COt, . . . . .
. '3' 'I
,
"""""""
B·TOPIC
.
• hospltaI and
medieaI
"""""~
.~-
To pr('V('nl ..OI
with Iht-
tht-
lDl'U
1. Let ano1
s..n\1id.a1 pro!
....1I corrode II:
prm..mon. l:s
expnuh.... (X ,
tIM' rnA'" Ilw
leani.... lha:'!.
umk"f,lP"Ollnd I
~Alloys
NIS a'" atladl
thtr..hy l''''tl'(
Shnlla.l}". Ii
An,wer th<-
tIl\" hull< of ~h
f()lI"W~;':~:' ,:,:,,,C,C,,C,,C,,C,C,,C"C,:..,C.,:,C.,Cw="C,- - - - - - - - - - - - - -
l. Explain what is mNnt by the term "all"y".
2. Nam.. "n.. advantagt' that an all.". has ov('r a pu,*, llll'lai.
3. Many melab ar.. nI,"(' uwful when mlxN with other elements.
i1) Whill is the name /ti,... n IV thl'5t' rnixturPS?
b) Which elements i1f(' found In:
i) brow
ii) broila'
iii) stainlos .u('('\.
4. (~r 11M' following list of substilllCe: KOkI; iIluminlum; Imll; tIn;
magnesium; I"'iIklum; brus; stainkss st('('\.
From ltw list. wril(' (J<-n ltw IliIIIH'{S) of tM wbstmc:f'(sl thilt:
:0) an' resistant to C'OT"OSion
b) will COflodol' al tM hi&h6t nt('.
.usting. a< lin<
dl('ajl('ll') rno
2. Coverins
Pa.iD.ling
MallY iron
10~
=
all anc
1M palnt is ~
btlow Ill<:' pail:
to fhrct. to< :l:'
B-TOPIC 4
Corrosion
Corrosion (or rusting) is a natural pron"Js. It Is th,'
chemical w('a,ing of mdals by atmospheric oxygen in
th,' p'l's<''''''' of moisture. Although the combination
of oxygc'n and moistuT<' is commoll alnu)';t
everywh,'''' on ,'a,th, co"osiun happens fasler in
environments ",h,',e salt", pn's<"nt, tou, So, awas ncar
the ,xx'an an- partkularly Inone to "'Stillg.
The l'r(lc(!S., causes til<' metal to nak<, off. SO that
mme oxygen and moistm" can get behind thoS{'
tlakes _ and Wear down the dl"-1x'r larers of metalunWthe objl>ct rusts through completely.
Figure 6 In a few more
years, the chain on this
gate will rust tllrough
compllitely.
Prevention of corrosion
To I"l'wnt wr'osioll, it is llC«"SSJ')' 10 ,tul' the
oxygen ill til<' air and water from coming into nmtact
with the metal. There arc two way' 01 doing this:
1, Let another metal corrode instead
sacrificial prote<"tion is the Us<' of another m<'lalthat
will comxle mOll" easily than thl' metal that n,..-ds
protection. Usually, the SJnifl<"l'd metal is less
expensiw, or does not have the desiI,x1 propl'flit"S of
til<' Illetal that n .......ls prot .....tion. Mat:nl'sium is mn,,"
warti,·" than iron. So, on ~hjl's, oil rigs and
uml,-rgroumJ pilX-S that ,'onlain n",tal, magn.,.;ium
bars are attachc'<! to the iron to "attract" the ('onosion,
theleby pwt.....ting the iroo.
!;;milarly, zin,' bars a[(' al<o somctimN; attached to
th,' hulf~ 01 shil)$ to [lr<.'\'ent the m!'tal hull from
rustint:, as zinc' is more reaeti\'e than iron (and
chealX'f tn produce).
2, Covering the metal
$
steel.
tin;
Painting
".fany iron struriuteS at<: painted wit II ordinary paint
to h",'p air and water away frolll the i'on. Ilowe\,('r, if
th,' paint is scratch,...t, ..orr()';iOI1 can <:>IXU' and ,pread
1)('low th,' paint. Regular dl ..... ks ha\'{' to 1)(' carried out
10 rh""'k tor any "'ratdws in the paimwo,k
F.gurc 7 The rectangular
objects on the red hult of
this ship are bars of zinc
that will protect both the
propellers and the hull
f'om rusting.
F.gure 8 All the features
in lt1is children's
playground have been
painted. Not only does
the paint make the
playground more
attractive, but it protects
the meta! bars from the
elements.
S~b·'~p;( 4
0:>",";,,,, 105
Greanngloilillg
'I'he metals In the lJlO\-ing ~ of ma.-hin..ry
are C'O.lltM <'it ...... with oil 01' grf';ci<' to prn~nt
Ihem from coming into cont;>M with air and
Wolttf. This pro!flrti\"\' byn must bO' .....-W
._.
CflI('n.1 proprr.
" A lal'lllIlk bao
CaJvanirillgldcctroplating
This im'Oh~ th.. dipping of t .... k'ss
Summary
reactl\~
metal into mollen Zinc-. llll' thin lay..... of tif'l(' is
morl' Il'aMiw than lht mMal of Ihe nroMU«,
(u~ually, this is iron). Thl'1l'foll', the more
reaMi\... metal slowly mrrodl'S and lost'S
de<:lron, 10 the metal SIIIlCtUII', Ihl"l'by
protecting the iron flom COllosion.
Fogure 9 The!wl;l wtX1t_ on
the cables am coaling each
steel cable with grease to
ptQl~ it from
the sea air.
l'!«twos (n~
" In gtner.tl, '""'
and df'n..... TI1I
ha\".. blgh md
o Mt'lals rt'al."t W]I
uxlde 01 a hydrl
and hydrog'm A
o A mOTI' n·at ti~
its Sillt.
Corrosion and the reactivity
senes
o TIlf" rt'a. th in
hs ..... han" Sl"efl, 1M rill.. al "'hit:h lDI'tals
("0Tl"0dr d<pmd3. on lhril posillon in the
l\';>Mhily s<>lie's. 1l>f trIOR' l"f'aeti\~ rDl'U1s
rom>tk f'aSily whik thl' Ins l"f'ac1iw metal do
I'IQI COI'Ttldo.> e~ty. This a.lloo<os US 10 <:n>at .. "'ars
of protecting 1M easi.ly-<'OTfOded metals.
mort' or lessl:t'a
• Aluminium is ;II
r.. ac1h.... and It'S
• I bC'"ruo.al <k<:.
,. Somf' meuJ I:
,. SonH' meul c
~corrosion
'-'0..:..."';-''-'----
Rc:aod;vity and 1
roguu 10 The n.n obieet is
coated completely wittl line.
~ is iIIk! d>ionee !hat , .
and water wi. ever be in
(;(ltItact with the iron surface.
_
Answ.., Ihe following qUl'Stkms on your own:
\. l)efin(" thl' term "corrosion".
2. Which two subslanc..s all' n'sponsible for tht· mHo,ion of "on melal?
3. FOl the sacrificial Plotl'ctlon of iron, a "arlety of Illt'lals can be used.
a) Explain the term ·~crifltjal pro1t..."tion",
b) bplain. why copper Cilnnot be u:sed as ~mfirt.al prote<:tion for iron.
4. (;i\... a possible rl'ason why ",I exhausts t:OlTodI' mter than other steel
strucrures in tbt body uf .I. oor_
S. In an experiml'nt, tbrt't' Iron nails,,~ studil'd 0'...... a <:t'Tt.I.in pniod of time.
Thl' fint rntll was WI'iIpprd In o>ppl'T wire, lht strond naiJ "~s wr;tppl'd in
magnnium wirt. and thO' \asl; rntiI "~s 1m unt"O\"I'TC'd. Uloing }"OUr knoW~
of the rnctiYity~,dtt"'"'1ll' whKh nail WOIIld ha",t." ~ till' rt'K$,
and "'hkh WOIIId I'IQI N:\.... t."'OITOded much 0'\," thO' gi"lVII period of timl'.
,. (jenf'filllly,:llIt
(;oppt'r mt'lal is
" Iron and zinc: III
moltoxidt.".
o
Alloys
o
are a ho
metals altd nono Usually. only a ~
to IlrodlJ«' an ai
Alloy~
Common
is tl:
of coi
o To prt'\VIIt ro::c
t.....T1b......l pro
..1("( troplat.. II
o (o~t....
presmct'
Summary, revision and assessment
Summary
General properties of metals
...... 0'
iiIIg each
_'0
_air.
• A me-htnk b<md is formed by the e[{'('lrostatic forre bt'tWet'll the delocalized
"lectfOn~ (nt'gatiwj and the cations (positive).
• In ll"neral, metals are ~hiu)'. sonorous, Illillleable, du. tile, bard, stron"
and deu....,. They are also g<><ld c:ondu< ton 01 heat and <'l.·.·fridly, and
haw high ",,"U;'ng and boilin.: po;oh.
• Metals wact with oxygen to produC<." an oxid.., with ",at.., to produce ellh"" an
o"ide or a hydroxide and hydro);"n gas. and with dilute adds to produce a ",It
and hydrogen gas.
• A more "'''("Ii ....• melal will dhpl.....• a less reactive mt>tal from a wlution of
its sail.
Reacth'ity and the electrochemical ,,",rie:s
iIIIttct is
-'zinc.
• -.aI air
M.
• su1ace.
• "111e ~a.-th'ity ,,·ri.., is an ordered list of metals lhal shows whkh m ....talls
more Or less reactiv.... than th" ne"t.
o Aluminium is an ""<X"plion to th" ,eactivity ""ries rule since it Is not very
reacti"" ami r<:-~sts (·onosion.
o .-h,'r",al dl"(·... mpus;ti ...n is the b,<:-aking down of a compound du... to h ....at.
o Som<:- metal hydroxides thermally dl'<:OmllOW tll an o:<id.... and watel.
o Somt" metal ('arlxmates dcrompost> to an o:<id('" and carbon dlo:<ide gas .
o Generally, mctal nitrat...s d\"("ompose to a salt and o:<yg('"n gas.
o Copper metal is e"tracted from its or.... oy ,<.'<luction with o:<yg'.'l1 .
• Imn and zinc' metals arc extracted from thd' 01"<.':\ br rWu(!ion with carbon
monoxide.
Alloys
Allor~ are a h"mOI:C'D{'<>Il~ ....mblnation of mC'tah. or a combination of
metals and non_mNah.
• Usually, only a smaH pJOportlOll of Ih\' additiv... ml.'1al is add<.'d to a main m('"tal
to 1",>dU("f' an alloy with wme desirf'd propeJ1y, suclt as strength or f\('"xibilitr.
•
-
~.
• of lime.
~in
-.--!t'dge
_ most,
I
timt'.
C'.orrosion
• Corrosion is the chemkal w\'aring of m ...tals by atmospherk oxyg....n in th...
pr('S('IIce of moisture.
• To l'rev... m corrosion. one can allow another ml.'1al to oorrode inSI...ad
(=l'rilidal prot"eUon), ("Over lit... metal with paint, oil or greast>, or
{'I,"( troplal" (gah'anV"j Ih\' roNal.
ToJri< 6 (Chemistryl Swnm.1l}',
~isi"" and ."""'..,,,
107
•
Summary, revision and assessment continued
I
Revision exercises
l. Gin' ont" word Of Irnn for E'~h doo:'scTlpllon. ~lI\l' til<' propo'l't}' of m~~b
th~l allows tmom 10:
a) Ix- bl-at... l into Ihln shefls
(llll.
b) produ<~ .. rillKln,lt ~nd when struck.
(I)'"
2. Wh;';:h ODe of thE' following metal:; b Ihl' k"llst N'arth"f'?
a) (Opper
bl potassium
c:) gold
dl wdium
(2)(
1. Which onto olth(' f()lIowll1g metals will nOI dlsplacr hydrogm whtn il
rt"arts with waIN?
:;Ill Cu
b) Na
c) Mg
d) <:.;,
(2)(
4. Choose tll,- ron('<.'t answer. In whkh on... of tl\(' f(>Uowi1l8 reart;onl will
the metal Ion IX' displaced ffUm ih 11'111?
;oJ ZIl+ r:u.so.
c)
bl ZU+Al?l.
Zn+NiSO.
.......
.............
• [
HydIogeu
,
··",,
·o
·· ,,
·· ,
• E
[
til zn+MgSO. (21t
of
18]
Assessment exercises
I.
[
prnpetlies do
[
n...!abI<' lx-Iow showl; Infonn.alion abou1 f<lUl' ditf('f\'f\[ ruetal:5 (1\ B, C;and [)l:
of
Nltrogen
; ~~
C
low
':. -+;:m
-¥
medUn
medit.m
to
rnedUTl
j medium j good
Which m.-tal h the most suitable for mal.:lng
-
~:;
+t.Qh
i medium
('~h of
leOlStmS for rour choil'(' in ("M"h ~.
a) A metJal
·,
••
,,
• E
medun
mediun
Ill,. ih'rns? Sta!'"
• C
tWQ
(:\)1
II) A gale
(:\)1
c) The metal baS(' l'l a nK,king pl>1
(:1)1
2. )I.·lo1al, aI<' l\<KK.! ItwflnaJ and ~I("("\ri{'a1 {·olldu{1uu.
a) Nam~ the melallhal I, ml',t ,uilabJe tOi maldng el~ri("al wi,,· for
homclmld purl'0"l$.
(1 )(
b) Sugg"'l '''XI f'SSt'ntiall'.op<'rti.... of mt1a~ whleh mak{' Iht1Jl ,,,itahlt'
for making 1'1<'<·I.i....1 wi....
(2)5'
c) f.xpIain )uur illS'o\\'r in Qur5tion 6b)aoo." in
of mrtallk" hor\dillg. (2)(
d) F.xplain. u ..ng an ~u.alion, ..·hal will haPJlt'f! il Ih;, win" i~ pul ;nll':
i) dilul~ h)'drol"ltlork add
ii) a ,.h-u niuatt ~tioo.
TOlal: 20 mark.
1<-''''''
""
""
•
•
•
[
[
•
•
•
•
[
,,
,
,
,,
""""""" ,
•
".,""',"~
•
•
•
• E
<
• E
• [
•
•
•
•
[
,,
[
IDled
Non-metals
of mM..ls
Olil.
-=
o<hm it
•
(II"
''"
(2)(
-""""""
General
properties of
ns will
• Define a non-metal
• Descroe the physocaI and chemical piopeI1ie$ of non-metaIs.
• Demonstrate the labomlory preparation. collection and test fof
hydrogen gas.
.
• Describe Itle physical and chemical properties 01 hydrogen gas.
• Describe ltle Indusllial manufacture of hydrogan gas.
• Describe the uses of hydrogen gas.
• Demonst131e the Inboratory preparation, coIlllctlon and test for
bJ. + MgSO. (2)1
oxygen gas.
• Describe the phy$lcaI and chemical ptopttlleS of oxygen gas.
• Describe the industrial manufacture of oxygen gas.
• Describe the usa of oxygen in industry and In oan.ral PlOC
es
• E2lq:oU, the in'opc:otalA of !he
a'Id dangl!ts 01 its depIetiolL
lSi
orone"
or ~~,.~.~'~'~:'::,:;',:;""
,wage
B, C ..nd 1»:
• Oeo'iOi ostIale the cherT....... test for water.
manufacture
L
• C/escri)e
Describe the irIdustriaI
Importance
of water as a
• Explain the ctIlnC:I.. istics and mportance 01 nitlogeh gas.
• DeI'lOllSllate me p'epaiatio~ .............lioi' and test for 31'.'10< ... in
the Iaboratooy.
• Describe the menufaettn! or arrvnonoa.
• Describe the pI'IysieaI and chemical pl"""_""'' ...
ties ~ ....• Describe the thermal ~ of ammonia salts.
• Describe the uses of ~ .
• Describe the the<maI dissociatioo of ammonia salIS.
• Describe the uses of ammonia.
" Describe the manufaeturt! of nitlic acid.
(3)(
(3)( .
(3)(
0.
r-ba1<ling.
pur Imu;
(2)'"
(2)(
()}(
''"
Iotal: 20 marl;,,;
• Explain the impott3llC1I of nitrogenous flll'tllll8l'S.
• Describe the effect of n~rogenous fertilizers on the environment.
Carbon and
carbooates
• Describe aIlO1ropes.
• Describe the physical properties of the allotropes of carbon.
• Desa'ibe the 100000000ion and properties of carbon rnonoJdde.
• Demonstrate the Iabornlory preparaliQro, coIection and lest for
carbon ooQde.
• Describe the physlcaI and chemical properties of carboo I dicWde.
• Describe !he u:5e$ QII ca1lon dioxide.
• Ops 'ibe IhlI ~ d r.e from Iim8stone.
• Desaibe IhlI uses QII .... and slaklId lime.
• Desaibe IhlI uses d limeslone.
• ~lhlIgo .... ~lUUSeer.ect.
SUB-TOPIC ,1
Starter activity 1 (sub-topics 1 to 3)
we lim Ieun: ;III
AnS\'>"ft tll<' folk>wi"8 questiom in p;UD, and tbm discws:as a d;rss.;
I. Explain,,~ IlK' non-lm'tah art" found on thE' I'\'riodkTab!t.
2_ fist ten riemmts (their rum", and symbols) that Mt' non-lIl('U'!s.
3. Of Ihf' Iisl.l'd ~mlC'tlts in ~ 2, which 0TM'5 :arr.
a) 50Iids at room tempentur.b) liquid!; at room fl'lDpt'I3tun>
c) ~ at 100m temperature
d) found in air (atmusphe","j
e) not found In air (atmosphert')
f) diatomk molC(·ul.':I in their natural statl'?
4. Name fiw common compounds that contain non.m<.'tals.
S. Compl('\(' the table below by listing .soml' dilfefl."nees b<.'tween thl' physical
plOpertil5 of Rl{'laU and non-metals:
non-me1ak:
•
Non-rnet:ab,;a
~l"'I"ption of
I
• 1bC')' include ,
solids such iI!>
• Non-metal ior
forming (n"P
whl'rt' n is the
• TI,('$(' el,·m<':'lt
s1lells.
Physical p
Starter activity 2 (sub-topics 4 and 5)
AnSWer th... following qUl5tions in pailS. and then dlsc'uss as a class:
I. hplain, by means of a dot-and-cross diagram, how a nitrogen mol('("1,dl'
forms flOrn two nittogcn atoms.
2. Name two rummon U~ of ammonia.
3. bplain how fertilizm are uSl'ful
to fanners and gardalers.
4. N........ tmet' SOUI'C't'$ of nrbon dioxide'.
S. Explain tM Unk bl!t~ climate ellaIW'
and ca.rbon dlo~dco.
110
Topi<"7-.-ws
11Ie non-metals:
• can he $Olids, I
temperatuft· all
• are poor (lxId) ,
el«1l1eity (bee;
mo,1ng el«1ro
• are dull in appo
• ha,'f' low dmsi:
• are britlll' (non
• gfflcnlly tJa.,....,
\ow boiling poi
General properties of non-metals
Wt fint karol about 1M
non-~ah in
Gradfo 10. R«alI W following fKts ~boul
non·mf't~
• Non·mctaIs a", found on th.. far rlght.lund sid.. of tlll' PniodkTOlbk>, with the
nn"ptiOll of hydrogen, which is in Group I.
• Thf')' indud.. alllbt !lases. such as hydrogffi, t1..lium and UXfg('n, but also
wlids such as carbon and a liquld (brominl").
• NmHnf'lal ions form wht>n atoms of non.metals gain rll"<'rons, thereby
fum.ing (negatively charged) anions. Tht' anion i, g<:-n..rally n"1)tesentoo as X'.
wh..'I<'" is the numbe1' of dl."ctrons gaint(!.
o Thl'Se .. ICfIWnu h.. \'t' ~ n four and _ ...., electrons In Ihm outermost
""...
.•
Nl:II C
•
au St.
'.....====~
Figure 1 The arrangement of me~ non.metals and
metalloids in the Periodic Table
Physical properties of non-metals
..
~
~'
-,I
-t'
,
,
,
\
..
'
'
The' non-rm1;dl':
• an br:' 5OUd:s. liquids or p5C'5 al room
lt1npnatul\" and prfSSUrt'
• ~ poor (Nod) rondu(1l>n of both heal and
l'll'<"'lricity (bl'<".. u~ (bt')' do not ha\'{' ft«"moving t'lectrom in th"" structuR"$)
• are dull in aP!X'aralK("
• ha"" low densilj('S
• if.. brittl\' (nnn-metal solids loan hrnJ,; t>asily)
• gfm-rally tta\'t' "ery low melting points and
low boiling points.
SoII>lop;el
Gnlphite. which is a bm of
carbon,l;l(:ItI<b::ls pI lridly
eveo 1hCIOJgh it is a non-metal.
(_i_..,..,.... <11.-.-_
111
SUB-TOPIC 2
Chemical properties of non-metals
11'e non-metals:
New words
• are generally electronegative in natuH'
electronegative: the abjlity to
• fonn acidic and nentral oxides when It'acted
gain electrons easily
with oxygen (for example, SO, and CO, are
"xidizir>g
agents: substances
acidic oxides of non-metals, while (:0 and
that bring about "xidati"" by
N,O are neutral oxides oj nU!l-mt'tals)
gaining electrons in a chemical
• are wry powerful oxidizing al>'t."nts
reaction
• do nOl form hydlOgen :;as when they react
with a<ids
• furrll rhlorides whkh <-an be solids, liquids or gases.
Hydrogen is th" II
hydrogen romain
only. It <X<l.tfS nat
(II,) and forms l!l<
element.
On earth, hyrl:,
not part of the au
occur in watN,!l.II
Hydrogen!
Uses of non-metals
Hydrogen <-an be- I
Non-metals haw found a wider uS<' in our day_to..day lives. For example:
• Chlori",- is nSt'<.1 in the l'urifi<-atiull of water and as a hl<>aching agent.
• Bromine is used in dy'" and l"',tidd""
• Small amounts of iodin.. are ll{'{'<.led in our hodies to pwvent thl' .<weHing of the
thyroid glaml. H is also nsed as an antiseptic
• Noon is used for advertizing in Iloon signs.
• Helium is nsed for fIlling balloons tx...-aus<· it h light and not ",actin'.
• Some non-metals (such"" nitrogen) are used in fertiliurs.
• Oxygen is the key demem in cellular <",piralion in plants, animals and huma'15.
• Graphitl' (a lorm of carbon) is u.,e<f to make ['('neils.
l. Reaetiv('" mrt
Exampll':
(:a (~J ~ :
2. ReaCHv., mrt
Ex,!rnpJe: !\Ig (s) •
3. R.,a<1:ive met:
Example: 7.11 (s) .. :
The hydrog"n ga'l
ahm-" <'an he co~
dispiarernen t <)f "_
method.
The downward di!
Hydrogen gas is r
pushes the water I
10 tile top 01 the .,
Figure 2 The uses 01 some noo-metals: nitrogen for fertilizers (A), graphite lor
pencils (S) and neon IOf neon signs (C)
mlIlIIIcN_O'--"_-m-,-:ectac'cs
Answer the follOWing questiom on yuur own:
I. lleserihe whal a non-metal is.
2. Stale fiw physical properties and tl\'e cl'l'miral prop<'Ttk'S of non-metals.
3. Name two nses 01 non-metals.
4. Wilie-h of the following elements ar<' "on-m<'\als: oxygen, lithium, rhlorirw,
copper and sulphur?
_
\
T
-TOPIC 2
-
Hydrogen
H)'drogffl is Ul(" lighltst l"'Itm.... t. An alom of
h)'dmg.... ronlain, Ollt f'lf'<"I'OIl;md
~
proton
lly.ll OlUlrs rnllurall)' olS a diatomk" moJl'{'Uk'
Hyd:0\jJtii, IPS mal<es '-" _
~" 04 h
mass of 1tle un-aa.
.....
lII,' ilnd forms mure rompoun<b than any othf'f
.
. • '.<oJ,
..,. . ;--
('1(,1llt'1l1.
On ...arth, hydrol\('11 Is a,·tually quill' r,l.(" It is
not part of th... air in Ill,' alm~ph"r", bUI it d".."
(X"OtT In wat"r, naturallo:a, and p<'lroh'um,
Hydrogen gas: preparation and collection
1I)'d,ngrn """
I.
~ ~at In
Rt~i,'" _etal
me laboratory by Iht' following
......"'Ift'
~
hyd.-o,udt' .. hydl"ogc=tl g;u
f..u mpk-: Clts, .. 211,0(1) ~ Do(Otl).taql"
of''''
2. R..~i,·('
)Detat ..
rt';>Miom.:
tf~W
,,('am > metal odd., .. hydrogel} gas
.:Xaml,I(': Mg(,} .. U,olg)
---t
MgO(sj .11,0:1
3. R('active metal + dilute: add
-~
Sialt .. hydrogen gas
F.xampll·: lll(') + 211Cl(a'l) > %,,(;J,(;I<I) .1l:(xJ
Th.. hromg..n l':'I' I"('pare<! using Rt'a<1ion J
alxwl' nil be rulI«tl'd by ('ither lilt' downward
di$pb«ml.'nt of watt', or ltw upward <k'I,,~
r-ilric aco:l can be ....ed. IlIA ortt l
the I9IldtY8 rnel3I is ,. ""ll'
m
See noIe on page 97.
m~hod.
The do..nward di$plao .....Iel,t of water
~oga , gas is insoh He in water w'od
pushes the water dowr1W3rd!; as it ri$eS
to the top or the gas Jil".
The upward deIiYeri method
HPogen gas isles$ dense than ail'
and wiI tIoat to the top of the test tube,
pushing the 8If downwards.
l!I
L
dtloriM.
,_'Ii';
" ,
The test for hydrogen gas
--'"
""-
Physical
-
BMg a I:lo.a'TWlg
The .pop. SCUld is produced...men hydIDgelI
bu'ns. water is l)I'(lduced by the reac:bOn. as
the mouth 01.
jar oontaining
""""
2H.(g) .. O.lg) .2H.O(ll
Thl! water helps to eXtinguish the bUrning splint.
~ Laboratory preparation of hydrogen gas
This ",xpl.'rinwnl will be
)faterioW
d"l11on~t ralt'd
In \('TmS of ..ht'
• is 'OIllhustlb
by your h';).t"hn
vapour, aHOI
• r",mov<'$ 0.\\1
equation: ( u
i Aim
1To P"'POlU' h~"dr~n
gas and IPSI for the gas
You "illllC."C'd:
• 1" bl't'hh" wit
-~
~
• I" ...... tl.'r l»th
• I >< thl!dk' funnel
htdi""",· gas
• I >< gas jar
-~,
• I >< dl'li~'t"ry tul).,
• I >< ronk1ll ~
• SOml3MIICI
•
• zint" g,anull's
'" I >< rol>ocr st0l'l"'r
"ith two holes
granules ""' W
• blue and red litmus : F"0gur9 3 E><perirncnt set-up
paper
: 1"Tocedure
• matches
j I, So:! Ill' lhe appal'3tu~ as shown in FlguU' 3.
.~_.~.><_:,:~_~~I!~~_m.. Z. Allow a f{'W drops of 110 todrop ooto the zinc.
3. (".011«1 t1H' hydrogm gas In the &as jar.
4. Quickly rrmo'l't" the gas Pir from !hi" " .. u~r bath and pomorm the tl'Sl for
hydrugm.
S. Test tht' liquid that forms in the gas lar With litmus papt'f.
-
. ,'"
-
,..
..
----
i
.1
O~lItions
1. What rolour is tht" hydrogen gas In Ihe gas jar?
2. What did you obS<'rw when til'" burning splint
3. Ilid
th~
wa~ plact'd ill th'" gas jar?
liquid havl' any effect on the rt'd Or blut, litmus papers?
CoachlSion
I. Which propeny of hydrogen auows us to use this mrthod of collection?
2. Write down a baIanCt'd l.'hl.'micaJ. ~uation for the tr'aetion that tal>ts piau'
in the «>nlc:al flask..
114
'tope 1
_
In rerms of p~
'" n.*lurk"'u. U
'" in5Olubk' In
'" nt'itber ac1d
'" Ihe light("',! (
Industrial
H)"drognl gas"
1_ Crack... g
When certain n
into SIlliIller me
(CIl.) Is <'tlld:1'd
\"",ry up(>llsi\'(',
We will le..m
2. Elcctroly*
A concemr.tt<'d
prodlK"l" h)"drOl!l
t'lK1:roI~s. llv
otll<"J IndUStrWI
chlorine gas a:x
hrdro,ydf'.
An<."ll"ClricCll
p.lsSl"d Ihtou;;h
ell"Clrooes lhat I
ront.... t wilh tm
separmNJ hy me
memhran('. ·nJC
reactions that IX
electmd... u<' r"i
the prod",,·U.
-""';'''';;jo~", as
Physical and chemical properties of hydrogen
[n
t<"Jm~
of ph}'l'inI1 propt'rtirs, h)'drogl"n gas is:
• roIoo'l......s, taSll'less and odourless
• in~ubk> in ""I('r
• "';Iho:-.;l(id
no. alblil1C." whto lo::stf'd ,,'ith litmus pilpl'f
• th., Iighlest of alllh<'@S('S\it is 20 tlml"i lighll'f than air).
'll"S
In l..rrm of ~all>rope1't~h}'drogm ~
... 1< combustible in o.~~ and. bums with a sm~ bhw llallK' tu form w;al...
<,,"pour, xrordiDg to tms t"qUalion: Il,(g! + O,(g) ---> U,o(g)
• rmJO<"'l'S OX)'g\"Illrom roppI'f(lIl o"itk 10 fann 50Iid Coppel, alT(ll'dlng 10 Ihis
equation: CuO(sl" 1I,1I! ~ Cu\<I. Il,o(g)
Indusbial manufacture of hydrogen
Ilydrogen gas is lllallUfiK"lurt'd using ont' of Ihl" induslrUI
---
When «'rtain muk..."'IlII"S thaI (ol1\aln ,...bun and hp1rt>K1'" all" nil<"\.;t'd (l)fol:l"n)
into small....- m"l''':\'ll-s, hydmgl"l1 gn is l'",dIKt'd. Fur <'urnl'l.., whl"ll tnl"lhan..
(CH.l is crack<."d, arbon and hy<Jrugl"ll !las are produn...l. HOlWI.'I'I, Ihis pr(~< Is
vl'r)' .."pensin', So it is 11U1 "u'I('nlly uSNI on a lars", seal",.
We willl"'am ",or'" alxml rrad,ln,!; in Topic R
New word
A (un(mtralt"d ....lt watl'! sulutiun, I>f hrlm·. <.,m
l>Iodu<... hydfUj;rn ~s If it und",rgo('S
electrolpi.!;. This prO<"rSS alJO product'S two
oIh<.. industrially useful chemlnl!>:
chlorine ga.~ and JOdium
h}"droxidr.
An elmrie ('\frf{"lll is
J"'S'I'd through two
rlrctr<:!otlM; 1lu.1 aIr In
("()lltacl with lhe- brinr but
srparatrd 1.»' mr::ms of a
mrmbranl:. Th<: d><:mlcal
reactions that <X.'CW at each
rkoctrodl> al'1,' responsible for
Ihto pmdU(!S-
------"=..:::=----electrolysis: the decomposition
of a solution by means d an
,,-•
--
follow.
l. Craciilllg
2. Electrolysis of brine (salt water)
*'ttion?
mcthlld~ lhal
"[
-~
"'-
- =-'l_e-~!'1" _- _' '~=; ' ~;~i:;.~r -~
FIgUre 4 The dccbolysis 01 brine produees
hydrogen gas and other products.
SUB-TOPIC 3
3. SteaID rrlOnDing
St.
A nalural gas (usually mo:tha~1 Ull<k.-rgoes steam rriQfYtling ill a
1"<Jn"SS.
1: M~hatl(' and ste-am an" ~ 0'\," a hot nki71 n.lol1y'St at 900"(;. Tlw
...anioll p,rodocti <'afbon mooo:tidf' and h)'drogpn ys.
01,00 .. 11,000 ,.-+ C.Ooo" 311,00
Sla&", 2: n... prodlX'U from Stilgt' I an" mixnlwlth m'm:" ~1';1.m and paSS<'d 0\'t'I' a
hoi iron catal)"S1 at SOl) -c_ n... <'afbon mono.o:ldl' ~ ron,~nlIO a.rbon
dim:idl', ...hk-h Is n.s.lly Sl'J"U'3tnl flom til<' h}'drogen gas.
<Xllg)" IIp(g)
CO,(g) t II, (g)
two-slOlgl"
--
=..s..
C
0Xygm is found ...
lbtal~m
OX)l:tfI po II ol1'So
md mmy nrin=lIr
Oxygen ga
and coiled
The mixtul'l' of <:artxm dloxidl' and hymog,'n l~ passed through very <:old watl'r 011
high pH."SSIII'l' to diS5<J!\,(' thl' <:arbon dioxide. Thl" h)'dmgl'n l-:as bubbll"S out of tht"
water and Is dri,'(/ as It I'J\WS through silka !,:1"1.
In Ihl'laboratory,
• th.. thNmal cat
IXlIa5sium ch!(l
• th<' d~"mposit
Uses of hydrogen gas
The test for 0)
Indostrially, hydrogl"ll KilS is USl.'d:
• In the manufanurl' of ammonia (Ihe lIol1>E'r
procns): N,OO .. Il,oo .....~ Z-'\'II,oo
• as;on "wironmentall}'·frit"ndly fuel (whl'll
It hums in oxygen, il forms Wolin, not
,....,-,.
' - EI
....,
• In the manufactutf' of hrdrochk>ri<" xid:
h)"lirogen ",an, wllh ('hlori....
(11,00" (]~(g) -+ 21l0(glland II... wsulling
h)"dIogm chkJrid<:o gas is dlssol\"l'd in waU,T 10
fonn a solution of hydrochloric" a<id
• in Ihe hardening of oils In th.. manufaC1UI'l'
of margarine.
~ Hydrogen gas
Activity 4
F'ogure 5 Hydrogen fuel eel cars
a<e a1<eady a reality. In the Mure,
...
_.
hydIoge.. retuelling stations w1ft
become more common all Ollef
,\nSWl'r Ih.. tollmving <11lt'Stlon< 00 your own:
I. Name thr.... ",OUr('E'S of hydrog<,n,
2. SIal.. four physical pmp,mln of h}'drogl'n.
3. Stall' two chl'minl propl"nln of hydrogen.
4. Magnl'$ium r....C1S wllh w:atCT, stl"ilm and adds 10 produa b}'drog<'n.
Compll.'tl' the following l"qUillions:
a) ~lg('S) • 11,0(1) - •.• , ••..
b) Mgls) 'Ila(~) '
.
c) Mgl'S) .. 1I.O(g) •••• " ._.
116
Topi<"1
N<&_
Carry oul lhis exp
1-
Experime,
Mat... ri.ah
You will n<'<'d:
• 2 M tl'Sllubl':;
• I ~ test tu~ s:t
• I ~ wooden sp
• mal(,~
2Omlof~
hydrogm. pl'«
•
solution
• Smlof2M
-""
· - """""
(KI) solution
Oxygen
B-TOPIC 3
OX}ogm is found
itS
a. dbtomil: molcruJe in lliltun:'_
n.... a.\IDCISphfn' ronta.lns iIIJlIlI'OXltNtely 21% 0(
oxygm gas. It Wo <In."UIS In watl!l, sa.nd,. silica.trs
a.nd ma.ny rnirH'nh in 1M form 0I;aJ1 w<.ide_
Oxygen gas: preparation
and collection
In tbt bbor:uory. ox~ is ~ by:
• tht thrnna.l nta.lytK d«omposition of
pouassium chlon.lt: KOO, (s)
=.'
Rguq 6 Oxygen P is wKSety
used n hospitals. although not
oft... in its p;.,.. form.
KClO(s)-I- O,(g)
• the dl'cornJ'O'itlon of hydrogen pt'<oxldr (5t'r Acth;ty
;I
below).
TIle test for oxygen gas
Place a. glowing
splint in a jar
cootaining lhf!
The spIim.
relighlSto
,~
IIame.
prod~.
The correcl combination of fuel, heat and oxygen
is necessary lof combustion 10 occur. The
glowing spIim. has enough fuel (the splint rtself)
and heat bul not et'lO<..gt oxygen is present in
the air for rt to rtHgniIe. Once in the presence of
pure oxygen, the splint easily re-lgnites.
~ Laboratory preparation of oxygen gas
.... cell
ears
.. the MUt9,
wl:iIDc:>o os wi.
Carry outthi5 rxp<"rimem (on this pag" and tho:
1-
Experiment
MatetUJs
You wiIlllft'd:
• 2" test rubf5
• 1" test lube sund
-
• 1" 1\"'lXXlen splinl
• matches
• 20 ml of 3O'lIo
hydrogen peroxide
solution
• Smlof2M
potilSSiUm ~
(l<J) solution
• safety goggles,. g\o'Je
n~xl)
in pairs.
.-------:Ailll
•
To prepti!' oxygen ps by mullS of tM deoomposit>on
of hydrogen pl'IO:Ode
P'oced......
t. Pbcr thr test tube ronuinllll the h)'dtogm.
~ solution in tbt ll'St tube Stand.
2_ U,lIntT 1 lights 1M splint $0 thlt il glows,. but
doe not bum with a. ft;Ime. Lea.1ll('[ 2 ~ ludy
to pour the Kl solution intO the toest lUbe.
3. l.e;mwr 2 quidJy pours the KJ solutkln 1n10 the
toest tube and sunds bad<.
4. Ltanwr 1 bring5 1M gl0win8 splinlto the' mouth
of tbt tl'S1 tube. See Figure 7 on tM next page.
Sub_'opld o..nen
117
OIn;rn..tiOIU
--
Whal happml"d 10 1M woOOnl splinl whrn
il was broughl rxw lhC' fillt 1f'St tuM?
Conclruio..
I. ExpWntbt'rok"ofthfog)owing
wooden splinl.
2. Explain lhC' rIM d tho:' pllUWum ioltidl:~tion; "1tlO il <II rt-xunt Of <II eataIy5t?
3. Wril~ down <II balann'd chemial
njUoalioll for tiM' It'<IlC1ion that <X'CUJTl,'<,l
Step 3: Thr air b'
rooll.'d :0
ex~ fCE
lr.>ctions.
Il'fl1O\'ft! I
ocher <II: tt
Sto.'(J 4: The liqtd
Ir.>ctionati
nitl'l:>gffll
bl.'fOl.. IM
FIgUl'll7 Experiment set-up
5O:panllt'd I
boiting po
are:
,. Nitrog...
,. Argon,_
Physical and chemical
properties of oxygen
,. ()xrgm ,
Stl'I,5: Thl' fraetia
In terms of physical pro(M'r1ies, oxyl:ftl
• colourleM and odourl,,"
• les~ <k-me tl\a;n <IIir
• slW>ttr soIubk' in .....tl'.
ga~
• nrit...... acidic nor <IIlblilll1'
• 1.~'l'n1i<1lJ
to <"t>l1lbustJ,on.
In trnns of chemini
I'l'acts
()')jnlk'n'
b:
pr~ifos, oxyg..., g:.t$
Uses of oX!
F\gI..ft 8 Oxygen is' eeded tor
this match to bum, but oxygen
itself does oat bum.
"ilh:
• non.mM"ls in combustion reartions 10 form <IlCklIc oxidl"S. For nantple:
,. 2C(s) + O,W .2COW Note: l1>e oxygen ~as b Iimitl.'d.
,. C(s) + O.W • co, (gl
NOll" Th.. oxygen!:ilS is In exCl.'Ss.
,. SIs) + 0, (g) ..... SO. (g)
Note' Th.. oxygt"n !:as i~ limit""'.
• m{'lal. to foml ba,k oxide'S. For example:
Dill YOll knovl?
,. 4Na(s) + O,{g) 12Na,D(sj
SOd'um oxide (Na,O) is WI
,. ZCa(s)+ (J,(gl ..... ZCaU(sj
importanl ingrediOOt of glass.
,. JFl'(s) ~20,\g) I ~'e,U.(s)
Industrial manufacture of oxygen
OX)'gen b obtainf<! from the <IIir by th.. prOU'Ss <:aUf<! lhe fra<:tiorull dbtillatkm of
h'luid air.
Stf'p 1:
<lliI is fiJteted to reil"lO'.~ my dICit p<Ilnidn.
St~ 2: It b coolt'd to g<'t rid of water
and then J""l'l'n5l.'d to
It.''ITK).'., <1111 the nrbon dioxide u>d pollutants.
n....
118
Topic 7 S<lft.m<ub
'''pour.
IndUSINllr, OX}'ge
• in the produc:Jc
blown throu:gh I
• II> tnl'1.<Il1 rutti."'&
mixf'l.! with OlCer
~y""'~.AI
hi!
bum~ ~tlOnglr
n
able 10 rul th,...,
thMn. MNal ",-ri
tlw <;,)rnr war.
• as all aid to help
natulal supply Ol
(for uarnple, ho
• as <II fud.
1'atunlll~', oxygen ~
• tht.' rl'Splnltion a
~nrbon,
• rusting: a Il'actio
a brO""II subs:aI1l
wI10k' numbf'L
ep 3: 11l<' air is rompressed and then
rookd to -200"C, wher(" it is liquid
"Cl:"pI for the noon and helium
fra<:tions. 'fht'St" 11\"0 fra<:tions are
relDO'l'ed and separaled from eKh
other al this poinl.
tp 4: 11K' lique6ed air is sml 10 lhe
fra<:tionating column w~ the
nitrogen gas is boikd off first,
bef~ the oxygen and argon afe
~ral«l from each other. The
boiling points of Ih<'Sl' hacllons
-196"C
-190"'C
.~
.. Niuogm:-I96"C
.. Argon:-I86"C
.. Oxygn>: -183"C
Step 5: The fractions;lfe storro In gas
<:)'limkrs for futuf(' U'K".
Uses of oxygen gas
- 1&1 "'C
--
Fogure 9 The fractional distillation 01
liquid air
InduSTrially, oxygen is used:
" In lhe prodU<1iOll of sleel (oxygen is
blown through molten Sleel to purify ill
" In metal cutting and welding, Ihe gas is
mixffi with act'tylene 10 form oxyact'lylene. AI high pressure, Ihe mixture
lJum~ slrongly 10 product' a flame that is
ablt 10 cut Ihrough metals by m<'lling
them. Metal ..-elding (joini~) is dOl1e in
the sa.m<' way.
FIgUre 10 Oxygen is nee:led for
" on an aid 10 help people bftatht when'
metal cutting and weldirlg.
nalunol supply of OX)'gffl is insuffuiml
(to. exa.mple, hospital patients, mountain {limbers and dt'ep-Sl'a di'~J
• as a fueoI.
Natually, oxygen pIays an important rolf'in:
• the ~tion of organisms; this in\'oh't"S the burning of g10C05f' (fuf"I) 10
PIOOua arbon dioxide, watn and ~gy,
• I'IlSting: a reaction taU$ place bet"'ffIllron, water and !he' oxygen in air to lorm
a brown su"'lan~ 1\'llh the <:hemi<:al formula, Ft".O ...dIP, wlH-re x <:an be any
wbole num~.
Sut>.topioc j
O:<non
119
Ozone
Thete
All own~ mol('('Ul~ ronsisu 01
thr/!t' oxyg~n atoms (0,). Abo~
th~ tTOPOSI)h~r~ and bt-Iow the
SITiltospltcrt' Is a la~r of ozone
that prol«U th~ earth from the
sun's harmful Ullra\iolet (UV)
radiation. Wllhout iI, too much
UV radiation would J'f'»rh ttwo
earth, and destroy most lorms of
-Add a feY.
drops of ~
"""""',
SUlphate.
•
,,~
llf~.
Man-nude chemicals in th~
almosphen' an dt'plt1~ th1s
b)Tf of ozon~. In tM 198Os, It
~sloundthalsubs~
--
"'~
"'~
ronlalnlng c:hJorofluo,oca~
(CFCsJ. soch as rclrigft-ants and
IIf'fOS01 nos. Wl'n' slowly
dPstl'Ofing th~ 0Z0l'H' b)'ft.
1lK' CFCs aJ'f' rhmlk"ally
FI{ItO 11 The dil'letent 1aye's 01 tho ~'lr
unrnnto.... in Ihrir rontalnen,
all IIo$pli'N e
bul art" abk 10 leX! with UV
liptl, whkh spIlts thmt 10 gi\,.lfft dtlorill\" ~ ~ radk:als brf'ak tilt'
~ 00¥.1l 10 OX)'gt"1I
Importa
• dll okiI".
"--.
• wal«sp
g.u..
'The d.a.ngt'fS ot 0Z1ClrW la)'ft ~ indudr skin~. (due 10 100 moch 1.1\'
oo~lion) and 't'Sptratorydiwase sud! as asthma and ..... phywrna.
Water
Water is an oJddlo of hydrogen. "Jb.erdOtt. its ~ chemical nam~ is hydrogen
OXide.
Physical properties of water
"'ft Ih~ f
1_ In whid
2. Une l.:lbl
h)"drogt'l
....""tl"f:
• Is a colourless, odOllrl~ liquid ,,'irh a flat
tasl~
• is II"-llta] 10 litmus
• h.asa dl'fUily of I gfcm' al"·C
• boils al lOO"i:; and 1I~zr:s al O"C..
F9'1l! 12 A waterl'TlOlecule has
an angular shape.
120
Topk 7 Non·",.,aJ.
a) Wlit~
b) Narm
c) 110'0"
d) What
Naml" tho
of WaIN b.
a) Wltat
b) f.xpll.l
c) NamE'
The tests for water
Add a few
drops of liquid
anhydrous
copper/II)
sulphate.
The white
copper/II)
sulphate turns
hlue if water is
present in the
sample.
Anhydrous copper{lI) SUlphate is able to
incorporate some water molecules into its
crystal structun> to form hydrated copper(lI}
sulphate:
CuSO. (s) + 5H,Q(l} "" CuSO•. 5H,Q(aq)
Hydrated coppet(lij sulphate is blue in colour.
Let a few
drops of the
sample land
on some
The blue
Cohatt(lI) chloride is also able to incorporate
some water molecules into its Cl)'StaI
structure:
CoCl,(s) + 6H,O(l} "" CoCl,.6H,O(aq)
Hydrated cob3Jt(lij chloroe is pink in colour
cohatt{lI)
chlorK::le.
cohatt~l)
chlorK::le turns
p;nk if water is
preseot in the
I
samp~_
Importance of water
• drinking and cooking
• washing and bathing
• water sports
y
much UV
.-:vIe has
FI!JUf1'! 13 Water
plays an important
part in Zambia's
•
•
•
•
•
•
•
ilTigation
livestock farming
extraction of minerals
hydroelectric power
transportation
processing of food and drink
mamJlaclure 01 chemicals
economy, as a
tourist attmetion.
~ Oxygen and water
All$W.... Ihe following \1"<'5li"n$ 00 you' own:
1. In which gm"p and p"rio<.! of Ill<.' l'{'riodic Table i$ oxygen found?
2. On<' lahmatory 1"{'l'araliOll of oxygen in\'olvM the decomposition of
hydrogen p<:roxid{' u$lng a calaly$t.
a) Write down a halanc<!\l ch{'minl ('\juation for tht: reaction thaI takE'$ plac{'.
b) Name a \'alaIY$1 that can Q{' usoo in thiS f{'<lchon.
c) How would you prow' that Ihe gas PWllafOO i$ oxyg{'n?
d) What do you unMrstand by the term "calalY$t·?
3. Nanl<.' the m{'lhod thaI is u${'lj to obtain oxygen from aif.
4. Wale, is an OXide of hydrogen.
a} What are the boiling point and ff<"Czing point of waler?
h} Explai" how you wOllld test for the p,osen....' of watN io a substa''''e .
c) Nam{' two industrial uses of water.
Sub.top;.: l Oxygen
121
SUB-TOPIC 4
Nitrogen
• !l«aU>t' il 11l:l
into t~ l"r::pIl
• It is abo pu."lII
!,<,trogerl ocwpks around ~ of Ihr loti.l
air MOWKl us.
\'01W1lC'
of thr
In lIs f~ Sli.t~, il ~xhts lIS a dialomk moIKUl~ (N,) in
....· hich thl" aloms i.l'l' joinrd logMhrr 1»' a tripl~ ('O\'alml
bond. Thl"St' bonds i.l'l' IlKTedibly $trong. SO nitlog{'n gi.S
d"o's nm rl"adlly l'l'i.("\ und{'r ordinary ("(",dihans.
~the
. 0°:.
Figure 14 Nitrogen's
triple covalenl bond
rh~ofthe
Ammonia
Nitrogcn lias Is obtainrd from Ilw air by fractional dislillalion of liquid air. Se-e
pages 118 and I I <l for the deulb 01 this prO<'O'SS.
TIt\' ammonia 1ZI
bonded to thrrt'
bond~_ Ammoru;
atmosl'herc, bftl
through the d«:I
Physical and chemical properties of nitrogen gas
Laboratory
Industrial manufacture of nitrogen
In terms of ph)"SicaI
propt'1'l~ nitrogen
gas b:
Ammonia
Is~
'~and~
an ammonium to
• lrss dense than air.
Z....' lI.Cllaq}. CI
211,0(1) + 2..'11,1
lonk:tll)', the tea.
21'1I;(aq) t OH
In I..nns of ctll"tTlical propl"l'tll"s, hydrog=
gas is:
• gen~rally Ine", although It <Jon r1."art \\ith
wm.... substanCf'S undcr very Sj)('\itilconditi'JIls
• "nly slightl)' soluble In water.
TIt" salt and all...!
th" ammonia gas
passing It througl
ammolila ga1 is.
coll('("\ed 1»' the d
it is rollected ~. 1
Uses of nitrogen gas
• Whm lique6l"d, nilJogm gas is USft.I to
quick-freeD' foods and liquids. For
rx;Implr.
.. ~ foolh u .... hozrn ~ lJ,quid
nit~ at lhc fanoril"s whtf.. tlwy an
prodlK'tl'i, so thai they can be
trilnspo"1'd to shops
.. ,II hospitals, liquid nilTO&en Is uK'd 10
kl'Cp tls~ur sampl"" Im:ren
,. In industrial plant" HIIUid nitrnscn is
use<110 Il"{"('ze liquids in pipPl thaI need
revalrin~ - thaI war, th.... pipr I.s repairrd
without any liquid bo.'ing lost In
theprocm.
• 1>.nrt>gom ~ that is prt.1!aJ'\'d ~Irially is
USIrd to makeammcnia. IM"e JMb'" 124}.
122
T""7~_
air dut" 10 liS Io1O',
Did JOU kntrtV?
The test for at
FIgure 15 The boiling point of
nitrogen is -195.8 'C, $0 below
this lemperature, nibogen exists
as a liquid. Uquid ,libogeh is used
lor rapid Tree2ir19 and coolWlg
_..-......
Bring a damp
rf!d litmus paper
dose lO the
mouth of a jar
contair*'g II'le
,.,.
•
•
- --./
.~
f&>0\1*'"
? II bond
Ilecau~
II Is unreactive, nitrogen gas ran br usm to Pn'\1!11\ fires. It b pumpl'd
into t~ Il'Illpty s~ in oiltank{'fS to avoid any a<ridenlallgnition of vapows.
• It i5 aIso pum~ into food p;acbglng 10 keep the food ft~ for long"_ By
~ tIlE' air (oxygen) in thr ~bgirlf: with nitrosm gas. thEft is 1f5S
chan<'r of
food ~ dlK" 10 Upc:lS\I<" to air.
trw
Ammonia
The ammonia molK'Ule contaiIu or'IfI nitrogen Uom
bonded 10 thl'E'(' hydrogrn atoms b)' single 00\...1=1
bonds. Amllloni<l gas is found in lT~ qu.anlili"'i in thl'
almO!'phere, bt<:1l~ It b rele.. ~ into 1m- almosphl'w
through thl.' lIec'ay uf animal and plant matt....
laboratory preparation of ammonia
Ammonia is made In the laboratory by luning
an ammonium salt with an al\;ali. Fur <:'.'taml'le:
2NH,<.1(all) + Ca(Ofl):\aq)-J. caCI,{aq) +
2Hp(l) .. 2NIl, (g)
lonially, lht' rt'aCtk>n is:
2.''11; (aq) + 011 (aqj -+ 2:"11, (g) .. lip (I)
The yJl md alklllJ milI:tun' is ~a~, and Ihm
tllf' munon1.I gas IS rolI«ted and drkd by
~ It throogh calcium oxidr prlk'ts. Sino'
aDlII><>IlU. P is solublr in ...aln, II cannot be
roll«1~ by thl' displ~l"nl of waIn. InSle~,
it is colleni'd by thl' downward dhp1.a<'t'menl of
air dul' 10 lIS low densit)·.
FlQUre 16 1he ammonia
mo!e<:\lle has thme
$ingle covalent bonds.
•
-• ---)'==::;;;;
~-
(J-NH.Cl_~_
•
~~
Did you knOll/'
Figure 17 A simplified diagram
The ammonia molecule has a
pyrimidal shape.
showing how ammonia is
prepared and colillCled in a
laborala<y.
The test for ammonia gas
. ' - .\.., "Bring
a damp
_W""a
red Irtmus paper
mouth 01 1M
contani'lg the
9=
- _.....
""
......""""
tun!;
I Whan ..,.,.... Iia dissot_
- in the walti' on the
Iitml.Js paper, illorms .., ........... hydroxide.
wtlich is a base. The base tun!; red litmus
bbI if the
gas is "',.,.... oa.
I
Industrial preparation of ammonia
TIlE' Ilaber prUO"S5 Is thf" mMhod lhal b usN to
prodoct' ammoll!;a <Xl an lndU-;UiaI~.
Ammonia is;!.D important rommenUl m~-mkOl1.
as it Is usN to mala' fl'nilizeon for igl'iru1tull',
The Haber process
Physical.
FritzHaber~woe<l
31,."01"
a ~ to
produce
on a ~
..... ~ 1908. This "l8lhod
made it P
) .... 10 proWoa
~ ao>d eq:+ I " "
cu,.,...
ciaII).
In this pr~ nltrogm gas (from 1M frJoCtioflal
distillation of air) and hydrogt'n gas (from
rn<"thanl'stl'am 'Morming) alt." l..,mbinl"d to
form ammonia i" a r('\'frsiblf It."action.
Sll"p I TI,.. mlXlull.' of gases is purilil'\l and
theIl compr('SsN ulItH Ihe l'rl"'surl" hi
rl'adws about 250 almosphl-rf.
SI'1' 2 Th.. mmp.('SS('d gas mixtu... is l'uml'('C.I
Into the COlWfrler .. hamb<'r, whcr<, it
limn o\'er be<.ls of fine iron 1"'1Ieu,
which;><1 as the catalyst in th.. r<'U'Iion. The temperatu~ lnlhis chamoc'
Is kl'pt at a high t..mpentUJ'1." (around!>OO .t.:).
Step 3 TIlE' rt';oction that OITUI'< is KAO + 311:(g)" 2KII,(g), bul only abcoul 12'llo
of lh<> mi,llurt.' is connrtl"d to ammonia gas.. So, th.. remair1irIs (Unn'acll"d)
gas m;";tur.. 1s smr through the CQrlwrt{'f again and again. until aU of the
milctu'l' has bto!'!. n)l'\\Tf1cd.
,
,
Old you know?
BeIore Haber ~ tI'os
"oeU>od or producng ,obClgei ,Iar
use in IetiIizers ao>d ~
Itle IOat:l was depa dro II on
~ (bi1:I diopplngs! as a
scuce 01 fertilizers lei use ...
agricuR..... Most of tha world's
guaN:I for fcr1ili.!ers came Imm
Chile. But once th& Habel
J
......
Nt
-
opllat
+
Fogurn 18 A:schematIc diagrarn of the
process was lnplemented on an
i1duslriaI scale, I!lere was no
longer a need 10 mine ao>d ~
guano, ao>d ChiI&'s ecollOl'"!
suffered eJlOll'lO<I!tt' Haber is
stiI cm:Iilf!d as "" ~ voho
i'weo>:ed Itle most ~
"'d.Istnal pi'
$ Clf _ 20th
"",,",.
In tl'rDU of ph
• hua pungt'
• Is a colourlf
• ~notbc
• Is len dl'lUl'
turns damp
• Is soIubll' in
In terms of cb
• '('acts with
» NH,(g) +
• waets as a Il
In the <'<jual
of ammorUo
• bums max'
wat.. r.
» 4NH,(g)·
In terms of cb
• rt'aclS with •
• for 1'Jta:::lj
• Is uSo<'<! 10 pi
• for examl
Activity 6
Answer the fol
I. Stale two,
2. Ammo!ti3
a) Wrill' a
hy"""
b) Naml' I
c) Stall''''
pnx=
3. Deaibt' t.
<t. Writl' a ~
...~.
S. Ust too: p
124
Topio< 7 _~
Physical and chemical properties of ammonia gas
tn terms of physical properties, ammonia g"":
• has a rlmgen! smell
• is a colourle-;s and poisonous gas
o does not burn in air
• is less dense than air and Can easily I", liqu... fi<."d
• turns damp n>d litmus papl"I blue
DId you know?
Ammooia is the only known
alkaline gas.
• is soluble in water and forms ammonia 1001ution.
In terInS of chemical prop"rti...., ammonia gas:
• reacts with hydrogen (Chloride gas to form denS(', while furn('s
» NII,(g)+!I(](g)T"NHFI(s)
• real1S as a reducing 116",nt (so it is oxidiz<:d in a reduction-oxidation reaClion).
In the e<juatlon below, copper oxid... is '<."ducffi to pure ropp"" in the pn'5t'm:e
of ammonia, a reducing agent.
New word
,,,.
3
~
I,) • 2NH, 19)
---+
3'
II
(s) • 3H,,0 (I) + N, (g)
_oil
• burns in oxygen to form nitrogen gas and
water.
ollh~
» 4Ntl, (g) + 0, (g) ---> 2N, (g) + 6Hp (1)
--
.,.,,,,,
reducing agent a substance
which brings about red...etion
by donating electrons in a
chemical reaction, and '" the
~seif oxidized
process is
fn terms of chemical properti~s, aqueQus ammonia (NlI.OJI):
• reacts with an add to form a salt and watt'r only
" for exampl,,: NII,o1l (aq) + IICl (aq) ---> NII,CI (aq) + 11,0 (I)
• is usro to prepare metal hydroxides when reacted with metallic salts.
" for example: Cu(NO),(aq) + 2NHpil (aq) ---> Cu(OH)o(s) + 2NIf.NO, (aq)
~
•
•
"'.
~ Nitrogen and ammonia
Answer the following questions in pairs:
1. State two u:;e:; 01 nitrogen gas.
2. Ammonia can be prepared hy the reaction octw.,.;:n nitrogen and hydrogen gas.
a) Write a balanced cbemical equation for the wa<;tion'h<:tw"",n nitrogen and
hydrogen.
b) Name th" process used to manufacture ammonia.
c) State where the nitrogen gas and hydrogen gas com" from for the Haber
process.
3. Des<.Tibe how you would test a gas sample to set' if it is ammonia.
4. Write a balanced equation to show how ammonia gas and hydrochloric acid
gas react.
S. List fom ph~cal properties of ammonia gas.
SUIHopi.< 4 t<inogen
125
Thennal decomposition of ammonium salts
Importa
Ammonium ...:lIs f'ithft
dt'romposco or Sllbli.- (dunges
NH.O.'-'_
din'nly from ~ Did 10 ~ psi
when Iht')' ill" healed.
I. ""lim h..~tf'd, ammonium
chlortd.. mblimes to
ammonl.l. gas and bydtog~n
chlorld~ gas. Wb"n 000100,
till' opposite reaction oc<:urs:
Figure 19 NH.Cl sublimes when heated and
NII,Cl (sl "" NIl, (g)'" IICl (s;) creates depow higher up on the cooler pari
Z. Wb"n huti'd, ammonium
of the tunnel.
nllral.. deromposo'S 10 prod~
dlnllrogt'll oxide gas (N,ol and wattt
~ll.r.:O.(s) -> N~O{gl'" 211,0(1)
3. \"lwn twatt'd, ammonium nrbonale d«om~ 10 fonn nrboCl dioxide,
¥fatl'l' and mnnonl.l. ~ (NlIJ,c..o,{lIQ) • (;0:00 ... 11,0(1)'" ZNII,OO
All fco:nilizt't
---
Uses of ammonia
Ammonia is ustd:
• In the manufacture or nitric actd (...... ht'low)
• In the manufactu of feniHz..rs such as ammooium nitrate (Nll,KO,1 and
amm()Oium sulpha ((NIlJ:SO,1
• as a ....fris;eratll !><'cauSl.' il lltlUifi", easily and Is a liquid at -33.34 'C
• as a househuld cl..aner for so!t("ning wat...r and r..moving grease Slains from
dothes
• to malo;e manufacture explosi~ and gunpow<.\t'r.
alllIDOrtU, ,
oonsists~\
So, apan fTc
ph~"""""
• potassfun
• amm"nl~
• ammoni~
• ammnnlu
• Ufl':a (CO(
n._.
~
lelilaos {nI
-.n.o
..ill"""", ill '"
.""""'
...,-deIodopi, ...
BecauSr' all tt
ollE'Ctl\'elyl
'!'he yield a
the (")imatk Cl
the lota.Iland.
• suppI)'lng t
EartrimtsaIl':1
Manufacture of nitric acid
Nitric and ",XIS wilh ~m.rnonia 10 fonn an
Did you know'?
Imporum fftlilfaot", ~mmollium nltr:al... for Ihls
Nitric add is abo known as a
f"~, nitric" add is industrially prepared by the
spm 01 nib'e cw=- .... ~ is a
Ostwald prO<'t'SS. which ocrurs In Ihret' stases.
hV"iY ..... ,O$i ... and tDJ<ic acitt
Stag(' I Ammonia reacts wllh o:<ygen In the
p...'smC(' of Illatinum-rhodium alloy
catal~1 at 9OO·C to Imm nitrogen 1Il0110:<i(\",:
4NII,lg) ... SO:(gl '4NO(g) ... 611:0($1).
Stagl': 2 TIl(' nilrogt'n 1Il01lo:<lde Is (ooled and rt"aetnJ "ith mor... oxygo"" to prodlK\'
nitrogen djoltide, whkh l~ a brovl'O gas: 2NO(g)'" O.(g) -4 2NO:l&).
Stage 3 "lIe nilIogen dio:ddo:' l~ dissolved in watt'l to product' nitrlc Kid and mort'
rtitrogftllllOooxidr': ,1:\'0:00 .",0(1) • 2I1NO,{1IQ). NO(gI. Thenitrogen IlIODOXide is ft'USf'd to prod~ _
nitric acid.
_.
F"tgure 20 zan,
output: A pow
rely on 1e<1llile
8I.'twlorn 19$().
popko It Is pn
by 2ll2O. So, th
126
Topic"' ~
Importance of nitrogenous fertilizers
•
•
Mi.., , - .
P
All f~ th3.t conu!n nltrogm {nlt~ fntilian);or.. ~ from
3.mlJlOllh, which is prod~ using th.. 113.b<"r pt'OC'l5S. This bmiJy of fmUIzc'n
roru.ists o{Jolubll" sa.lb th3.t ("()nUln th.. nsentiaJ. elmlmu for !.><.'tter pbnt gro....th.
So, apan frbm nitrogen, Ih<"Y also cortlaln the elemental nutrients, potassium and
phosphorus. Kumples of nllrogpnous fertilizers includt':
• potassium nitrate (KNO)
• ammonium nitrat.. (NII,NOJ
• ammonium sulplut.. «NIi.lSO.)
• ammonium phospWt.. {{NHJ}'OJ
•
tlR'..
D'id
dIoxllk,
,(g)
{CO(NH):J.
~"OU
know?
The Ihree essantiaI demellb n niboga_
fertile:.<3 (oi1mgen, pot;lS.IUn and
phosphorus) have specific lu.."tions:
nitrogen is needed for gOl1(!f<ll plant
growth, phOsphorous 'so ~ for fOOt
<:leveIopment and potassiu'n plays a role
in seed formation-
"'mfrom
)
(colleni\"riy)....ned 1'.'l'K<»mpound f.. no1~
The yield of crops tlut can t.. grown 0Il11 piK1" of Lmd depmds 0lI til<" soU quality,
tho.> ctimatic" ronditions llnd t1x' a\'3ibbi1il)' of
and plant nutIimts.. Only 31% of
thP tol.lllland 11m! of lambill is ......t fur crop prodtK1ion, hut ..... can irlcn'a5Ii' the ~il'Id
by !>.1ppIying m., appropoillt.. mtollnt of nutrients in tix' form of fl"rtilizt'ts. At han'l.'St,
nutrknts are ~,,"l"d from till" soilllJld tll(')' f\l"("(j to I... tt'placed.
,,<II.,.
F9= 20
roprod~
.(8).
~nd
It'
s..ause allthfn, n\ltrierll$ ~ asrmi.al to the PWlU, th<"Sl' fmiliuTs art' a150
",d
Tho
i\
zambia depellCls on fe<tili«fs to ensure a good agricultural production
output: A potato farmen, with large commettial farm$, B tomato farmen that use
greenhouses and C _
flower farme<$!NIt export their produce to Europe all
rely QIl fertiliter'S to increase their y;eld$.
mo",.
Ilortwnm 1950 and 2000, th.. wurW popubllon ~35ol"d from 2.5 billion to 6 billion
propil". Jt D pr<"'llictrd that t!x'rt' willlX' mono than 1.5 blllklrl peopll" on the' plan'"
by 2020. So, W lW<'d for mnt'3.SN food production !us t~'l:" bout grt'ilft.
So"'l>pi(. ~
127
Effects of nitrogonous fertilizers on the environment
NitJOgenom fertiliz<.'rs are very soluble in water, which is why plants easily absorb
the nutrients. But it also means that these fertilizers are easily washw oUl of the
soil by the rain, and end up in 'tvater systems. Other consequenc" include:
1. Eutrophication: F.'(<;eSS fertilizer that is washed into rivers ~..uses algae in the
water to grow. \'/hen the algae die, they are decomposed by bact<,ria. This
activity by bacteria uses up the oxygen dissolved in water. As a result, there is
little or no oxygen left for fish or other forms of life in the riwr, so they die
due to lack of oxygen. "Iltis process is called eutrophication.
Z. Soils that are too acidic; lhis damages the structure of the soil, increases soil
.....osion and may kill soil micro-<lrganisms.
3. Crops that are more susceptible to diseases and pests: Too much availa~le
nitrogen in a plant can actually encourage diseas<'" and pests such as aphids.
4. Crop quality problems; With too much fertilizer, the crop grows too fast and
too denS<'ly. The overuse of nitrogenous fertilizers reduces the protein content
of wheat, maize and other grains. Excess
New word
potassium in the soil del"leases the
vitamin C content of fruits and wg<?tables.
eutrophication: the process of
S. Unsafe drinking walef" supplies: The
increasing "'./tnents in a water
body, SO that algal blooms
surrounding water SOurces bo'comes unsafe
suffocate the other forms of lije
to drink due to high nitrate <:onc<mlratiom.
in the water as they deplete the
oxygen
supply of the water
_ _ Nitrogenous fertilizers
-
Answ..r the follOWing questions on your own:
1. Write the thr~ reactions that take place in the Ostwald process.
Z. list the esSfiltial elements that nitrogenous fertilizers supply to plants.
3. A farmer conducts some trials on his farm. He applies diffetent amounts of
(ertililer to 10 different, but equally_sized, maize fields at the beginning of the
growing S<'ason. During the harv"t S<'ason, he measures the total mass
produced on each field. The graph below indicates his results.
a) Using the graph, determine the
optimum amount of fertilizer
8 2.5
that the farmer should apply to
each field for the following
gro"ing season.
.~~ t.5
b) The graph is divided into three
(; 1.0
sections labelled A, Band C.
What <:onclusion can the farm"'t
0.'
draw from:
o
2 2 4 5 6 7 8 9 10
i) section A of the graph
Amount
01 fertih... used per field ('-"!its)
ii) section B of the graph?
c) Give a possible explanation for
the trend shown in section C of the graph.
,
§
~
128
T,'pk7 N<>o>-meu.i,
In nalllr". carlx
diamond and Ii
Figure 21 Both
Allotrope
1l00h diamond;
atoms only, hut
MolecuJt'S that
8.'Ometrical shlI
allotrop('s. litt'
.-allffi ullotr"Pf
Graphite
·nlis form of (';IJ
cba,,·oal {)l deh
and animals.
'nte <"Moon al
of six atoms and
sllft'tS. The sher
hd" together b);
slll",1, all' ahle II
The structun
somc of its ph'• is soft and g:;'
abk· to slid'?,
• h black in co
• conduct, dft
dec·tron., in i
thR>t>d'''-1rl''
el,,,,·tron whi,
• bum. slowl}'
UB-TOPIG 5
Carbon and carbonates
.-..uyabsorb
"out of the
"""",
ulsaE' in the
.na. This
-..Jr, thE're h
.:t thE'Y diE'
In natUf(', ,'ar\¥.ln fXcUrs most commonly in olle of two ",lid lorms, nam,-Iy
diamond and graphite.
.n available
<lIS aphid~.
uoofast and
"'<OIrin contE'nt
...-.
"p:ocessof
water
. . In a
.torms oIl~e
. , dlplete the
...."
-"'llsol
~ingofthe
-=,
£78910
_1* I'icld (units)
Figure 21 Both graphite (A) and diamond (8) are made of only carbo<> atoms.
New word
Allotropes of carbon
allotropes: different structural
forms oIltle same element that
ellisl in the same physical st"'e
Both diamond and graphite' {"onsist of ,'arbon
atoIlls only, hm their stru,-tuI'-"S are- difl"re-nt .
Molen,I,,,, that "onsist of atoms 01 one dement, hut haw dilkrent st nKture~ ant!
g,..,m,·trical shap'.", (and th.'rdoIl' different physical properties) ar" call('(1
allotropc~. The property 01 an ek'm,'nt by which it can exist in t!iffer<mt lorms i~
called allotrop}".
Graphite
This rorm of ,'a,blm is commonly found as 1'001.
charcoal or dehy<iratl'd ~~<'"Ietal r<'"mains or humans
and animals.
The carbon atoms or graphit<'" at<' arrangNI in rings
of six atoms and th<'"y at"{' joinoo log<,"ther in law f1al
she<15.l'lw she<1s Ii" On 101' 01 on" anothe-' and arE'
he-ld toge-ther by wry wt'ak Ion:es. "~a r{'Wlt, Ih.....
she<1s a", abl" to slid" O"{'f on" anotht'r_
The structure- of graphite- the-r"fof{' {'xp]ains
Figure 22 The physical
SOffi{' of its physical properti{'s. GraphitE';
-structure of graphite
• is soft and !:r~as}" to tOl.ll'h, so it is us{'(\ as a luhri,ant sin..e its nat she.'ts are
abl<' to sliue 0"'" one another
• is bla.. ~ in wlour
• ,'onum1s el""tridly, whii'h is unusual for a non-nll'ta\. ' .. rbon has foUl
l'!('("trons ill its oulermost shell, but ill graphitE', ead' ,-arhon alom only uses
thr...... l'!...1rons 10 form thr...... bonds. TherE'lorE' each ,-arbon alom has a fr<...
electron which is fr...... to mo"{' and «\fry an {'le<.1ric current.
• bums slowly in air.
Diamond
Diamond Is ,.... ry RR', and IhnefOR' ""ry .."'pelIS;'..... II Is formed ..-hen gnphlll' In
the ground is subje(11'd 10f'Xlremdy high pressures and lempentw6.
This structure is '"l"f}' difffTf'TltlO thaI 01 graphill' In Ihal 1hE- cartxm aloms are
joinm I~ht'r in a ''!'r)' .strong 1l."tUhrdr;;r,1 arnngt'ml'nf. Agilin, 1M sfrtK'lU", 01
diamond exp1ilins :iOIDf' 01 ilS physical propetttts:
• l>iilmond is tlH- hilrdl"st I\illurally-om.tring ~. SmilII particif5 of dlilmoorI
UI" nnbedded in a saw 1lIadl', a drill bil or a grinding "'heeI roo- th.. JlU1TIOS'l' of
cuning. drilling or grindiflS. h «ill ;oho bI' ground
imo il po....der and ~ infO a p;>stl' thill is uSC'd
for poIishi,,& or for very finr grinding.
• P'ul'(" diamonds are colourlrss, bul sparkl.. In
lighl. This is <Iu .. 10 III{' lighl ('"nt('"ring Ih ..
cryslal rdlt'<.1t"\f from face 10 fact" inside th,crystal befm,. !>t'lng rellt'<.·Iet! but again.
• Diamunds do nOi conduct ,.1("(1ricily. lllis Is
l>l'<.<luse illl th.. d ..... uuns in the OUlermOSI shl'll
are usrd in bondillll and SU no".. is left to
transfl"l chang<'.
• lJiilmond can only bum <If extremrly high
FIgure 23 The physlcal
lempenlure:s.
stnJctI.re of gnlphiIe
Carbon monoxide
carbon rnonoxidr (C:OJ Is a ps tNl can ~ toxic 10
hwnarn in high COflCftllntions.. Although no! a
gremhousr gon. II ~ found In rebtiwty high
roncmtratiorn in !he' allll(~ lx'Qusc Ills
....
produced as <I by-pnxlul1 of prtrol and dil5d ""girll's. Figure 24 The triple oovaIent
In a c<lrbon mono.dd('" molecule, th.. <'arbon
bond in carbon monoxide
alom fOrIm threl' covaknt bonds wilh Ih.. oxygen atom. RUI, sin.... lhe ('albun
alom unly has four val.. ne<' ..1("(1rons and uxygen hil~ six va!cn.... l'lectrons. th ..
OXygl'Il atom dOnal1'S four ('Iectrons tOlhe bond: IWU ..Ie"'trons form covill"l\I
oonds ",1th Ih.. two ...I...·\rons from Ih.. "arhon atom. and Iwo form il coval.. nt
bond on th....ir own.
Formation of carbon monoxide
CarOOn mono:tidt is formo:d b)~
• Ihl' reducrion of (;Irbon dioxide by carbon: CO:(&)-+ C(s) -> 2LU(g)
(:.utlon monoxide (;In bI' Jl«"PUed in a labon.lOry by adding IIU to c:ae::O, (10
produ<."l" C;O,J. and lhom pasYnt thr CO, Q\'f:r ho!ated <'arbor! 10 reduoc'!' lhe' ps
10 CO. ih<: ps is funhl"l purififlf. to rnnQ\~ any 1r.K"1'S of aJbon dioJtidr b)'
m";rns of pota.ssiwn hydroxide (KOlil. Cubon monoxide is insolublt in ~I('\",
50 1m- fiIlilI gas pruducr i$ collectnl <1\.,.,. "'illff.
130 topK7~
• lho:' lnrompl
leis)" O.tI
('".arbon ffiOII
burnt ;rn.:! :l
tho:' a'.... ila!lM
nrbon dioD
fi~ produa
-~
Physical an
carbon mar
III l("rms of ph}
munoXldt' is:
• a culourlrss,
• sllghtly'lOlui
• "I'ry pui'lOnCl
• slightly less.
In l .... nns of chi:
monoxitlr ill:
• f1ammal*m
blutflamrlD
• 2OO(g)• ~ redurlng ..
tSoI\illr:s df'CI
oxldr 10 oop;
• CuO(s)_t
• PbO(s)+(
Activity 8
Answ{'. Iho:' IoU
I. Carh,," is.
mass numl
a) Draw tll
b) Slat" tho
2. ca,bun on
a) ExplaL>!.
b) !"am.. t!
c) Slat" t!:I
3. Qrbon!IX
a) Slatl' Hr
b) 1>Rw tl:
Inrompl~(' combuslion of carbon:
2C(s) ... O.(g) -+ tCO(g)
cartJon monoxl<k Is fonol"d whmt:'"\"r fut'! is
burnt and ther., is not enough oxygen for all
the avaJlable fuel ('arhon) to ronv\'rt 10
carboo dioxide. So, all cars, ga~ stovt$ and
fir...,; produce some amount of carbon
Il'kInOXllk as a by-pftxhKt.
• th<-
Physical and chemical properties of
carbon monoxido
In I.,.,-msof physkal properties, nrbon
monoxldl' Is:
• a colourlc:<s, tastell'SS, odourJess gas
• slightly soluble ill waH'r
• vcry poisonous
• ilighlJy less ~ lhan air.
F¥-25A~car
, l o s carbon mollOlCide gas
i'do the all, """'Plll!ie. but _ can
lleilhei see nor smell this gas.
Diel )'tIu kmW?
Carbon monoxide is d3tlgeroos
10 humans bocause ~ combol'lCS
with haemoglobin in tht blood
to form a stable COII~
-This COII~
In lenos of CMmical propntie,;:arbon
monoxldt is:
• fbmm.al)/(' in air or oxygen. and bums "ith a
bl..... fulml' 10 lorm ("limon dioxlrJl> gas
piE •• ots
the
lo<maticll. oIll11l)'l ..... ,""lIJba~
...tic:h b ......... "" CiX7\jiiif1 in the
tmodstJeam. W1lhout II.. Iha
oxygen does not Iaadl the
brain and the person
svtlocatos.
~ tCO(s} ... O,(g}-+tCO.(g)
• a r<'du(ing agem, which ml'allS that it
donates eJt'Ctrons in a chemkaJ It'actlon. for exampll', il rOOuc...,; coppl'f(1I)
oxide 10 copper and le-ad(lI) oxid€' 10 I..ad:
~ C.u()(SI + U)(gl-+ Cu (Sl'" CO,(g)
'" l'bO\sj ... C.°W..... f'b{s)+CO.W
~ Carbon allotropes and carbon monoxide
'er thl' follo"dng Questions on }'our own:
1.. Calbon is an t'!...ment on til<' Periodic 1"a.hll' with an atorni(' nomlx'f of 6 and a
mass numlwr of It.
al I)raw Ih.. l'](>("tronic stmclolt' of a carbon alom.
b) Slat.. Ih., group and period to which carbon bl'tonp.
Z. Catbonoccun;rsan~.
iii) Explain w~1 aUotlOpl"S MC'.
b) Sam., th., t"-o most CUIIlmOll allotropl5 of ;:arbon.
c) Stalt' tilret' diffl"rt'nee5 br1v.1'('1\ Ihl' I..Xl all<>Iropes naml"d in Qul"Stion 2.b).
Calbon monoxide is an oxide of calbon.
~ Stal~' thr~ physical plOp<'rtle~ of ,-arbon llwnoxld....
b) Draw Ihe dol_and_c:ross diagram for ,'ulxm moooxidt'.
s..b-ioPr5 cae-._~
131
.:.::.
Carbon dioxide
C... rbon
dio:dd~ gas
(CO) Is an ('S5l"Il.tiilJ
atmosphmc" ~s. f'\?11 tbough il only ocrup;n
b !h;tn O.OS% of th~ volume of .m. It is a
produn of rl"Spiration and wmbustion, and abo F9Jn! 26 A ~ atom and
a primary g~nhoust' gas.
two oxygen aloms: are covalently
In a I..,hl»l dioxide mo!\.'('Ule, Ih,' carbon
bonded in carbon dioxide.
atom forms strong doubl.. awal.. nt bonds with
..ach oxygt'n alom. It i' th(' must stahle oXide of ralhon.
Laboratory prepamtion of carbon dioxido gas
(""..arbon dioxIdE' can IX" pr<'p;lred in a labor;l1ory using any of Ihe methods Ih'at
follow.
PhysicaJa
properties
dioxide
In tnms of pi
nIbon dlou
• i.
a C<JIou..'1
tasleless p
• Is on~-and­
h ..aVit'r thol
• is slighllr 1
• d(l('S 1101 1l
combuSlioi
In lennsofd
I. HutiDg carbonat-=<
Soul<' a.rtlorul1.'5 will dnvrnpolM wht'n ht'atffi In gh" a solid o"'lde and nrt>on
dioxide.' gu:
• ....~s"itb
This is 1M
IIO"O"l"\"l":, •
prectplta:~
ea<:O,lSl• d1»Oh~Ul
For exam Ill!':
• CuC.O,(S)='CuO{S)+CO,(lo:)
• CacO,(S)='caOls)+CO,lg)
• 7..nCO,(S)~7.nO(s)"C(),(gj
Note
Carbonates of potassium and
90dium am very stable
molecules, :w1d $0 will 001
da:u ..pose.
tor examp6
The test 10
-,--81tJb1e the
2. Heating m ..W b)'drogen carbonates
lIydrogt'n carbo...... te:'! "ill decomposE' whftl ht'altc! 10
liquid W<lter and carbon dioxkl.- gas:
for rxamp'
• ,..aets Wilh
Ii'" a solid n.rtlorul~,
• ......,0<
hydroxide),
hydrog<'l1 n.rbon.ale ~ carbonat~ ~ waler .. n.rbon dioxi~
fOl
~xampl(':
• lNaIICtl,ls)~Na.co,(s);
3.
Rea.,Hn~ .,alcium
lip (I) + CO,lg)
carbonat., with an add
Marble chips (calcium nulxm.ate) rean with dllut\' hydrochlorlc add 10 rel..ase
carbon diaxi"","
Cleo,(S) "" 2HCJ (aqJ -->
(;alJ,(~) + 11.0(1) • c.O.W
CMbon Woxide is ~ de~ than ..ir md soluble in wat...., so in this rtlf"[hod il is
roIln;tl1'd 1))' lhe up rd dispLtn-mmt of air, as W'l"Il in FIgUn' 27 on tbf' ....xt pag<".
132
lopO< 1 ~_
..
Uses of ca
C;u-bon dioxk
I. in fi,r rXI
2. in the rna
3. as a ,('(rIg
(transfmr.
tht' R'lW'Ol
4. In baldng
fluffy as i,
S. by plants
Physical and chemical
properties of carbon
dioxide
In terms of physical properties,
carboll dioxide:
• is a (0Iour1=, otlourless and
tasteless gas
o is one-and-a-half times
j
heavier than air
• is slightly soluble in water
"'"
-
• docs not support
combustion.
Figure 27 The preparation and collection of
carbon dioxide
In t"filS of ch~mical properties, carbon dioxid..:
• r~ach with lime water (calcium dioxide "duliun) 10 give a white precipitate.
This h the identity precipitate lr::;t for carbon dioxide gas. (See below.)
However, if {"xn'ss carholl dioxid.. gas is l"'s~llhrough the solution, the while
!"""ipl!a'... will dissolve to form a {'(,lourl"," solution:
CaCO,{s)'" (:O,(g) ... IIP{l) ---> C..(IlCOJo(aq)
• dissolves in wat<'T to form a weak acidic solution of carbonic alid
for ..xampk CO,(g) ... H,o (I) ---> H,cO, (aq).
• rea.:!s with an alkalilw solution to I''''du(p a ,.all and water only
for exampk co, (g) + Na,OJI (aq) .... Na,CO, (aq) + 11,0 (I).
The test for carbon dioxide gas
Bubble the
gas throogh
a solution 01
The lime wate.turns a milky
w11rte eoiou-.
lithe gas is carbon dioxide, it will react with the
calcium hydroxide solution to produce a cak:ium
carbooate, according to this equation:
lime wate.-
CO,(g) + Ca(OH),(aq) .... CaCO,(s) + H,o(l)
(calcium
hydroxide).
Calcium carbonate is a white precipitate thaI
creates the milk;' appearance 01 the solution.
Uses of carbon dioxide
Did you know?
Carbon dioxide i~ used;
When carbon dklxlOe is cooled
and compressed, it turns into
1. in fue extinguishers
dry K:ll. which is used as a
2. in the manufa(tun- of (arbonaled drinks
relrigel'ant
3. as a refrigerant l>e<:aus<: it sublimes
(transforms dire<11y from the solid state to
the gaseous state) without leaving any residue
4. in baking (it is n-Ieas<:d by baking powder so that the bauer b<'<'Omes light and
lIuffy as it bakes)
S. by plants to produce oxygen through !Ihotosynthesis.
Manufacture of lime from limestone
I.im('Slont', Chalk and marolt' art' all fonn~ of caldum carbona1\'. 1'h~ w.......
formed by diff('"rent mt"thods, but they all $tartt'<! off as shells of sea anImals thaI
lin'd billions of ~'ean ago.
1c.co,fIi"'-"'' '
A
in
Carbon die
radiation It
gh"('S oot it
tnppro in!
h'l'ps I
rffK1 contl
;mel
•
If the con....
InC[('ased :II
.......
bumFog ;:one:
II,
'.<;00,"'1:>
burning fOl
tothe~
B
SOtnf' of lho
• Ml"ltlng,
• RIsing~.
• Changes
cooIi'>g zone
Will(' are
figure 28 A lime kiln prod".,.. ,,*,Idiilie.
Figo.n 29 A limestone and
B marble, as found in natln.
Quicklime Is manufactured from fiImostOllf' in a limt' kiln. 1lw.' by-product is
carbon dioxidE'.
Calcium carbonate (limestonl")" calcium oxidl" (quicklime) .. carbon dioxidl"
CaCo,{s)
..
CaO(s)
..
CO.(g)
arrows in thO' eq..... lion show lhallhe rt"~>on IS InTl1ibk. So, 10 incr~ till"
MnOWlt of IIlIlt' prod'ucM. the oorbon dioJeidt' mUSt bt' It"II1~ con$Umly 10
a,'Oid ractlng bad: to calcium carbonate.
When caldum oxidt is di»nlwd in watt., caldum hydroxidl" (Ca(Ofl)., auo
callt'<! slakl"d Hme) is product'<!; (;aO Is) .. 11,0 (I) ..... (;a(0l1). (aq)
~
• "''<Irm~..
...."''''
• \\'armr.'
main di~
aD
.
A>uw«'"
i)
Ii)
iii)
b) \\':11
Uses of quicklime and slaked lime
•
•
•
•
B<xh ~ USf'd in the III'al~t of acidic soils 10 help crops grow.
Quid:lirne Is IISE'd as a dr)ing:ag=t In lhe manufaetun' of ammonia.
QuldJimt Is esmlialln Ihe production of sleoel from iron or('.
Slaked lime is used to neutraliT.., adds in industrialliqui,J wasles.
Uses of limestone
Urnestone Is ~,
• to maloa> &tass (il is healed wllh sand and ~um camollale)
• lomake~rnt
• In the Vl:lraction of iron from iron ore in a hiaSI fumaC\'.
134
Yopi<' 1 No>o>--w>
~
a) Stal
~.
0""
2.
'"'
Nam~'
In a lin
3. Stale 11
••
almal
~""
up
b)
o Do>
en"
The greenhouse effect
Carbon dioxkk', ..,..ttl' \'3pout and otht'l' gaSoI"S in the atmosphom' anm." uv
radiltion from lho:' ~ to pt'M'Int~ and orann tN Nrth. As 1M nnh ~ts up, it
&i''('$ out infr.trnl ndiation ..-Ilich is ~ b)- th~ ~ I:ases.. Th~
tnpped infraR'd Bdl.atlon (in th~ form of h~at) acts as a shl~kl around the ~anh
and l<el'p5 the ~.uth warm. This phenomenon aUed the g r ~ t'ffe<:l.1ltis
d/K'! contributes to climate chang...
11 the cOllcentration of gr('('nhou~ gast'S in the atffitHph<'Tc lncwa=. tlte effeo:·t Is
Inr.·INSl'd 50 thatthc eanh Il<"<:omt.,; .oven wanner. Human aetlvltit'S, such as
bunling f~il fuds and cutting <.lown tlees for fUl'l or farmlan<.l, ha"'.. contrlbutl'd
to 1M inrrl'a.<or of l'3rlJon dimtidl' ~ .. Is, In panirular.
Som~
•
•
•
•
•
of tM ~ti'" effects of ctimat~ dt.ang~ are:
M~hing of the ~ aps ~ts in loss or habitat nur 1M pok'$.
RisinI: 'Iol'as IIood low-I)'inI: <.ilks and i5lmds.
Cha~ in r.olnfall p'lltffnS auw drouShts in
Did yo:u know?
sonw 0lU'as and tloodirtl: in ()(~.
High ...... d c:.tx.I di<»6de
Wanner, Wl'Itet" weathft" ~~ Ih~
may i"cr' I llle IIrned10use
sprt'ad of diwases sUfh as m.alarla.
eIfect and lead to gIoOOI
Warm..r was mean a loss of planl<ton. the
main dil'! of whaleos and ()th~r aquatif Jir...
........
~ Carbon monoxide, carbon dioxide and limestone
AnSW('1" Ih.. following qut'Slloru in pairs:
I. CUbon dioxide is formed from carbon monoxid.-.
a) Stal.. r..v:
i) ph~ pt~t~ of GlTbon dioJcitk
ill dll'minl pt~~ of Clrbon dic:l;(idt'
ill) uses of arbon diaxido' ps..
b) Writ.. 00.."'0 a balartcm reaction thaI sh""..." 1M bboQlory ~tlon of
carbon dioxide usinJ; cal<.ium arbonau' and dilule I ttl.
f) llescribe tIM! test for arbon dioxide gas. U'Iol' a chWlical f'<I.uation in your
answer.
2. Name tht' wa<"1ants and produ<:!s that are fonnl'd whell quicl<lime is produced
ill a lim.... kiln.
3. Stat.. two i.ndllStrialllS<'S of limestone.
4. Climat.. change is often linl<o:d to global warming.
a) I~b<." Ih.. greenhouse effl'ct.
b) Explain how the gr~hOWl' ....If...., rontnbut~ to global walUling.
0:) Ikscn~ one negatr.... impan of cIlm.u~ dung.- on "ther humans or the
nnin>nmmt.
S<"b
t, pic S eartloa a<>d...-.-. 135
Summary, revision and assessment
Summary
• ( ....ph;
....nuinso(
in rings at I
Geocral properties of the non-metals
• 'on m ..l",h i.nd~ ~II e1~mmts on 1m- Pftiodk: T~bl.~ that
~ IlOl:
ddint"d ~s
~~ls..
• Thry rom ~ pses, liquicls (J( wlkls.
• 1bry M'~ betYffi:'IJ. four MId snom ~k<'trOlU in Ihrir oulrnnosl shdls..
Hydrogta
• Ih dr..;.;..... an ~ ~ In the Labor~lory by 1m- following r..actions::
• RI'Kth~ metal .......ter ---> h}"droJddlo + hydrogm gas
• Kl'acti'~ DK"I~I. steam ---> meul oxilW. hydrogffl gas
• Reactive DK"IaI. dilut.. add ... sail .. hydrogen gas
• Ilydtogen is prepared induSlrillll)' by me~n.s of. 0"" ),.in;:, tlw
...... I,.." .1\ 01 bri ...• or .I",,,n r<'l".l1Ii Ill-:,
• lh, 1:.'0 can be p.epan:d. in the l~boratory by the following reactions:
• the thennal catalytic decomposition of !'ut=lom chlmatc
• the decompositlun of hydrogen p('roxiu(',
• Oxygen is l',epar{'{,\ industrially by th(' I ",It 0"'1.l1 "hi ill"ti.." .. I ,.;"
• I)/,,u,,1s an allotrope of oxygen, h is found in lh" ozon" layN in the
aunOSl'hNe, and prOlms the earth from tlte sun', harmful ultraviolet r;l.)'S.
• \\ ....... is an oxidr of hydrog...n.
Nitrogen
• 'lim.:.... gas is obtained from Ihe air by fractional distillation of liquid ~ir.
0rW' of its mosl important uses is 10 ma~ ","monia• \n.morti.. is prrpared industrially by mr;uu of llw 11,.1..,.. I......·".
• Ammonium.al1S either dKmnlJ'lM or sublinw (cMnges dill'Ct1y from a solid to
~ gas) when they are tINted.
• ,,In.....d rl'KtS ..ith ammoni.a to tonn Ih.. tenilir,rr, ammonium nil1'llle,
• Nilric' add is Industrially ~ by the.' Ihl" ,d" pO'''' ......
• 'il ru;:.'nnn. 1..'1; 1i/t'T'\ conuin lhe.' essrntilll rlrmcnts for brtter pbnt
~nd
ninogm).
l)u..wo4
high prrssa
"'hic'h m.W
• I .. rboo ...
COIlC\"Ilt tIoII
tl1f' inmmpld;
• ( ..rl..." d.
W:>ontol)' b<'
""~cting caldl
• Ihli.l.l"n ill
quicklim.. \0
Revision e)
I.
OXygen
growth lpous:sium. pbosphorus
•
c.Jea", Un- ~
a) Name ltll
b) D\'SCrihr
oxygen
2. [{('Spiralion;
EXIIL1in hooo
3. TIt" Ilabe:r po
a)
Writ~ a
til
m"ans at
bl SIiII.. ,,",'0
of Ih.. Ira
4. D6cr11Jo.> bril
starting ..it!:
5. Carbon is .. I
a) Write doo
<bo\.' th¥
b) Which pi
has this
~
c) DWnond
M~lopl
Carbon and carbonates
• ( .. rb.... ru..IWO nuin ..n,,' ...,....: graphlt.. ;ond iliamonlL
... ""'".
d) Qukkli,..
-~
136
lop!<' 7 10I<'<nistsy) Summary, m1...... ...., .............1
•
dcfinro as
.....
• (, r;.!.h ilo' is <Xmllnon!y found as soot, char<x".! or dt'hydrat<-d skelt'tal
rt'lllaius of hUlIlans and animals. l1,e <-arbon atoms of graph!\{' ar<' arranged
in rings of six aloms and tht')' art' joinro togNht'r in large flal sheets.
• ! li""'o",1 is fOllned wht'n graphit{· in the ground i!; subjectro 10 extremely
high pressures and tempt'raturf's. It has a very strong tetraht'<!ral slr.uelme,
whid' makt'S diamond one of the hard<-:<I sllbstann'S on earth.
• (''''bUlI
i."" is a gas that can IX' IOxic to humans in high
nHKentraliollS. It is formed by the I'<'du{-tion of carhon dioxide by carbon, or
the incomplete t-omb~li{)n of carlxm.
• ( .. rl..." dl ..... lde ga,; is an ",sential atmospheric gas. It can be l;repared in thc
laboratory by hcaling <-arbonates, heating metal hydrogen car!>onat"', or by
r<'at"ling <-akium ,-a<lx",at" wilh an acid.
• I)"i. klilt,.. is prodll<x"<J in a lime kiln, wh,:re limeston" is hurnt 10 form
'1ukklinw (CaU) and carbon dioxid",.
m"".....
Revision exercises
1. Clean, dry air ,-ontairu; about 79% by volume of nitrogen.
a) Nam'" th'" gaSl'S that make up Ih'" r"'rllaining 210M> by volume of air.
(2)1
b) n''St-rilx' th,' tnt that you would ,-any out to confirm th,' pre",,,,-e of
oxygen.
(I)"
2. Respirat ion and "'sling aJ"(' chemical proc{'SS\'S that involve oxygen.
Explain how oxygen takes part ill each of these rea<1ions.
(2)-1.1'
3. The Haber prOCt'Ss makes use of a 1('V('fsible rea,iio!l to mak'" ammonia.
a) \'/rite a halann"<J !'<JuaUon thai ,how, how ammonia is puxlm'ed by
means of tile IlalJer pro<-..ss.
(:1)1
b) 5taW 1WO nmdiliollS whid', tog<.'th"r with pr"""re, also alfe("! the raW
of Ihe "'a<iion.
(2) \11
01, fIt>scribe briefly how you would prepaJ"(' crystals of ammonium sulphat"',
starting with ammonia.
(]) \1'
_ a solid to
lli!Iat~_
S. Carbon is a typical non-fiNal.
a) Wrile down Oil<' physkal prol"'rty and one ch~mkal propt'rty that
show Ihal the statemenl ab",'" is 1m...
(2)(
h) Which propl'rty of carbon is typical of a metal? Explain why ",,11<>11
has this property.
(2) \1'
c) Diamond and graphite are allotropes. Explain whal the wrm
Ma!lO!rOpe" means.
(2)l
d) Quicklime is used a drying agent in the manufactur'" of ammonia, and is
also needed to produce steel from iron ore. Explain how quicklime I,
pf(l<lu,ro in a lime kiln. fllllStrale }~IUI answer with a ch",mica! equation. (5)\
Topi<" 7 tCh{'fIIi,ny) Summary, revision aod =Olent
137
Summary, revision and assessment continued
6. Coosidn a gh'el ~"Ol\lm~ of watn.
a) "'allH' 1M two fflol1l('Tll5 from "'hkh "llteJ Is nudco.
b) T.tp water Is dt;an. but no! pIm'. F~in Whal this m('ans.
e) NanH' t..... lndustrial ~ of watCT.
d) Dncri.~ th~ ehenuo:;llt~ of 1\'ittCl.
(2)i..
(2)'
'"
(2)i..
1301
Assessment exercises
I. Ilydrogen Ciln be mw in th(' laboratory by dripping dilU1(' ~ulphuric and
onto zinc III a flask.
a) Writ(' a chClTlkal equation for this ,(';action.
(2)1
b) Explain whal you would obs<:'rv(' ilt till' flask.
(1)1
c) The gas is culltt'tl'd by bubbling illhrough watl'r into a gas jar,
What doe5 this Indicate about th(' properties of thp gil$?
<.I) !><'scrIb!: hoW you would test for h)'drogen gas,
2. II nitrogenous ft'rtiliu>r con.Uins thl'l'l' main ('1('111<'111. that plants nffd
for hl.-allh)· growth.
ill) Nam~ tM thl'l'l' elemt'flU.
,I>
b) J)1'5cri~ th~ ,o~ neh rieIDffit plays In pUnt growth.
e) Which of th~ thll:'l:' cltments :an pn;r.'idro by th<:' following fl"rtlllzt'n:
;) ammonium phosphat.,
(1) \.
ii) po{~um nltnf~
(I) \.
iii) ammonium suJphatl'?
(I) \"
d) Writ~ down 1M formula for ~Kh of tM fMiliUTs in Question 2..e). (3) \p
,'.
roo ....
3. £xpWn h",,'
, ould <k-sign an pxpeTirn<'l1l 10 obuin
from a hydrogt'n peroxid(' solution,
~n
(4) \0
'I, LimC':Stonl' is quarrll'd on a larg(' sca.1~.
a) Which el('ments dOC'S lime'\ton(' contain?
( I)io.
h) Much of the quarrit'd limeston... I. mn\,('rted to quickIim(' for uS(' in
th(' S!ecllndustry,
i) State th(' "hernical nam.. for quicklime,
(1)1
ii) 1)('scrl!J(> how quicklime i~ rnaill' from t h.. IIrn.-ston..,
(2) \,.
e) I'owdC'IC'd liml"sIone is uwd 10 impn;r.~ the >\'aWl' quality in ;roCidi/led lam
i) Givt' .. po:sslbk f'USOO why th~ water in th~ lakes would ha\'('
b«ome aciIll6l'd.
(I~
Ii) 1)('Scri~, ming a chmlical <,<!Wltion, bow ~ ~ can h~lp in
Wfltding t~ pI! ~ of Kidi6fti watCT bodies..
(3) \"
iii) ExplWl why you lhim.: liInr$Ior>e is usM in 1M ~der"ed form,
nlho:1' Ihiltllurnps..
(I~
Total: 30 marks
-
11o.. d '90' IS
'
S• 1"""1,
TOPIC
\'
,
"
,
:
','
Organic chemistry
, (",
,
'"'' .. "r
{2,..
(2)\
(2)(
(2)"
[30[
"
,
Sub-topic
'
saturated and
unsaturated
hydrocarbons
o Describe an organic comp:>Und.
o Describe a hydrocarbon.
o Illustrate and I13ITl!lt~ structures of the aliphatic alkanes up
to fiV<! carbon atoms.
o Demonstrate the structures of isomers and their names.
o Describe fractional distillation 01 petroleum (crude oiQ.
o Describe the uses of t~ fractions of crude oB.
o Describe the c~mical properties of alkanes.
o Account for the apparent non-reactivity of alkanes as
compared to other organic compounds.
• Illustrate unsaturation in alkenes.
• Describe and name the structures of the alkenes up to five
carbon atoms.
• Demonstrate the structures of isomers of alkenes.
• Describe the chemical properties 01 alkenes.
• Illustrate the differences and similarities between saturated
and unsaturated hydrocarbons.
• Describe the chemical tests for unsaturated hydrocarbons
(alkenes).
• Describe the uses of alkenes.
Homologoos
series
• Describe the homologous series.
• Describe the geooral characteristics of holTlOlogues
,,,
(2)t
(2)\1'
(1)'"
-
( l){
I'"
(I) \11
(1) \11
(I) \n
(3)\1'
(members).
(-1) \n
(IIi>.
•
--
'"
(2)\1'
..
(1)\
(l)\
lO marks
Describe the chemical composition of an alcohol.
Describe and name structures of primary aicohols up to five
carbon atoms.
Demonstrate isomerfsm in alcohols.
Describe the formation of aloohols.
Describe the chem;cal properties 01 alcohols.
Describe the uses of aloohols.
Descritle and name structures of carbollylic acids up to fiV<!
carbon atoms.
Describe the formation ol cal'boxylic acids.
Demonstrate the chemical properties 01 carboxylic acids.
Describe the uses of carbollylic acids.
Describe and name the structures of esters up to five carbon
atoms .
Describe the chemical properties of esters.
Describe the uses of esters and relate the uses to properties.
TopiC II {lrgank <homin'Y
139
• I'1es libe rnacromolecuIlI (poIynws)..
• be S)'111l1Ctie rra:<O,oolecl.les
the fofmatJon 01 poIyaIkenes.
· 0 'fypl jos
• Oesu ibe the formation 01 nylon and Teryklne..
• Ditl& Cl,liatt! bel.. OOi I the stJut:tae of nylon and TlW)'lene.
• 0 I • ibe typica!1.I5eS 01 plastic$ and S)'l'1l1fl'lic fibre&.
• Describe the biodegiadability of syntheti<.: fibres.
• Describe natural macrornolec:uIe_
• Describe compr;>$itiOn of carbohydrates.
• Identify linkages in starch, proteins aOO fats.
• 0
• oescme
E\-ny living ....
found In e-""'l
stin 10 Ih..- roo
Ct:lnulnfn ......
• Relate linkages in synthetic aOO natural polymers.
• ~ribe hydrolysis of fats (saponification).
-,Idanlily the products of the tlydrotys;s 01 starch and proteins.
---,:0
Starter activity 1
Ans"..". th" following qU<":SlloliS in pairs, and Ihm di'ICUSS a:; a dass:
I. AU thing m.:tU"r b ma<le up of long chains of clibon alOms joined logether.
a) Writ" dm-"Tl Ih... ch<'mi<"al symbol for 11K> eIem..m <'arbon.
b) !low many val~ ~ons doI'5 an atom of cart.>n ha,...?
c) How man}' chMnlal bonds can carbon maL.- "ith other atoms?
2. Carbon and h}xlrogm bond to form U~ ~"" 1ItethaD<". 01,.
a) NaIlX' the' t}'JX' of chemKaI bond that forms 1Jo:tv,"l't'll a h)'drogm and a
carbon alom.
b) Desaibt how this bond f<:>mn.
3. What is Ihe dlff.......m ..... ~'A"ffI1 an Ofgilnt<" suhslanc<: and an inOl'gank"
SUbslarn:t'?
Starter activity 2
Answ~r
Ih" following questions in pairs, and Ih<.'n tii\{US'i as a class:
1. Loo}; afound you and nutice how many things art'" made hom some type of
pla:;tic.
a) Nam... some Items that arc mad<- of I'lastll.' that )"OU use ......·ef)" day.
b) no you thlnt aillhe plastic prod.....ls are made up of Ihl" .same
of
I'bSlic matNbl? Gi'.... a reason for YOUI aru'A"1:'I_
cl Why are pla!.tk: produc:tt so much ~ USl'tuI than products I1UIdt' from:
i) gbss?
iiI metal?
2. Plastic is ill poUulanl.
a) Wh.at do you und<"lsUnd b)·th\: SUtE'ment abo'I.... ?
b) I low dol'5 plastic wast.. impal"'l on our tn,1ronmoml?
tw
140
Topi<lI OrpRlc<bnr.lolfy
Organic «
Organic com;>
C<lIrbon, but ~u
Tbt'y foon 11><"
orpnlsms.
C'.aJbon. is f""
Taliit', so it has Ii
thM Ihl" carllo:<l
bonds wilh Olhl
ht' single, doublo
Carbon ato",
otht'T, wflll-It ca
ur rtng structu"
togt'lhl't to for::
Wf" call thiS urn.
Carbon
r.l.."l •
...k'ml'llIS 10
rna.
molK\l1<"s.. TIl..,
Imotm organic
cht'mical propr.
W... cbsslf}' ""
SUB-TOPIC 1
Saturated and unsaturated
hydrocarbons
£'"('1')' living organism is madt' up of organic mol<"CUll!$. Orpnic mole<:u16 are .lIW
found in every aspe('1 of our livt's, from thC' prolein, Ihat m:lke up our h:lir :lnd
skin to the fo.,d, that we eat. and from tlJr duthes that we "'ear to the plastic
cOfllaine" "'" ,torC' foooJ in.
New words;
orgarlic~
~ that 0lltUin the
. , . . . cartIon, exceptio.carbon oxides or c:.vboililles
catetIation: the ~ of an
element to itself tttrough
covlllent bonds to form chain or
proteins.
""•
F".gwe 1 Olga .. dlemicaI:s are foln:l in every
~ 01 our lives.
Organic compounds
.lnd a
Organic compounds all contain the clement,
Glrbon, but udude any oxidn and GlrbonatM.
lb<')' form It... building blocb ol;olllivlng
·C·
...
•
•
·c·•
F"1ljlUI'e 2 The possible dot-ando;rO$$ diagrams 01 i!I carbon
."""
•
•
...,n.""
•
•
•
0aI.. . . , . _ ......"
arbon is found in Group IV of the ~
nbI<'. ~ il hits four ~ eknrom. 11th means
•
• • •
that til<' rnrlJon atom will form fourcm-aJent
bonds wilh other atoms, although the bonds may
•
• •
I,.. sIngle, double or triple COValt'l11 bond,.
Carbun atoms easily fom] bonds wilh each
Fogure 3 Adjacent carbon
othC't, which C;u"l result in 10llg chain "ru<1ures
atoms bond 10 !omllong chain
Of rlng '1ru<1UJn. \\'hen arbon almm lin!o;
strue:tures. In Go'ade 12, we will
togedl('1' 10 form 1hC'sr COViIIC'nt l'hairu; or rings,
~ Lewis diaiji_'l$ 10 illustrate
.... call this Iinb.g(' ClIlenation.
valence elecbOll$ in 019'" lie
(~rbnn can also form bonds ..ilh otlwr
elements 10 mal:t wry complC'x organic
m.,!N1.lI('5. ThesE' prupl"rtit'S of IhC' cartx>lI atom haw' f('5U\tt'd in Uvt'l 10 mill iun
!o;nnwn organic mO!1'<.1..lies, each with Ih own unJqut' namf'. and ph)',;lcal and
chC'mkal properties.
We classify organic moiKUlC'S Into groups or familiO'S ;w,:nx<!ing to thC'l. slru<1ul'3.
-C:C:C:C'
-
-
Hydrocarbons
Structun
TIH- simpl"l org:anic: 1lI01f,',Il" form ~ famlIy of ('(XnlX'Uf'ds a~ lhe
h)'dnK:arbo<u. Thc'y ~l\" mU urof only h)-.;Lrogen and arbon ~toms.
H}-dnxarbons Me WI)' usduI and pIzy ~ role in ow nTT}WY live.. Sornl' ~
;tl\" gao cyl..illlk-rs of bo.tIanr load propilI'lf' (U'(i fuel), petrol. diesel fufol, Jl'U3ffin oil for
~ting and oil lamps, ;md ",ndln (hea"y h}ulQ('illbon paraffin ","ax).
llH- >implesl
IlJOknIIa! fo
IWO arbon ~
USC' thor fo
SlI"J1I: !)Mn
Newwonls
----_
~.",
_.-
"'~
hydrocarbon: an organic
molecule that oontains ooty
hydI .....g e" and carbon atOll'lS
IlI"OI'I'\3tic hydrocaI'bon: a
hydIocabull in whictl the
carbon and 1'rpdI0000l atoms 1ft
.iOi-l to!Jelt* in a closed mg
~
aliphatic. hfdl _'boie a
hydI ...... boi' in wIw;:h the
....
carbon and h'JdI """" I atoms are
jDined 1Qgethel in 6tJ <W\tIt
FlQUfe 4 Hydrocarbons are the aimplest family of
organic compounds, but one of the most
important energy sources on earth.
53tur3ted 11yOroc:artlon:
hydrocarbons in whCh the
chain of carbon atoms contains
~ngJe bonds only
unsatur.lted hydrocarbon:
hyOOx:;vbons in wtloch the
chain of carbon aIo:ns contains
at least one dOutolt Qr ~
Hydrocarbon (ompounds l.f~ classified as
afOlDatil; Of aliphatic. Aromatic hydrocarbons
form ~ ring stnKture. 1lw aliphatic
alkanes: a faniy aI satln:ed
brdroarbom form Ion8 chaln stL'UCture.
hydIocabullS that t.w only
llH- aliphatic h}Wocl.!bom an' furtht:r
songIe bends
the
dusilil>d as SOIturated and unsaturat«l. A
.~
satuntted h)'dro!:arbon cont~ns only singk'
a/kene$; a t.niIy aI
bonds betwffn the carbon ~toms, whik' an
contain at least one 00ubIe
unsatur1lted hydrOQ.rbon ront~lns ~t least one
double bonel (or triple bond) between the
alkynes: a family of
carbon atoms.
unsaturated hydroo::arbons that
The saturated hydroclorbons form a family uf
contain at least one triple
cumpoullds (ailed albnn, whlll' th,.
umaturat~od hydrocarbons form two familin of
compounds' th., a1kenes (whkh contain double bonds) and the otlkyon (which
contain tripl., bonds).
""""
"""'"
tJet,.,...
--""'"'""""
""'"'""""
142
Topio<'OIpDi<.!
,,,'
Slq> 2: ldmt
bond
d,
• If I
d,
o.
5t.,. 3: If the
•in thl
Structures and names of the hydrocarbons
--,.,
..-noll for
--_."'"
.~
Th", simplest ll1kaM - lDf'thamr ronSIStS of on<' carbon alom and has th..
mol«uW fonn..u... ClI," T1w ~ mmI,,"" of thl$ Iilmily - tt~ - coruim of
two allbon ..toms md has u.., rnc>lof<:'ulllr formula C} 1._
u~ the> foUowing urps to namII" any hydronrlJon:
5kp I: Ol'1mnlOf' thl" prmx (thr first 1Mr1) d. till' naIDI!. b y ~thl- numbo' d.
cwboo atoms in thr b1go"U main in thr nrlecuJe. F.-:tl nwnbo.'r d. arbon
atoms tOC.lsptJi""" to a O'flilin prt'fIx. n....lir.>t li\"l' ME' s/loool.... in thr W>W.
~
~
2
eth-
3
prop-
:4._""]
~
5
pent
Step 2: ldl'ntify If thew an' only liingl.. bonds, or if there Is a doublt' or tripl..
bond. n,ls will dc!crminl' lilt' suffix (lh .. last part of tilt· n,,"'<').
~ If tl1('r(' lIt(' only single bonds In Ill'.' chain, the naml' !'nds in .... nl'.
• If th... n- is a double bond In tl1(' chain, th" nam", ends in -ene.
• If 11I('1\' is a triple bond In tll(' chain, til.. nam....nds in »'n... (NoI/:": In
(;radt' 12, W(' wiJl only ronsioo single and double carbon bonds.)
Sl:." 3: If Ihl'ff' is .. doubk> bond In the carbon chain, lhnl number tlw- arbon
atoms In 1m-longest chain. StaN numOOing from tho:' rod tlul will U'!iU11
in 1M doubl", bond bring dmer to thot- start of 1M cb.lln.
,oro_
"
~~-"
C,H.
C,H.
"
", ",
H-t~-H
CH,CH,
""
CH,CH,CH,
~ ~ ~
H- 4-?-H
~ H H
C.H..
H H H H
O-<\-.!--{--<-"
~ ~
rwhkh
Pt!' ,ta Ie
C,H",
H
~
H
o-<\-t{
,,
"l
~
i'l
i'l
~1r
H
Slob"'"
i'l
I
»now<d an<I ........._
CH,~CH,CH.or
CH,
),CH,
CH,CH~.CH,CH.
orCH
J,CH,
"rd,o<.. bocu
143
llte foUCMing u
Step 1: Idl'ntif,..
Tht alkanes' moll!CUlar formulas form a palttm that can boo d=lbN by Iht>
g~a1 formula, c,,1I:a.r
"="'"
Ste·p 2.: Ul"lnnm
Step 3: Idl'nt.....·
""",,w
Stt'p 4: Coum d
for thl' b
w ....
St"p 1 ~ Me four nrbon at0ID5 in Ihc longest chain.
Step 2 The prdix is but_.
Step 3 Only single carbon bonds present.
Step 4 '1111' 5uffix Is -<lrll'.
TherefOl"€', the name is butane.
Stl'p 5: NumhI'J
all.:rl (bIl
t"l,d lhat
carhon ..
Stt'p (" ·li> WliI"
of brand
Isomers
l.somen al"(' organic compounds that can have
the sam(' molecular formula, but have different
SIructur3.l formulas. For eumpl", the organic
compounds in F,gur" oS <ll"e Isomers bKaw.e both
ha,..., th.. moI«"Uw formula, c.n.... but their
stmctur'rs al'l" diffetmt. Their diffl'Rnt .tlUCtul'l"S
..ill no=lt in each compound having diffrrent
propnties. Thet' two compounds ~ caIW
--
;-...
amainctm.
~
_ ~ H
HHHH
H-t-t-.J-t-H
it
~ ~ ~
H
IH
H-t-C-t-H
I~ ~
1\
Worked e
New words
iso<'nen.: ocgan;c cotnpOIM'lds
..mtl tile same rr<lIeO .,.,.
Iorm.JIa. but diIlto.. ,t $IUCttnI
NallW'lhe
l
aU<yl grtq>: a si'lgIIt cartIon
atom or ctm. d WIgle-bond
cartIon aklms that joon up with
Rememllat
There is aIw3ys a hypllen (-J
bIItween a BJrT1ber and a Jett..- in
the name_ The name is writtE'n as
one WOfd with no !;)ao8S
2-mothylpropane
Rgurc 5 loon-.. of C.H.. are butane and 2·mllthylpropane
L Theft';an,
2. Singlt'
l. There is a bi
-I. Thl' bRndIl
S. We numJltoi
nrbon-aIl:Jlj
butanu
StTU(\ural isomer.; lleneraUy ILlY(" different chl'mk,ll and physicaf pt"opc'ltln,
though tilt")' haw· tht> SlIml' ffi<,k-cular formula.
Activity 1
c."'c.'n
Naming branched chain hydrocarbons
A bnnchN chain ilydrO("<ll"bon fomu whcn u~ of Ihl' hydlogm atums thaI Is
bonded to a carbon atOl1l is rrplacnI. by a carbon atom, or a cb&in of carbon
atoms. This branch is nlkd an al1.--yi group and b ropresmted by -R In 1M
S1lUCtunl formula. 1lM' alkyl group or bnnch is na.rnrd b)' replacing thl' suffix-ant"
..ith -)1. The!Jranctl na.ml' Ihm bf'ocomes a prttix to the main chain rnltm'.
the foH,,",
I. I1dine the I~
2. Ura... Ihe s:n
a) butanE'
3. Two of thl' s:
ill N~mE' lilt'
bl t:XpWn'"
All~ ..."('r
n,., following st~ nn ~ used In ""......... br;mchrd dl~n hy<1rocMbon:
51." I: Identify thl' longest corulnllOUs chain of arbon .,COIm and n>\lnt th..
numoo of carbon aloms In it.
SIC:-p 2: llt't('rmin(' th(' prriix of ,hI' O;tID".
Step :1: Identify If lh",(' art' only single bonds, or if tMw is a douhl(' Or triple
bond, to urlNminl." tht'
~\lffix.
St... p 4: Count tI](' number of lOlrbon atoms In lhp branch. Ol'tem,i"e th(' plcfix
for tht" branch 3CCOCtlin8 10 Ihl' llnmbe'r 01 ""bons and lBI.' -r' as tll..
suffix.
Stop S: Numbn" til(' nIbon ",toms in tho- main chain 10~' 11K' position of th<all,'yl (braJl('1l1 gJOUp In 1M main carbon chain. Stan numbmng from Ih..
md lhal ...'ill f=>.ll in tllf' aLL)'1 groups bfoin& on the lOWeR n\lmbrn-d
cuoon aloms on Ih.. main ,"hain.
St..p 6: To wrilt· down th(' ,mmf', w,' start by wfiling duwll til.. position and nallle
of branch.
......,.,
"""""
up with
Answl'"r
I.
~ art'
four carbon aloms in 1M longest chain: but-.
2. Slnglfolx>mhonly:-~
3. 1llftto is a brand! rom.isI:ing of a ~ c.ubr.wl"tom: mall)"!
4. TM branch 1$ on the S«Ond arbon atom: 2-~hI1S. \'IItt num"". from IhIt righiiO get thtt blanch OIllhtt 10...61 numbttrttd
arbon-atom: 2-mt'th)'lbulalH'
~ Names and structures of hydrocarbons
Arn...tt. tm, foUowing questions on
"'''
.
~'OUJ own:
I. 1}Ifbntt t ..... tttnn ·h~-dronrllon·.
2. nnw thtt suunura! fonnw for:
31 bu!arH'
bl 2-mttthyl-propilK"
co) propantt
3. T...o of thtt ~I'\ICtUJttS you. drt·... in Qut-rtlon 2 ~~ isotIII'TS_
~) N~m .. ,hI' ''''0 i'iOm<"O.
h) F.Jl"I~in why tllese two mrnpounds ~r.. l<omE.'rs.
In summary, the-
Fractional distillation of petroleum
o Iht hIgher in I
• thfo IC'n voU.llJ
Fossil fuels
~roIeum is a
This nK'=~ it is Iht rmlaJn~ of pLmU and anlm;o1s tlut
!h'rd milliorui of }~iiln ~.l.:.oIl md ""Iurlil ps all' ~ f",,"1 furi'lo.
tonsil
fu~1.
Uses of the fI
New words
_.
FIgure 6 Fossil fuels are extracled from earth
through offshonl drilling (natural gas and crude
oil) or drilled and pumped from the ground
(crude ad) or mined from the swface of the
.....
d>osel or gas 01
mineraVl~
""'"
ea'....... 1eflt of aude of that has
Refining crude oil
(:rudo.' pl"Irok.>um <>ills a mixture of hundrM of
different ~l"'$ of Ol'giilnK rom(X>WIds. MO'lOI of
lhew an- hydrtX'1lrbons. TM diffnenl t)"Jl'e5 of
("01Ilpoumh in tht mlXIUI'f' an- called fraction$.
EMh hanlon lus iii liS _n phyYc:a1
and chemical pn:>ptrtll'$ and a p;uticular
US(', so il is n~ry to $I:'fIO'Iate thefran ions from ont another in the- CT\lde
oll. This is called I'f'lin in~ and it is C1lrtit'<1
ow by Ihe pro<:ess of franional
dIstillation.
Hgur.. 7 shows a .Imp!e refmery 10W(']".
• The firsl Swp is 10 ht'at the CT\lde oil:
the fraction with Iht Jowl'S1 boiling
point (smallpst mol«ulf'S) boils firsl, so
Its gases ris<' to the top of Ihe 10W('I.
• nw bIgI" the molKul~. the 101\...,.. the
ga$ riles op lhe to"'...,... TIlt fRnions
fhen ronde~:JI dlfft'Tftll inTis in the
fO"'·fi
fossil fuel: a fuellhat was
10rmed millions of years ago
from the remaios of plants and
animals. but wbich is • I n'ble
to tunans lor lXInSUn'Iption in
lhe Pi
.1
lraction (c:rucIIe oil): _
COlrt3in dlel.ic:al ald phy$ir;lII
Piopel'ties. ald mo$l;:"
sepat3l:ed from the oct.Ii aeticx IS SO that it cal be
..........
_..
t+- peoc:c..
""""""
Answ~r
C",-C ..
1.
--~
C,Ao
Ulo'ieal8
e.-C:
"""".
...~
md:J1l' pumped iiI"':Jy.
FIgUnI7 The ler.lii9
Activity 2
C,-C'l
plOt:e$$
oil
the foIl"""
l)(Ofinelh~t",
2. f.xplain wh,',
3. Gh"t'n the fal:
dodeca~
Ie"
i1) Ihe ordC'!:.
roh.mn en
b) which all.i
co) which aJ.I..l;
-...
~
In summ:uy, th"larg\"r tho:' molecule of ~ fraction:
• the' high"" its boiling point
• theirs. ~Iy It win flow
• 1M Ins ,"Olati... il will be
• the 1= ..nily il will burn.
Uses of the fractions
liquefied petroleum gas
fuel for cooking
-'"
fUel for petrol-based vehicles
petrol or gasoline
petrochemicaJs, plastics.
"""""
ken: ...... or parafIio
, 1-18
)et fuel. peuoc:hernicaIs
dieMl or gas oil
''-20
,...,.
luellor 6
ship fuel,
0' hued vehicles
~ stillioo IS
ca·,ef.~.poIish
road surlaceG,
roof_lg
Did you know?
-'
At petrol stations in :tOme countries, you can Choose
betw~ leaded
and <mleaded petroL Loaded petrol
•
contains letraethy1laad, II lead additive. Lead is a
pollutant !hat is <Jangerous to the environment and
CXltJrltries have
bar>rMd the use oIle<1dod pooIn:ll. am so It
used to:tay.lambia stopped lIiSO"ljl '-lad
petrol r. 2008. By lOll, AlgeRa was the only MIcan
CCIUnlr'y SliI ~ leaded petrol.
Iu'r'Ian&. For ItIIs n!8$OI't, most
eo.w"c""
IS"'"
•
•
.~
.':
~ Fractional distillation of peb oleum
-
AnsWfT th.. follOl'>inll qU('SI'ons on youl 0"":
I. l)(>fin.. th,. wrm "fractional distillation".
2. F.xplaln why <TIul.. oU must undergo fra("llonal distillation.
3. (ijV"ll the following alkanes: "onall.. (C,II,.,>. triaoontan(' (C",",) and
dod'"<"an(' (C"II"j. dl't .. rrnin ..:
a) th,. order In which thl"}' would llf' wlll'<1oo in II frao:titmal dhtillalion
rolumn (from bottom 10 lop)
b) which ~lbnt' could I)(' usOO in pt'Ifol
co) whkh ~lbnt' mighf ~ used in Iht' nunuf<>ctu~ of I'I.ulin..
~ubt"'lloo
~
147
""""" -..
Chemical properties
A1bllt'$ an:' gt'Ol'nUy wln:'attl~"" bKausr UN' bonds 1wt""Hfl tM GUbon alomS a.t
subk" and Itw moItrults bel; a sptOfic site of chtmk<tlaIUC!.:. weh;lS a
fwKt~1 group. Bul Ihrir chtmic;Jl proptrtits anow thtm 10 underxo lour t}llts
of .t'iKlions, as disc:ulo5ell bclow.
New""'"
,. Combustion
cnc:king: the p....:ess of
No reac:tion ocnm; when an "ll,:an.. ;'; mixl"d
with oxygen al mom ternp"!"'''ur.., bulw!len"
hrne or spark is added, a highly exolheIll1 ie
combustion rea"lion tal((Os plan' to prooun>
w~tN and ,-a,IxHl dloxid(>:
Alkal1
0, i (:0: .. ",u .. h('al
~~~ampl(': f:1I
20, } CO,'" 211,0 I h('at
11,... h...atlhal is prodocE'd Is tlK' r('ason why
albnts make such XOlkl :iOur«':S of fuel.
breaI<rog down monl (X)I'nplftx
moleo::Ules inlO $impleI
"""""'"
Note
The I'\lJrflt- 01 hydrogen 8t1d
carbon aloms must be
conserved in the aacl<irog
.~
2. Cracking
Old you knO\'l?
pmn'Ss of brl'UiI18 down more rompl..,.
mok'c:uln into simplft ones, I' nlled crKkinll:.
In oil mining. c:rx1:ing Is used to brl'.u: Iongn.
chain h~"droGuboruinto ~f'f<hain
1'lI('
n. ~ ........, of petrol .. <::Il.Ide
oil Is too Wde lO mee1 the
demands of the """"d.
~
ehaon hydi....OOIS havelO b6
h~'liroc:;arbons..
~loi","
'K":'"
,
tf----.C-tl
H H
tl
<J!!!""
-?-H-Y-H
HHH
~
tl
~
..lOlha",
"
•
;c=C-y-tl
tl
,11H
_1.-
"'"
..,..,......'
Fogure 8 PosS'1M products lonned wtlen tlutane Is crad<.ed
148
10pi< II
Otpnlr.-.,
bromint (ill). in WI
c:ttIorimted md bnD
lMtfwlt«J1Jlog:o.
If more chlorim' is ..
•.
ala}'~dca
4. Steam reforrr
IlydrDgi'n ga.s is a II:lI
pIOCfiS uses th.. rutI
p«"Ssures In the- ~
(;11. (gl ... Up (g) ~
~
Answ~r
the follO'O<inl
I. f.xplaln "'hy a!Ii:l
othff organic: CllI
2. Wrlt.. lN.bndtdc
typt of rtxtior!
a) ~l1(''' d1JIr
b) metlwt
sa
t:) propan
m"
anthe
In this ..... y, som.. llght pE"lrot..... rn produn.
...,;un 01 avaiabIe fuel
.uch as I.PG gas ~ ptIto1 nn bt" produc:nl
!10m hea~il"I crud<' 011 fIOK"!;ons, soch as rh(' ga. oils Of bitumen. 110......."('1". singl('
unique reactiom do not
;nlh(' cradlng prOCtsS, lb(' hydmnrbon moltrult'S
ale broken up in a fairly random way to produce lII;xturt'S of small...,.
hyd.ocalbons, some of wllk'h han' earlxm_carlxm dOllbk h()nd~ Som<.1imes
h}'lirogen gas (H,) i. also produ<'ed when a carbon-hydWj.;<"n Ix",d is bmken.
Som<" exampl... a...:
H
H
It
tl
...
3. Substitution
The alkanes
The alkenes
An alkene has a dooiI
two carbon aloms.. A
in which ..ach c:aIba
(single) bonds to odi
alkanes, All:enes ~
each of the carbon I'
double bond only b.;
other aloms.
"The gtneral for=
TOPIC
8
3. Substitution
Alkaoes Wl<k!go oubstinrtlon leactioDs with lhr lWogen p1Il'5, dllorinr (oJ md
bromiIV (BI). in Ihf p'E'5(ocroflN light Of 011 high lempnatuRs. ~ products~
dUorinalrd and brolrl1Ntfd albnI'5. Ftt nmlrW, dllorinr rNCb with n:ces
rnnlwH' (01,) toghv nwth~1 chklrilr (01,0): Ol.(g) .. (]:(g)---> OI,O(g) .. no(&)
If m~ dl1orin~ Is
added. a mix~ of products is obtalnrd: CII,a, CII.O",
IlIlCI J • and CO,_
4. Steam reforming
Ilydrogen gas is a useful fu~l. It is made by the PIOC~~ <;If steam reforming. ThIs
procts$ we thl' natural ga:'l methane, (;II., which react:; ",1th steam undn high
prf:SS~ In the presence of a catal~IIO produ~ hydrogen and nmon monoxl~.
(;11. (t) .. 8,0 (g) - , CO (g) .. 3". 19l
~ Reactions of the alkanes
the following questions on yow own:
I. F.xpWn why albnes ~ gemn.1Jy describ«l as UIlf'tacti\~ when rom~ed to
OIM organic compounds..
2. Write balanced ChemiCa! re..ctlons fOf e~h of thO' foll<l"ing. ;md name the
~
--
'w of reaction taking pl..~:
a) cthane .. chlorine .....
b) ffit'thane .. steam .....
c) propane .. oxygen->
The alkenes
An aU,mt' bas a double (O','aknt bond brtwftn
carbon alOms. A gl1,ll1ltrd ~ Is ~
in which CD carbon itOl!l has four ~nlc
(single) bonds to other ilona, a:'I "'~ _ In
lllbn~ Alkene ~ th~orc uruaturated. 015
nch of the camon aloms invoh'nl. in thC'
Newwonls
twO
dwble bond only has th~ "ff~i~ bonds to
other atoms.
The general formula for the alk"nes is C.II",.
II,
sn.nte¢ a'l Oigallc rm"o!le
that COla IS criy single carbon
"""'"
unsaturated: . . orgaric:
rnollI<:Ue tNt contains doo..lbIe
and/or triple carbon bonds
/11
.1'""',
F''llYnl 9 The double bond in ethtlle
S t
,!
I ~ _ _ .. a.. 41\yO>...... b<:w..
149
Structural fonnulae and name of the alkenes
Earll" in this wb-topic", wr llSl'd a set of rults to n:lml' hydrocarbons -Induding
a1lLrnes.. tl~",., I final ~I'p lhould ~ addrd If th~ mol«u1~ contalns two (or
mon:') doublE' bonds:
Slrp4: If ~ are !WOOf mon:dwbit' bonds In we:atboo chain, thm Nct1 m\& be
nw.nbcn.'d ..,a<!inf: to tlw Qrtlon atom It Is attadll'd to, and llw' Iftfu:
w- (2), tn- (3) Of tma. (4) ;S indudlI'd \rtunrd.i.ltdr l:ri<n ~ -ell!' Sl.Ilfu:.
FO< ~xampw, but-I,:J..dknr
looks lila> this:
""""'"
H,C:CH,
POoplll16
H,~H-CH.,
buH-ene
H,(;;CH-C H,-CH,
-
buI-2-ene
H,G-CH=C H CH,
peot-l·_ H,C=CH-C H, CH, CH,
peot-2-_ H,G-CH---c H-CH,-CH,
hex-l-ene
H,C=CH-<><,-CH,--CH,-CH.
C,H.
.
C,H.
CH'
,
C,H.
C,H..
C.H..
"
Moll"CUlar
Branched
'\c=cH"
I
~-
C.H"
-'----------H
t>ra". one I
Chemicc
/'
~ thE' folw,..'ing rumpound: H--¢-"'~
Ii ~ ~
A=<~
H
,. Combt
St<:p 1: Tb<'t~ al~ fhT carbon atoms in 1M ~ continuous chain.
Stt'p The prmx is pmt-.
51rp 3: lbere are two double b<>nds. Th~ wffu: ls~.
Strp 4: Numbet" the <2Ibon atoms in the main chain to:sho>-· the position of
thl:' funcllonal groop_
z:
Hate that nurnboring ,"""
H fl
lclt P'J,,!tIe iI<:>t <Iouble bond
on .... boo .,om.l.r><!"
the>e numbtno ... hlghl:r
VI..,
'l1!rom
H-t-e--e
~
A i.
Name:
,hi:
pmt-I,2-di~n~
~-
Isomers of alkenes
AlLenn GlJl
h.1l,~
two t}~ of ~
• bran<-hrd i5ornl?n
• positional ~ whnl" tM d<Jubk> bond IS on a iliffrrmt carbon atom in tM
arbon chain.
150
Topic' Orp'* d>emiotry
Thf>a1~
f'nily in aiI I
fOl' uampw
C:ll, + 30,-
2. Additio
double be
1I,'t:auS(' tlw.
hrdrocarbon
doubl~
bond
- ..
--Dnw ~
-
br;andw:1 ;ondL_---"""--C.,7_----""""'----C"'' 'bu--'-.7,_--.--------
......u
_b<
First draw bul-I·.,,,,- and get the- mol<:Ul1ar formula from Ih., compound:
H
H
H Ii
);=c-¢-~-b-H
H
~
A AA
c,H.
c,", I
c.". I
c,",
c. 1
H•
C.H••
ell"
Molecular formula: C,H",
Br:uv:h<.'d OO~
"'=c--<-l-_
__
If'
,
I
H-C-H
I
H
Posilion.al i5omn::
Ii H
H H
""<'-l-e-o-l-_
I
I I t
I
II
H
H
H
H
Chemical properties of alkenes
All<enes are g<,nl'lally n',u:ti,-l'."1ltis B because the doubt" bond com break to form
slngll' bonds and add on <xh~ al<ml'<_ A1kef\es ('3n undrrgo 1M following
rNCtiom:
1. Combustion
.,
111., au.me an' highly Oammabll', 50 t~ burn
{,iSily in aif to form carbon dlo:ddt' :;md walt'r,
For ...""mple, eth('l\(' bums;t$ fuUm,os:
C,". + 30, I zeo, + 211,0
2. Addition reactions across the
double bond
_wonls
addition reaction: a ,aaetlOh in
which a small moIeculB
attachos ;ts<l'lf 10 the daut>le
carbon bond ot a second
molecule to form a saturated
molecule that contains the
atoms oIlho first rTdecule
th., alUrws are wlSiltUI<Urd
hpJrocarlJom, IMi, most importmt ....a<:tions ;Uf' addition "'Ktiom;K'W5S
doobit' bond.
Ileau~
I~
""
. ,., - ,-?-{-,
""
Figure 11 The ae"'lral equation of addition reactions across a double carbon bond.
;lllhE-
Th... type of molt'CUl" thaI
l~
being added dl>fines the tYJX" of addition ....action.
a) Hydrogenation
lIydrogo:::Dlll>on is 1M ~tIon h}-.:hogeD 10 an
aJhoIw 10 form an albIw.
all;;,..o", • II
• all;;;,_
\iydlogewtioi. is used in
irO.IsIJy 10 harden lTI:53lU'll:ed
pIa1t cis IE> make , •• gaiooe:.
"-'"
of ,,,,aet;on,1M daub\(' bond brnks,l",avlng Ihe IWO caibon atOlJlS
In 11m t)~
with only 111rct' bonds. A hydrogm alom bonds 10 each of the arbon alorru, so
thate~h has a complete set of four bonds.
~--,--,---.,.~c--~~,..,.--.-­
Wrile a balanced rea(tion uslng the stru(tural fomlula for but-I-ene to show
Wor1ted
Wrilea~
formula fQll
hydrogen
Answ"r
bow il rexts wirh hydrogen gu In the presen~ of a nkkcl catillYSI.
A=.~
~
~ ~
't
=C-C-C-H
,, ,,
•
H-H
,...
H
I
H
r
H
t
H
I
H
H
H
H
d) Halogeca
~_~_H
lIa~oatlon
alkene .. '\
b) Hydratloo
Ilyd",tton Is I"" addition of waler 10 an aim,,..
10 form an alcohoL
.
all;;("o(' .. U,O
~
. ,......,,,
><l1('ohol
New words
hydrogenation: the addiIioo. of
hydrogen to an alk_ to form
~....,
Again, in Ihis type of reaction, the double hood
breaks leaving the two carbon atoms with only
thIe(' bonds. TIle watl'! molet"Ule splils into a
hydroxyl group and a hydrogen atom. Each of
thot allao:h to 001' of thl' urualurated. carbon
atoms. so tlut rao:h carbon atom hu a complete set
hydration: the addilk>n of water
10 an alkene 10 tarm an alcohol
hydn:>halogenat: the
addition of a 1'IydI...",.. kaIide to
. . alkene to Iomt • l\aIoaIkane
Inlhist>1"",at
moll'rull"l $I>!>!
camon atoms.
Worked
Write d0"11 cI
ch\Qrine.
of four bonds.
,,) Addition I
,,
,,
AD>w~
H,
I
I
C=:C-C-H
,~
• H-o-H
HJiJ:
~ 't ~
1+-0-9-1-9-1-1
,,,
c) Hydrobalog"natioo
Hydrohalog"n'".>Oo is tM ~rlon of a lWogm halide, IIX (whne X is a, Br or
I) to an alkme 10 procluc'IO' a haJoa,~ (allryllull~).
aiken" .. JlX • haloall<.aD,..
152
Topic. Oop>i<d
;"ry
Alkene molecu
molt"rul... and
ben>m.. .atur31
is (all<'d addi!;
TIl.. slmpl('51
forms the pol~,
H,
H •
H.P=<H ••
f9n 12 EIher:
TOPIC
8
Again, tllf' doubl,' bond breaks and the remaining '-arlK>Jl atom~ are left Un5'ltUrdll'd,
nIl" h}~lrogen atom IK>Jld~ to one of the carbo",. and the halog,.n IK>Jld, to th,. <ll h,.r
"arIK>Jl, So that ,'ad] {'arlK>Jl atom hm a comp'''!'' Sl't of fom bonds,
Worked example
New words
Write a ha-lanced react ion using the structural
fmmula fO! <'tham' to show how it reacts "'ith
hydrogeo bromide (lllIr).
halogenation: the addition of a
halogen to an alkene to form a
AnswCT
polymc-r. a Ioog--chain struelure
01 <><yanic un~s that ITI"Y repeat
H"
"H
'-0
B,-H
H" ~'H
~ ~
.
throughout the structure
ad<!iti<:>n polymeri231ion: the
add~ion of alket\e$)O form one
,,
H-C~C-H
-
haIoalkaoo
"'" ,."""
H Br
d) Halogenation
Halogenation is thf' addition of a halog{'n to a" alh'"'' to foml a haloalkane.
alkrn.. + X, ) haloalkane
In this typl" of real-lion, th,' double <:allKm bond breaks and the halog,'n (diatomk
moll'lulf') splits SO that one halogen atom honds to ..aeh of the unsaturatt'<!
<,arbon atolllS. Eadl ("arbon atom then has a l-Olllpl"tl' s<1 of fOUl bonds.
.......
..
_atwater
- .to
.. '-lide
.O,Bror
-"======~-=­
Wnte down tht' balan",.. l reaction using strul1ural fWlnula for prop-I-cne and
<,hlonne.
Ans.... er
,,
,,
fI
H
~
,, ,
,,,
Ii
H
H---C-C:C
"
Cl-CI
-
Ii
It
H-C-C-C-H
H CI CI
e) Addition polyIIlerization
Alkelle molecules can be joined tog~ller by breaking the doubl(' bond in ('ach
mol<'CUI", and I~ti"g those carbon atolU~ bond with oth~r carbon atoms to
he<:ome 5'llUratl'<l. This fOrlM long chain ~lructur,,-"-, called polym('fS. The I'rOC('Ss
is call1'<l addition polymerization.
The simplest alkene that can undergo addition polrmerization is ethene. [t
forms the polymer.po[yethene. This is ho,,· many plastic products are made.
ft~
/fl
H~
/H
H~
/H
;;:c"HH
, ;;:c:,.H+H ;;==c:,.H •
Ii
l-l
-
I
f1
I
H H H H
I
I
I
I
-C~C-C-C---C~C-
IIIII1
HHHHHH
FIgure 12 Ethene can bond with other ethene units to to<m tt>e polymer, poIyethene.
S<1b.(opl< l Sa'ur.'od ond um.'urOlod hydrocaIbons
153
~ Addition reactions
Ans>-w the following questions in pain;
I. For eolCh of the following ",a(1ioll~ (I) draw
reactan" and prodlKtS, (Ii)
st~te
Activity 5
t:.arr)' oul this ell
~ro('1ual diagrams
for all tht'
the conditions for thr- I<'aetion,. and fill)
naml' all org.mk product•.
;I) ethcn and Ha
Mattria15
YOIl will net'd;
III prop-I m· ..lid Sr,
c) but .. l..,nt' r... a~,s wllh waler
d) the hydrosmatlon of pem-2-ene
2. Name th.. type of addition reaction laldng pLKf' In qllt"Stlons I. a) to c).
• 2 M lC"StlU
slol'pt'ts
• I x Ie'S! tubo:
• 2x d':,,~=1
• Scm'of
Uses of alkenes
<}'<ioh«
• l'Wtks an' ~ from 1M polymmzalion reKtion of all.:ems.. 11K' al~ ~
produced by crKlcing natural gas and CTUde oil. and aft" Ihm uH'd In thousands
of manufacturing aeth1Ii~, from plastic pacJuging and WT.lpplng to clothing
and outdoor equlpml'nl, as 'ieen In Figurt' 13 A.
• Smaller aiken.. mole<:uIM _ such as those that are formed when r>C'lrol Or
kerosene are Clad,ed _ are lB<"d a' fll!.'1 and In lamps, such as I",.affm lamps.
• AllWnes a,,~ al:;o lJ$('tJ as raw mat....rials for Ihe manufacture of industrial
cheminls. 'lUCh a.s akohob (ml"lhylate<1lpirits) and alckhydM (for paints, I~m
and ~). both of "'hkh we will kilm about in till' neJlI f~ 'iU~topi<'s.
• 1bt'y nn aho boo: ~ to promote 1M iUtifidal ripming of fruits. As a froit
ripl'llS natuRll)", il gh-e off:l t~ ilmOUJIl of l"Ihl'ne. whkh moourilgl'S OIhrr
fruit (on trw- s:lIJ>l' trl'\" 01' in thl' Silml' stOl':lgl' containrrJ to ripm as Wl'1I. l1X"
u~ of l'th('l\l' to ripl'n fruit Ine:o.IU tlat mOl'\" conlrol nIl bl' had O"'ff thl' tim..
and uniformi!}' of the' rlpl'ning.
!B
~
;\ , Experi
>,"~"t"~ii,"'''~".-"",
-;0-;
13 Some uses of alkenes:
• Scm'of
• bromitx" ..
•
ObKrvatioIU
Now any chana
from Ihl" rtlOCIlI
addl'd. !(e('p till
few minutes, .aD
Conclusion
1hl' unsatun:m
qukkl)" "ith tbI
(from brown to
hydrocarbon rei
brUJIlhw and de
(Ih~ Is no cokJ
is llOtkNble am
P' tics W. paints (B) and the ,ipel';''!iI of fruit (C)
Activity 6
Saturated versus unsaturated hydrocarbons
1hl' unsalurated h~'l1rocarbon is much mort' reaeth'l' than the satutated
hyurocarbon, U lhe uouble cartxm bonu bwaks eUll)". Il'aving space lor oth...
atoms 10 bond 10 thto hydrocartxm.
A :Illturatl'd hydrocarbon ami its con~ponuing unsaturate<! hyunk·arbon
cannot e:l$ily be dhtlnguishl'd by comparing thel. physical properties. A chemical
test must be conducted 10 see if an unkr\o'ATl hymunrbon is saturated O' noI.
154
Topic' Or:poi< eliot • ,
Two unlabl'llrd to
contain cit...... C)
I. Whkhmmp
3. Onr of til.. cc
the l",m.., of
4. Explain ho,,·
.....maiIueitb
.....
.
I!!I!m!EII Test for saturation
QIlTy OUt Ibis upmmmt
1 Experiment
Matftials
You Irill na"d:
• 2 ~ test rubes 1\ith
SlOppt'n
• 1 ~ test tube rack
• 2
r,;::':;:':.,
"ng
In groups of fOUL
~
droppers
• 5cn,'of
cydohexene
• S em l of cydobcxane
• bromi.... water
(IOdropsl
• I x "",!1:tr <X 'Itid.:el-
: Aim
Tn use bromlnl' watl"l to tkterm;nto if a h)"t1ro<:arbon is
S3luratoo or uns.1tur.llted
Prt>C't':d.u",
I. PIau" S I'm' of lycloh~xane in one Irs! lUbe and
5 em' of ~lohexen<:, in lhe other. I~l eiKh. of
the 101 lubes with tht' markeT Or stld:"'_
2. l'IalT fiw drops of bromine Wiltl'\' in tach of the
test tu~ Add a stopper ilfld mix by.ru.k.ing W
test tubl!.
3. 0b5<0n~ ,,'1m h.lppnts and reronl your ob5orr\.,.tiom.
ObsotrvatiOIU
l'ott my changfos in roklur In "too t~t IUIx'
from Ih.. mommt trno brom;n(' water Is
added. K....-p monitoring ooth test tubes for a
ft'W minul<!S, and ch('Ck again in all hour.
'11\('
unsaturated hydronrbon will react
(jukU)' 1\"11 till" bromine and dKOlour1Zf' II
(from brown to cWu). whll~ Ihe l.1lutalC'd
hydrOC<lrl>on reacts '''r'f}' slowly with ItHo
brom~
and d«okJurIsn ntmn~ly slowly
(IOO\' is 0(1 rokJur chan~ 1mmNi;o1~ly. bul il
is ~e M1ft SdJ)(' tlrM).
---
·~is~
keep it away
lIai,.,1aDle
•
~ is higlIy toxic ~
tIhaied. inQes1ad or comes
rno oontaet .... th the ski1.
F'roIonQed $100 contact can
cause bIms. Wa:sh witI1 cloon
runring _
if lhe bo..........
~ ycu' skin. S<Dety
9OP' a'ld~gIo¥es
musI be..em. The expeoil'''11
"""*l be p6b,,0I!Id"3 bne
(:IV·.d.
I!!I!m!EII saturated vs unsaturated hydrocarbons
Two unlahclkd bottles art' foulld in a laboratory SIOrenXlTll. It Is known Ihal thl'Y
rontain ('!th", Cit. or C,lllO" Allswer the followIng qo<·,tions on yoor own,
1. Whkh <:<lmpound Is saturated?
2. Name both compoonds.
3. on... of Ihe ("ompounds has an isom",. O,aw the suuctural foromla and nam...
tIM! isomer of th~ rompuund.
;J. t:XpLain how yuu rouJd use .. broml~ solution to detmnlM which hottl('
ronl;;ul\S eilhft compound.
SUB-TOPIC 2
Homologous series
Physica'
Organic compounds are divided illlO separate familil"S or grool's aITOrding to th('ir
physical amI <'hemical properties. l1te family an organic compound bt'1()n~ to h
oocrmined by Ille functional group in the organic molKule.lbis is any atom, group
of atoms or bond Ihal repla«>s 0Ilt' or moT\.' hydrogen atoms Olllhe carbon chain.
F;.l('h group of compounds With ilS unique functional group f<>rms a 'family'.
known as a homologous series.
TIw lahl(' below summarizes the homologous series that we will study in Grade 12.
alkanes
,,
-c-c,,
alkenes
'/c==c,.'
alcohols
carboxylic acids
,
,
-C-O-H
0
""
/ 'O-H
C.H"",
name ends in-ane
C.H",
name ends in -ene
C.H,~,OH
name ends in .()I
C.H,.O,
name ends in -oic
oc"
We will also learn about the organic compounds, the est<'IS (see Noll' un llage 1&4).
General characteristics
New words
luJlCtional group: a particular
• Each hom"l"gou.~ serie:; ha~ ifS own w,i,!u"
bond, atom or group 01 atoms
general formula and naming convention, a~
thaI is responsible for the
we have seen with the alkancs and alkene, in
parbcular prope<ties lrl that
the previous sub.'opic.
group 01 compounds
homologous series: a fami~ of
• Successive memb<'rs of th" series bc<"<,me
organic
compounds that share
larger and h ..av;"'r as a carbon alom is added
a particutar funclional group
each time.
aJcohols: a homologous series
• The ph~ical prop<'rti.,.;, ,uch as melting and
of comPOUot!s that contain an
boiling points, and d'm~ity and 'OOlubility,
-oH fu"lCtional group
carboxylic acids; a
change as the molecules in a homolo!':ou,
t>omok>gous series of Wilak
Sl.'ric:; become larger.
organic acids that confain a
• The member~ of a homologOU5 Sl.'ric:; have
-COOH funclional group
similar chemical prOp<"rtic:;. This mean, that
th\'}' will undergo similar t)-pc$ of chemical reactions with other substances.
• The distinctive feature of all the members in a homologous series is that eadt
member differs from the pl'CVious one by only one -Cll.- group.
The strnttul
compound
strncture, II:
As th"!IlI
molecular n
• the densz,
• the boilil1
• the solub
are not'll:
The tables b
melting par
methane
ethane
propane
b""~
pootane
b~
"NMc:Tb.",.
the propaI><' III
point, bUI ,"'"
Answer the
1. l>eftne 1
a) func
2. Write do
a) C,H,
3. Comidl
a) Ho...-
b) '1'0"'-
8
TOPIC
Physical properties of homologous series
_."
d,,"
group
molc<-Lllar mass increase5. As the mole<:Ular mass increaws:
-.y.
(.Orad",
The structu .... of an organic compound influ<'nn:s th(' ph~ical prop<:rtif's of th"
compound. Sin<'e lhe molecules within a homologous wries have a similar
structure, tht'}' have similar physi('al properties.
As the mole<Ule increases in ('haio 1•.ongth hy the addition of a -CH,_ group. its
•
12.
.n-ane
th~
density increases
• the boiling and melting points increasoc
• the w!ubility of the alkanes in organic solvents decreases. (Not...: The alkan<'S
are not soluble in waler.)
The tables b<clow illustrate how in the alkane homologous wries, the boiling and
melting points, and d('ru;i1y increast' as th(' carbon chain gel:llonger:
'!'!IN Alkane iiIf"! ,,".' . Formula,.. ISOillng P9int ("ej Meltirig pOtnt ("Cl
-161
-182
CH.
-~
....5
183
C,H,
I
_n-ene
...:::",-1
. . . -oic
1M).
•
--
""""'"
1
""""~
C.H.
-4'
-188"
C.H",
-<).5
~1'"
pentane
C,H"
C.H..
"
~95
""'~
""=,
.
"
"'"
"N... ~, n", "",llmll pom' 011""\"''''' " h'Rhe. Ih,,, ,h.. of bu.. ne. Th" .,
be""",,, <>f 'bo ,b.p< 01
,b. p10l»'" "",\(><.. 1" Mol"",l.. 'hot CO" ~I< " .. t1y
cry;tal I"'~ will h.". 0 Jo.....- "",lIh\/:
but 'IKM with odd ,hope; (ti.. ,h.. of p1""''''') ,,,,,d '0 hove >Iigblly highcr "",Iting poin".
poi"'.
'"to.
• knilyol
'~ser>es
-'
:.-~
-
-"
-,
~.
_each
~ Recognising homologous series
Amwcr the following quesliorn On your own:
t. Ilcfu,e the following:
a) functional group
b) homologous xri~
2. Write down the name and the g.meral formula for th~ homologous series of:
a) C,H l l
b) C,Il.
c) C,H,OH
d) C,H.o,
3. Consider the organic compound, butanol.
a) Uow many carbon atoms does butanol contain?
b) To which homologous series does It belong?
Sub_<opK 2 Homolog....., ""ios
157
SUB-TOPIC 3
Alcohols (alkanols)
--------Organic alrohols (or aJkanols) are a homQlogous
st'f'iol"$ that a~ chara<'terized b)'the functional
group .oil.
Of aU th\" orpnje alcohols, Iht mOlO!
lmponant is Mh.anol. Ethanol is I'rodun'd wlwn
Isomeri
Alcohol isc
• branfhir
• mo\"ing
numbt'n
fruit, wgttabk-s or grains are fenntnll"d. For
('xamplf', 1M uaditlonal alcoholic ~'ffagn
such as kaulla, are 1TIiI~ from ftormented grains.
FIgUre 14 All over Africa, mlIIet is
f..
to make trnditional beer.
,."",ted
Chemical composition of alcohols
Much lite Ihl' alunes and
alkenes, akohol.s QfI undergo
Gllf'lLOllKm 10 IlUU 1M carbon
clu..in ~. ~ c:hm1ka1
propf11i<'S mnaln similar as 1m,
duJn grows, but the physlnl
pmprnk's diff",
,
,
-C-O-H
>HlH
entsacaboi,
et..-. of any Ier'lJlh)
(Rlepi
Names and structures of alcohols
Tho:' nmling of alrobols is slmllar to uu, naming of a1l:an<"s. The diff~ is Ih.u
thor ~ al the md of IIlC' albm' nmK' Is ft"Jl~ by -d fo< 1M akohol.. Ag;t.in, t1>(Ion,vst chain Is numbr1Td so thOlt 1M carbon alom tlon<l«Ilo tM -OH-group is
the loowfost nu~ nrbun.
-
~am(' 1m- folloo.1ng ako"ho;:;',,-----------------H H H H
-~-H-<>-"
~ ~ H H
l. There are four <'<llboll51n longest cham: but-
Z. Therf are only slnglt' bonds in t~ carbon main: -fin
3. nt,e is one alcohol gUlUp:-uI
4. ~ carboll atoms m<Ut be numlxud from tht' right to ge1 the lowl'St
nu'nbe, fOl the -011 groul).
Nam..: bulan.I-o\
AnSWff
tbe
I. l>n"'l
a) ~h.;
2. I)rawa
a) 00:;
3. l)raw ~
Fonnati
Akohoba
• h)'dr;lltiol
• hydrolys
• ft'rmt'rltil
I'l.'Tffit'rl tati<
11lt' lim
matt'riall it.
and Iht' mt
CQmpl{'l('.
~
. TOPIC
-
8
Isomerism in alcohols
Akohol ;s0rnn3 all form by:
• branching lilt' rompound or
• moving lhl' -OIl groul' to a dlffcft'"nlnumb<:'n:d C<lJbon iltom in the' longc':U chain.
Remember
_Il'deo-
Compounds _ isomeo s if It>ey
hIMllhe
IcnnuIa, buts dil'leo.,l
-=-------,,---~For butan-I-(>l, dr.Iw .. 00
na~
I. a brancll<'d isomE'r
2. a pooosition.J.l 00IIll'L
-Hi+
H
H
AJn"Wtr
2. I'ositiolW bomn':
I. Branchf'd isomer:
~
"
"
0
~-H Z-llll'thyl-prop.m-I-oI
,
bulan-2-ol
A I A
"~-
~ Isomers of alcohols
""_>15 that
win, the
f-goup Is
Answ,', the following rluestlom on your own:
1. Oraw the
~trn(\urall()rmulafor:
al '?thanol
bl pmpanol
c) butan-l-ol
2. Draw a structwal formula for the position,,1 15Omt>. of:
a) butan-I-ol
bl pl'lltan-I-ol.
3. Unw a brillKhf'd iiOmcr for JX''ntan-l-01.
III
pt·ntan-I-ol.
Fonnation of alcohols
AkohoIs em
~
mack' by:
• hydntion at allrzne (this Is ~~ in Sub-topic I Wlder W rnnlan of .. I~)
• h)"dro/y5is of est~ (thb will hi' dl'iCUSW'd in SuD-loptc~)
• fermmtation.
Fl.'nnentation unly applle 10 f1hanol. No other aIrobol. can br mad!' In Ihls ....y.
~ first stl1l il. to brl'U the' rompk'x al'bohydl1ltes {from an)' suochy pb.nl
lIU.1~1) into simpkt ones by l1C'ali~ thf, starch in bot W3ttt. Y~ast b Ihen;K\dl>d
iond thE' mixtuR' ~ kqlt \Qrm for up to Sof'\'ff.ill cbys Wltil tM f~titton 1$
rompk>t~. Air is ~ out of 1M mhrlun" to pn"''ffit th~ oxkbtlon of till' nhionol
ColI"O~ (s..g....,
=,
2(':",0" (~thanol, 0 2<:0, (.....rooD dioxid..)
_..."..,.J Akohob (O'boob.)
159
3.
Chemical properties of alcohols
Al«.>hob arr I('Ialiwly ~aetive and enily
underlo thr following rractions:
Did you know?
1. Combustion
re'! 11 e d wI'-.n etI'W'lOl
Akohols, such as rthanol. and rnrthanoI, an'
mrd n fucls by makin& usr of C'OIIlbusIkm. 1br
alcohol bums in the prrsrncr of oX)'Kffi to
prod~ ollbon dioxidr and ....aler. 11K' rraC1ion
is rxothl'rmK, so it rele;Ut$ heat. In this
l'xample,ethanol underg<.>cs combustion:
AlIt1ol.9' c.bon r!qcOde IS
Ulldeogoes oombu:stIon, elhanoI
~ cooiSKiered a muctH:le ....
tu.l than 1OSIiIluels, such as
peIn:ll or diesel Tttis is beo=;a,_
the et!l8rloI coones from a
f~ reso::ur:e - plants.
When plants ate cultiVated to
make fuel, ..... call it bdueI.
(;,11,011 .. 3U, ,2(;0," 3U,U
Ethanol i~ uS('(! as a petIOI substitut(" In
oountries Ihat are 10"" In oil resen~ but high in
crops that can be u'l'd to plodu~ ethanol (s~h
itS wgar cane or malzr).
2. Dehydration
An al«.>hol undl'fXO"S dehydration in thf
presencl' of a C"ualysl and heat to fonn iln ,llktne and ..-at= 11lt' tNC"t1on rrmm'l"
the -Oil IfOUP hom thr carbon atom and ,I h)"drOgffi atom from an adlxmt
carbon atom in thr sa~ mok<:u~. A double bond fon= bl'tnfell t~ two
arbon atoms:
alcohol
._. H,""._ H,PO.
--Ethanol undetgon a
phosphoric acid.
Alcohols c
oxygen ate
",ill be OU
thrfr~
7'
,
.,
"-O-C~
.:lhanol ca
an oxidizil
l"".,nanga.
4. Ester
F,steIificat
feafts "itb
and wale<.
catalyst is,
gently.1hi
Uses Oi
• Th<=
• ~"""
Ml'thzn
•
>alklMlr .. ",0
The roll' of the add nl<>lyst is to donate,l hydrogen ion 10 th(o, 011 group of the
alcohol, and thm aC"O"Jlt a h)"drogl'n ion from another part of !he <>Icohol. This aU
happens at the samr IImr, so the acid dor:s not appear to tab part in thr rraetion.
Such a cat<>lysl Is called a dehydrating catalyst.
U~
d"L"_yC"'C.C'C'o-n-~C.-~C'CoCnC;Cnc,C"C.-pc,C~CC-~-of7oo-n-,rn-,-,,-,-"'-C--structural formulas to show how the chemlal reaction
~
Oxi~
•
"""""
"""""
"""'~
s",-ab-.a
•
""".."~
is al"" u
Answer tho
I. F.xplai
2. I:>ra,,'
3. Write
4. Wri:r,
a)
S~
p:.:
"'=
Gh~~
6. Statr:
,~
160
Topi<IOq;anl<'-i<tJy
""'"
TOPIC
8
3. Oxidation
Alrohols can undergo oddatlon reaction.. Oxidation Mel'S to Ihf addition of an
oxygen atom to ttHo alrohollo form an add. If l"thanol is Iffl sl,lndlng in air, If
,,-illbE' oxidiHd (,,~th fhl' h('lp of N(1('ri", 10 fonn l'thanoir acid (VintgarJ. 1b.is is
thl' ~ason "'h)' wine goes $OI,Ir if it is IMr oIJ"fl for wme Iimt'.
" " ..!!....
~-H
II
HH
Did you krurtl?
"
H-J-i'
1'---
The ""'lfd, W>llgIf.
IIU-H
"3CU w.ne".
f..ttwlol. can Ilf' oxidizN much faSlf'f by adding
an
comes !rom
an old Fnlnch tel'm 1tIat ~
oxidizinJ: agmt. such ~ potassium
prrmangan;ltf',
and thm ...... nnlng the' mixlUR'.
• ... wonl
4. Esterification
esteo j;icatioq; • e:atliIyz.ed
reaction n which an IIIcohol
reacts with • c:artloxyk acid In
Esterification is a rt'action in which an alcohol
ructs with a nrl>oxylic add to form an <'$ter
and water, in I~ p'r5l'n«> of a "atalyst. llw
form an ester and
w.rter
catalyst is concnltrat('d sulphu ..... add. Th... ,....dlnn mlxtllr<' must bE' heated
Kt"lltly. Th.is I"action will be discussed in mort' dMaH in SuIHopie S.
Uses of alcohols
• The smaller alcohol mol.....ules are mainly
u~
a'
~ln·nls.
Ethanol is the major
mmI'on ...n! of methylate<.! spirits.
• Mcthanoll~ u,,-od as II pl'UoJ addillve 10 improvp ,·ombustlull.
• Ethanol is u=i In the ,",xlra("tion of l'S:;\,IlCl.' from fmits and spk<.'S, u a
d4pc=m for d)"es in !a<"<IU"rs, and;ls" solvent for fragranpl'S in perfurtles.
• Ethanol i. found in alcoholic beverages. I! h used "" an antiseptk in akohol
swalx to di';nfen Ihl' s.kin bl'f01'(' an injection. for example.
• I'ropan_2-01 4" w1\<f'nl in ink-jf't prim('1" ink, cmmrti~ and lood fla\'ourams. II
i. also mrd In d ..aning fluidS for Hems SU("h;lS compact discs.
~AJcohOIS
An...."" u,.. following!:'-:,:_::::"":::O,C=-=.::::-"":.---------------.
in
Explain "..hy lIlrohols III re~ in " ';mil:u w:a)".
I","... U,.. mucrural formub for 1M fun<:tionaI group at akohoIs.
Wril.. dawn tM gmf'Tal formuLa for Ikuhoh.
Writ.. 1M moIrn>IU fonnula 100 dn... thl.> WU<:tt1I1l fonnuJu for.
I) pt"0JI"fl-1 ~
b) Ult'ttw>ol.
S. Suggnt;l w:ay 10 10m t1h1no1 imo <"thaIH'. and Ihnt bM:k 10 <"thanol:apin_
Gi'T rqualkms for I~ I'l'Kliol'lS ;lnd l\llfII.. Ih"l}l'" of ...lI('tion in tlC"h~_
6. 51"1" Ihrtt mn of alcohols.
7. Dncn"lr u... krment;l.liull pro<:tSS.
1.
2.
3.
4.
SUB-TOPIC 4
Carboxylic acids (alkanoic acids)
~ eatboxylk acids ar~ a homologous series of "''i!31.: organic acids, so the')' have a
sour IMtl' lind can tum blu(' litmus papt'r red.
•
butanoic a
I~
Chemic
_.
an\)oxylK
FlgtR 15 EthanoOc acid is
responsible lor the sotK faSte of
Formation of carboxylic acids
Carboxylil' Kids out' made by the oxidation 01
akohob. as " ... saw in Sub-lopic 3. Bul lhl")' can
also b<.> madr by the hydrolysis of !'SIN'S. This
reaction If'llU]'('S a dilute acid catalyst and heal
to OCCUI:
reaction, •
carl)ox,-1l
f.Jlampil
New_
carbox~1
F.xamplo
hydrolysis: a deoomposltion
reaction due to the addilioo 01
rarl><.x,-l
wat...
fxampl<
mr.. + ",0 OK ~'''. ~';I.rbo"'yli<;";Kid • alCOhol
Uses a
Names and structures of carboxyfic acids
• fJtwwi
•
Naming Ihe nfboxynr adds is sUnllatlO IhI- alkanes, but ttk"., at th.. ffld of thl"
aibm' nam(' Is changed to -oil" ariJ. The functional group is a["'ays on th(' first
carbon alum ]n tll.- chain and so tlu' numher I, omittoo lrom the name.
•
••
TIw tabl.. shows the n3m" and ,lructurfS of the first 6"" carboxylic adds.
"""" .
",.~
Mt'tha.. .
bru~hln;
•
•
BUlan'"
Cllrlc '"'
,
methanoic acid
,,
P
C
H-9, '0-,
CH,COOO
2
Am"'.... :h
10 I>u.....
• ) p«
2. Wrilt'
a) t'lt
to) hu,
l. L)(oscri
_.
1CiiIS)
Name
propar.oic add
C,H,COOH
,
C,H,COOH
,
C,H,COOH
,
Sttuetural formula
H"
I
I
0
Formula,
Chain length
17
H-C-9- C
~ H
~+-C-'
butanoic acid
'0-"
", ", ",
, ,
"""
P
H-C-C-\-C
pootarlOic acid
'0-"
-c'P
'0--11
...
--
Chemical properties of carboxylic acids
Carboxylic acids aI<' weak adds anll thus react likt' typical weak adds_ Th('S('
rea<1ions indude:
. . QSteof
<":arboxylic add .. bare --'> salt :and water
Example, CIl,(XX)Jl .. !'.:aOB
carboxylic add .. carbonat.,
..
---'>
NaCH,COO .. 11,0
>-.alt .. water
~
(Carbon dioxidc
Exampl..: 201,COOII .. Colen, ---> (CH,C(X)),Ca .. ",0" CO,
~'arboxllic acid
.. metal > salt .. h}"drogcn 8'u
Example: 2CH,C()O!l .. Mg --> "'lg{CII,COO)," H"
Uses of carboxylic acids
'JI th~
'm
• Eth.1noic add is ust"d as a preS<",vative and food flavouring.
• ACftk add i., U$M as l'DaJ.,'l1lam in Ill" manufactun' of roblx'r. It is also U5Cd in
the manufactur~ of various dyes, perfwnes and rayon.
• Mcthanok add i~ an add found in ant venom and some plants, su~h as lh~
hrushing ncttk. whkh ~tings you if you toudl it.
• Butanoic add smells very had. It was first isolate<! from ran~id buner.
• Citric add (a ~omplex ~arhoxylk add) is found in ~ltrus fruit.
~ Carboxylic acids
Answer th.. following 'Iuestions on your own:
I. Draw strunural formula.. for 0,.. following carboxy1i~ acids:
a) propanoic acid
b) hutanoic acid
c) \'\hanoic acid.
2. Write ha.lan,·ed ch.-mical r..a,tiollS fur the fulluwing:
a) ethanoic add + zinc
b) propanoic acid + magn~sjum ~arhollat ..
c) hutanoic acid + cakium hydroxid...
3. !)e,;crihc two methuds to rna!:.t' ~arboxylic acids.
S"b."'plc 4 Carboxylic acid> (i1l;;Jnoi<
.d~,)
163
SUB-TOPIC 5
F.stl'f'I all' a
Esters (alkanoates)
group of organic rumpoundi
Names a
lhill art widely found in ~tUIl'. 1lu'
slmpk est~ lend 10 tu''f' p~asant odouJ'1. MUlufacru,..n of food and
ottl'n;tdd esttn to milan« tho!' tlan,,\Ir or odour of th<' food or drinl.
~~
name 01
add
I~t ""t'I
ch.angl'd
:0 tI
.suffu: is dl'riI
TIM' table I
, DIll you know?
we say 1haI es!:/lI$1(lIm •
Th~
IlItI'4'
CJfOlga"'~flIlher
than saying !hat lhey form a
homo "og:M '$ seoes, ThIs is
be<;a! ISe estets are not strictly a
homoIo9ous series, The
lurdionalgroup in EllIteiS
OOtlSists of the uniquely
identif.able -COO group, bul OIl
either side oIlhis part are two
carbon cl1ains Ihal cao'I be of
anv length (ard are lhereIore not
triQue to Ihe luooctiOloal ~
E31l'n are produ~"t"d b}' eslerifi~'ation ll';I('lions,
a~ we saw in Sub.topio: J. In this l}"pt' of
rraniun, an akoh<.>l rea<:u with a G1rooX}'llc
acid lu fOnII an !"Ster and ",11~ in Itw ~1'K"t'
of a ntal)"St. whik' the rt'artion mL'Our(' is
gmlly hNted. The' Olta!y$l: tl; «XI.~ntr;l1td sulphurk" add.
Thr- ~ f'<I~lion for an rsttrifl(Ollion rtiK1k>n is:
al.... hol .. c.rbox)'lic acid'- ."'., est...... ",0
ntis em IX" ~It'd ming formuln as follows:
n-o---:;,;'··;···;;.:.:o;..c'? ......
_., R-o-<:.~O
, ...•.....••..•
"A'
• H-Q-H
'R'
The
nam~
.._
nameaIll"Stl'
Skpl: Thf'f
""""
O~1P
fu~
mise
Sh'p 2: Th('.
""'"
,-
""""
""""
Step 3: 1br.
Th<~'"
Worlced
F'!Iure 17 The geoeraI equation of an
esterification reacTion using formulas
Name the fl:
TI'e alcoholloSf's a hrdrogl'Il atom and the
carhoxylic add 1,l5l's its .(111 group. TIlt'
hydrogen and -011 group Ihe" bon<.! to fornl
W3.tt'f. TIlt' alrohol and Ih~ carboxylic add
('ach now
,m 'open' bon<.!, so they bortd
with t'ach oth" to form Iht' f'Ste'l. Catenal;ort
ocror.; and th~ l5tN dlain ~ in "'ngth.
Answ,,-r
St." J
hi"",,
(~
lealom ...
\mel/l-) _
Fruitsandno.. ers
and c:ornpIex
ntRfS. The partkl.IIar~
of esters gives eadt fruit or flower
Its characteristic $WMt srneI.
~'SIure16
~ many ~
Step 2 (add
Step 3 (.lkol
Namr. llle'tt
TOPIC
8
Names and structures of esters
Thl' nam" of thl' "SIft is dm~~ frum the namC'S ofth.. akol\c)l and lht carboxylic
acid thaI "."... U5I"d to m~ thl' ~1'1'. Thl' part ok>ri\W from thl' a!roool is
changrd \0 u.., flMM of Ihe rorrt'SpOIlding all<yl group:.oI is ~LKed I'oith _~~. The
~ is derh"nl. from lilt> aotbox)lIc Kld:« <>rid is ~ by~.
Th.. ubk ....k>w $ho'.o'S $OtnI' e:umpks of esters :md h.- I~· "\'f'f' l\lI~
ethanol
!T'lEIltllW'ooi acid
ed'Iyl rnetharaoate
butan--l-01
pentan-l-ol
ettwIOie acid
butyl
~acid
pa""lt)1p1op81_
echanoate;;;;"-==:::l
Ie
Thl' ruuIlE' ~ abo .... WOlkt'li OUI fnxn th" stIuctun. USC" 1M foUowing steps 10
Dame ;to ester, gl\"tn iu SIn.N:tul'f':.
Stl'pl: lbe ntrr \$ di~
bM~lh"eubonand
oxygl'fl In thl.' l'Ster
fuoctional group. Mul;;
Ihis division polm.
F'9\lre 18 Tl1f: two parts of an estcr moIe<:uIe:
SIl'P 2: TIll' acid part comains
acid
and alcohol
the ""honyl group
(double bond oltygt>nj.
Count the num.... ! lIf ("arbon atoms in the chain, and uS\' the suffix, ....... fr.
Step 3: 1111' akohnlls dt'rlwd from lhl' part with the oxygt'n atom In th" cha'n.
Count the numll<'r of carbon atoms In the chain, and uw the suffix, ·,.1.
The naffilO of the compound In Figure 1& is rlhyl bulanoat".
-'-----------Nam.. thr foUowing t$l.rr:
~leIP 1 (aod pa<1J:
3(; _
.. "haot1
Step 3 ~ partl·
1 (; al"'" In ",,->
lmeth-) ..... " . .1b
Step 2 (acid p:.tnt.
( p i _ I .....
:~-
\'¥lIh l c:lrbon a1oms, this add " ......Id be propaDQic
Kid. Tlwo~~ pr<>panoote
Step 3 (ilkohol part):
WIth I carbon atom, this alcoh<Jl would be m~b ..noL
Therefo~ met h}'l.
NiImr: methr1 propilfl<)llle
Forl'xampk
Chemical properties and uses of esters
1. Esters undergo hydrolysis to make soaps
The In'C'l$I" n'ac1ion of esterilintion is hy'drolysk. As ~ Ie~mt in Sub-topic 4,
hydrol)'SU is ~ Tt"Ktion with watl:!' in which the 't'ac1ing rompound dt'rompost'S.
In tlUs case, the estC't: df'('Om~ intO ~ n.rboxylk" ~cid aod an alcohol whm it
rNcts wilh walrr in the pr~n('(' of a weak add.
R-O-C~.'
H-O-H
~
R-Q-H
•
..ompounds
..an be rl'pfC
1a$It" and $:I
p"""'.
"-o-c~.
F'ogwu 19 Hydrotysi:s is the reverse maction of esterifW::ation
'Tho arT"QW in this equation shows that the reaction is AlYersible.
lIo....'··. .er, when an ester unuetg<l('S hyurolysis In
the pTt"Sen<T of ~ b3se, Ihr pro<TSJ is known as
Ilaponificatioo. ~nd the produn is SOl.p.
Traditkm.ally. olnimal or ~-ege1~ble fats "'l'T\"
boilw. up with <Uh to make- SNp. Toda>', the
Ilro..~ Is mOrC rmned, but til.. ('hemlstry stays
tho' same. The \'t'gl'tabk' rat that is uwd today is
an ~ter <JI g!)'t'nOl, md aq~s sodium
hydroxide (a Wl:le) is USC"d inste~u of ash.
C':'Ier of glY"CI'ol + aq"eou~ NaOIi
> gly.... rol
New words
saponific,ation a
deeam...... lio<o ,etdioo,."". to
the additioo 01 water
biodiesel: a diesel replacement
thai is made tn:m vegetable or
a., B-1 eel oits that <:Olltai", a
type 01 ester
cenan
+ 1>Odium salt (,roap)
F"9Jre20 A
l\aVoUr and ,
syntheticall
Answer the
1. Ethyl til
~lcohol
....
the.
2. Esters undergo combustion for use as fuels
II)
In Sub-topic 3, ,,'I' .....w how etlu.ooI. all' be used:u:Ii bIotuet (as a pe1IOI substltute).
FSIl'n, h~.."., as.. ~ 10 a differrnt t)'p('of b\oful bk>die;el. Onl)' ~ters thai
haW' a long carbon ..hail' on 0"':' sldl>, and either a meth>1, ethyl or propyl group
attached 10 Ih<.' olh..... side of Ihe est<.'r fUlll"tional gro"ll ..an be used in this ....ay.
Vt'g<.'t3ble and ~nirtUl fat-ba.sed oils rootain ~t<.'rs, but th~ al'\" ~ ~lWays the
romct t)-pe of estff. ihrrrlon", lho' oils haV\" to undergo a PhXriS nIlw.
~(icationbefore tho' ~ ~ of estft" Is produad.
Whl'f\ u'it'd in ~ di~l engine, biodiescl rombuslS to fOffil carbon dloxid... and
waler _ pnxluCls lhat (despil'" the gre<.'nhouSl." ga~, <"arbon dioxld<.') ar<.' SI ill more
elwironmCnlally flkndly than Ih<.' prodU<1s formed whell pe1toleum·based diesel
Is usn!. In th<: e.un<ple below. methyl olNtt" is t~ biodiesel:
b) thl"
C:.." ..o. + 270, .19'4::0, + 18",0
3. Esters have pleasant odours
Although natural food aromas contain rombin~tions of organi( (om pounds,
including 1"111'11, syntbE1k I"Itt"t'S ~rE' added to man)" foods md drink>; to make
them tut .. simi;"r to tht" I'\".t.l fl,woorant.
..) the I
d) tht'"
2. FSlers a
II) ~
b) Wntl
.....
~>~
c) l"am
d) \\'h:a!
3. Named
For ...xampl.... the natur~ aroma of bananas come fro:n a 00"_ _0:
compounds, but tb... dominant fI,,'-our is that of ~ pa."ticu1a - . ...... ..can I:ll" reprodu«d in a laboratory, and oitddl'd to foods md clrI:1b to 1DIiIR ......
last... and IDIl"U mo... lil:t a banana -~<'fI jf Ih... full spl"Ctrom of fb,'OW IS.-
1""'"'.
:
,
em.. «
~'9UA! 20 A real banana .... up to 50 diflerent organic c;ompounds that make up its
ftavotK and smell; Banana·t\aVoured if;e etearn rare/y cont<'tins real banana. so the
syntheticaIly-pmdueed banana lIavouring ester is addad iMIead.
ICmlllIIII Est.",
Answer th" fOIlOWl~·ng:=qC~:::C.,C.,C"C,C,C"C)C.~::C,CoCw::C"C, - - - - - - - - - - - - - I. Ethyl bulannate is an organic compound fnnn<."d in the real'lion between an
akohol and a carl)(lxylir acid. Writ... down the {"Unwinl;:
a) til.. nam.. of tilt' family of organic compounds to which ('thy] butanoat ...
belongs
b) Ill.. nrnMural formula of the fuonional group of lilt' f1lrooxylir add
c) the name of Ihe acid from whkh <."thy! butanoate is made
d) Ihe slnK1ura] formula of ethyl butan();lIC.
2. J'..o;I= ("an I:ll" p.t'pllr~ in th... labor;uory.
;0) Namr on.. USf' of fStefS in t~ food indUSlry_
h) \'1rile down the balanced re<>etlan (using strummol (ormulu) that shows
how an esler is produ«d using 10 drops of et:ha.noI.... add. 10 drops of
I'Ihanol and ~ drop of ron..-mtralOO suiphurk add.
....) Na.rtH' 1M $t'!" l!'Ial is formed.
d) 'Whal is 1M purpost' of the sulphurtl'" arid i:rt 1M .e~?
3. NzJIl(' Ihr following fSttr:
H H
"
~e--b-H
~cT
.,
""
"I
_1Opl< S toIcn talbDootol
167
SUB-TOPIC 6
Macromolecules (polymers)
In Sub-lopK I, ~ SOlW hoW aIk~ GIn unlkrgo
;oddition poI.ymftiUtion 10 form p<>lymt-rs (kln,g
--
Polyethe
TIlt slmpl.e
polymtr. p
•
><
chain structure). In Ibn $l.Il>-topk, ..~ ..ill
inw:sti~t~ this bnnch of ~ dH:'mistry and
:lppre<.U.t~ how much ..'" rt'ty on plauk$ in
modern lif~.
Mutics <lIl' mack> from \~ large ~ntbetic
polymer molKules. In poI.)'IIH'r scienCl', we UW'
the tfOrm, macromolt<:nl/!. 10 dl'!Kribl' a Iarg('
molecul.. that consists vi a number of repeating
PolypfOl:
uuiU. To dislingulS]1 between the lwO, we wHl
Figure 21 Pl""tie prodU<;ts ara
the term macromolecule to deS<"ribt' a sillj;lt' part of om everyday lifo.
molecule, and the term polymer to descrlll<' the
material (pla"k) thaI is made wilh those molecules.
US('
Proptnt::a
l'olyl'ropnmlghl d<.'gt
laboratoryj
Macromolecules form when many small molecules join together to form a
structun> that TE'peats iuelf ~r and ovu. The small rt'pt'ating units art' nlled
monomn:<.
............ --().()o{)+ _ ........
(0000011I h ....
"
......,...........
~.i'
•
..
F.gwe22 MooiQIlleiSpn togell"" Igfoml a repeating chain (a .' .... 011· ... oM). The
maaool· ... ' ' make up !he polymer material that _can use. The ~ granules
in the pictI.e CWl be noelted down and mol'kled inIo:.ry ~ plastic item.
Formation of polyalkenes
New words
One of the reaC1ions that plodu~ polymers is
synthetic, man-made
rallE"d addition polymt'riUtion.
macromolecule: a 'Iery large
TIll.' monomers ln an addition polymeriutlon
molecule that conslsts of many
.ca.-tion always have a douhl... bond between the
smaller idenlical sut>-uolts
linked t09f!lher
carbon atoms. So, alkenes can und...rgo addition
fllOIlf>fT>el _ one small moleo.lle
polymerization.
!hal joins with othln like it to
~ loin tog"het" Qnly unlkr highPfl"SSUR' conditions an,J if thM'r' .. a otalyst
pair aII< oes: potymers II>at are
pfl'Sl"Itt. 1M ~ bond b~ wblm the
made from aI<en& ,.100 IOO'.S
rnol«ul.-s join togptntor. Sina thne polymft'
mol«uJ.-s aTe' made from ~ ttMoy an' a.bo known ~ pol)'a~. Some of
_.-
thE' most important
poI)~ at\"
inlrodUl'l"d on tIM' Jl('xt page.
"
('"~'::;;J
F~25(
-"""'"
PolyphBl
l'ulypht'Il}1
monom.-rs.
altl.'rnatiT'.J!:
UsM in pac
F~26F
~
TOPIC
8
Polyethene
Th~ simplest
pol)'Illl"I,
altffie to undl'rgo addition polym<"rization is E1hMl(' 10 form the
polyrthellf.", as "''!' '<;Ow in Suh-Iopk I:
H H H H H H
--
•
I
I
I
I
I
I
-c-c-C-C-c-C-
"'111111'"
H H H H H H
FIgure 23 Moo....' .. s 01 ethene join logetherto form potjelhetle.
11lnl" ~ ""' 00l:
Idc~ntil:..1ber.JUSl" ~ dWm ~ n<JC
iIlIlM samt length.
Polypropene
un<k'fgo addition poI)mmntion 10 form ~IM.".
rolypropene is a hardy poI}'tIlC'I', so it is oftnt uSl'd "it"", .......1. falij;ue or stres
might ~ anolhPt" t}'Jl'l' <If plank. So. it is used to m.ak.. >Qlff piptS,
I'tupm<."
rn()nI;)Inl."rS
Qoor;llo<yapp;>"'lI.ll', ropn 11ll! all}'thing with a p1astk
--
HHfHH'
I
,
I
I
I
hln~.
H
I
c-e-c---c---c---cI
I
I
H
eM
H
I
I
ell lo"
I
n !'.....s
eH.)
Figure 24 "The 'n' means that any number (up to tho\.Is.al>d,;j of the units can
included in one macromolecule.
Polychloroethene
--
Classification of plastics
Fonnatio
Most plastit"3 a,l.' madr frum chrmicals found in lh... naphtha f,action of tnId... oll.
Thry a.... classlfi.l'd lmo two main groups: lhl'mlOsns and fhnmoplasJics.
'Ibe diagram \
that join to II
dicatboX)'lk I
nIDoX)'lkxj
diamine(mc
functional gr"
join to each (l
water. Nylon
bc-n.- of tbl
P,operties
• C·
linking betvo ee, Ihe
carbon chains ($0
molecule is formed)
~-
•
•
• Nou.
'''g:1terunercus
carbon c::hahs my nenwine
• High molecUlar welght
.
Low moltclJlar w.,~
• Initially. the plastic: Is solid but
Initially, the plastoc .IS liquid or
melts when healed and can
ma"eable. but once It cures
be reshaped. Each material
(sets on tteati og). It teI'I'13ins i"I
has its own aiticaI
tehipe al...e.
solid
,.Ie.
......,,:--::11.
,
""'•.
',,}
-- .... --,
......
Advillltages
--
"""" "'"
""
•
•
•
•
•
Highly flexible
Keeps its shape
Cost-effective
""""" bo ..,.,...
•
• "'""'" bo
F\glKe 27 A. si
.-eprewnt
ear.
•
~
polyurethane
Formatiol
The diJlgnm b
~ Macromolecules
~~.
t1K' folkJo",ing qU6tklns on yow- "",n:
L soo.., howl."tht'nt' ~ addition poIrmt'ti.z;;(tion using structur.ll formulas.
2. LOOK at tltt' tahlt' abovt' to ansWl"r the following questions. Which typt' of
plastk (thermoset Of th..,rmoplastic) could be uM'd for:
ill plastlc bags
b) l;jtchm bowls
c) underground Wale piP"
d) rontaiM'n to staR' petrol~
AnS"l'fi
Fonnation of nylon and Terylene
Nylon and Terylenl.' at... forme<.! by a
cOlldensaHon polymerization ......ctkm.
In rondmsation poIymr-malion. two
dHfem:>t polymO!tS join togt1hn and t'llmirultt' a
:small molecule in the Procf'$S-
170
Top\( 8 ()rpnl< <h<'ml,,,y
New word
~
poIj"oe.izatioo,:
:a poIymeI" th:at soIteo. when
heated and 1o<Jil:iir_ ........
....,
a dioI (an aka
join to el('h 01
polYf'Stt'r 1>t'CI
( ,~,
diol
TOPIC
8
Formation and structure of nylon
_..
lL..x:I
of crude oil.
~
. . criy i'l'.ertv.ioe
_weight
....-:: is solid but
~andcan
• Iiach material
""'"
The dia1(ram below shows the \WO monomers
that join to make nylon. The monomers al"<' a
dica,boxylic acid (a carboxylic add with h.",
carboxylic acid fun<1:ionaJ groups) and a
diamine (an organic mola-ule with two -NH,
functional grou~). The monomers ar<.' able to
join to each other by eliminating a moi<.'mi<.' of
water. Nylon is dassified as a polyamjd<.'
be<:ause of the I':J{CO
. functional groups present in
r~e
--
,-.
~acturing
-<II~O<::"~N-o-11 '\'
-.- c--l:ll-cP
-,.-"
1',1!q.~
"
polyamide: a macromolecule in
which the monomer unils are
linked by amide bonds
pol'ye$ter. a macromolecule in
which the monomer units are
linked by ester groups
the macromolelule
T~is
The presence of
NHCO group make.
nylon a poiyamide
n~~o_n_~,6.,J
-:
0'
_ <:~
N-D-'r,-cII:
OH
"1
H
water
-c~P •
. .;·'oH
.~
:1 1
Anotner
When N ana G bond.
on., H,O molecule is
elimlnat.,d
type of nylon 1$
called nylon 6.6 (>9cau...
.,acl> or the monomers contribure
6 carbon atoms 10 t~e chain
dica~~~d"YliC ~
mille
New words
f1--Q-H
. and anot"'"
diamlne monomer
can react nere to
dic3rbo~ylic
acid
monomer can
react here ...
continue
I"" cl>aln
Figure 27 A simplifoed condensation reaetioo that produces nylon. The boxes
represent carbon chains that are not directly involved in the reaction.
Formation and structufe of Terylene
.aural formulas.
'YP' "'
._w""
--
• "'ilN!~tion:
The diagram b<.'low shows the two monomers that join to make Terykne. The
monon\{'rs an' a dicarboxylk acid (much like that ust'd ill the rea(tion for nylon) and
a dial (an akohol "ith t,m -Oil functional grou~). These monomers aft' also able to
join to ea(h other by eliminating a molaule of water. Terylene is c1assjfie<J as a
polyester b<.'cause of the .COO
. functionalgJoups pr=t in the macromole<:U1e
(
The presence of tne -COOR group
dicarboxylic
add
iol
._ ,
M>H ,t
o~
C
1>;«
nO an<l C band,
H,O molecul.. Is
eliminated
\.
c,p _
0"
mai<e~
Teryfene a
.,Terylene
"'
o-c:
0'
'0
,
_•• _-
(
Ano/her dicarbo~yilc
acid mOMmer can
rMcl I>ere ...
pclyester
water
°
,
-je
OH t
H-Q-H
... and another <1101
mOMmer can reaU I>ere
to continue II>" cl>a;n
Figure 28 A SImplified cOfldensatlon reaction that produces Terylene
Sub.topH:';
M>oomoll'<"Uloo lpolymers)
171
,~-:-I..
'
~ Nylon and Terylene
Biodeg
Arnwt'r 11K' foUo...ing qUl'St1om in p;aio.:
I. Ilaw many produc!S ..rf' lhnf' in .. ('Ondt'~Ik>n ~tlon .....~ion?
2. N~ nm ...... )~ in which condm5Oltion- and ~dltion poq'mC'1'lzation diff~
3. US(' a block <fuIgram 10 show Ilx- nrunu", of;
a) nl'lon
b) T('I'yk'"nl'.
ha"<,, a vari<.'ty of pro]"'rties that allows tlu~m to be uil<'d in many dilll'n'nt
allplklltiu'K PlaStil'S aIt' dasslfu'd into stovt'n K('neral groups. MOSt polymer
I'laslil'S ,"all be l"ff)"C1ed Into otl",. plastic products.
.
--
•
polyethylene (HOPE)
•
•
II
Polyvinyl chloride
(PVC. vinyl)
•
•
•
bottles
clear trays (toiletnes
""" 'oodJ
<OPE)
•
•
PolyPi ....., ......
•
•
lo" del ISiIy pot,edL)'Ieo 1ft
lP"l
-
(PS)
•
•
•
t-stWt fabric
Sf! ..illY bag filing
-"""'" --="--"""""'"
...-""'"'
-- --"""'"
""""' ....
.....
milk, juice and
"'"
deteoglllil and
""'" """ ""'"
CDboM8S
• prolllCUve packaging
On-lER: Plastics o1tw:lr
• custom packaging
than those IisIed aI:lo'o'e. or • bottles lor citrus juice
!tlaI are made of a mixlJ.we • nylon is used for ropes
oIlhe phstics 1 to 6
and other fabrics
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
refuse twls and bags
irrigation pipes
172
T'-SOIpnlrclkiilbtl)
-~
mvironm
-
shoppi<>g bags
human~
~.
.....
:,~
:::1
1'ol}"lDI
from petll
Im-ir Iolll
100 light!'
,"00 _
by """"
door mats
garOeI1 fencing
de«lmpo!
ronver.ed
mintrali 1
~binlW1ers
imgation pipes
...... ,lMlleB
botlles and coolliltle $
coates and boxes
picture frames
curtain rods
seedling trays
created hi
MOlE'lII
from ",1M
..., -.
biodo!pd
w;de1y0li
Natur
1111' main
carhoh}"d
Carboh
plastic type wood
Oarb"hyt:
material
formula. '
roml' frO!
Note: f'otjed .... oe is the COllect IUPAC name. but on practice. poryethyIeno is the
coo, ...... , fI;ItIle.. Si'nill.riy, poIytloOflJu Ie is the ......
f\3f11e for poIypmpene..
'.'i(lIl
~~:!"
Plastic pc
I'la~li('S
•
INt
IID:D
Uses of plastics and synthetic fibres
•
~sti<'s h.l
tMya~so:
TOPIC
8
Biodegradability of synthetic fibres
1--'
dlftl.'l".
Mastics haw hondrt'ds of uses in our ewrydar live5. Onl" of the miln fusons why
they ,,"' 50 useful is bc'a.uSC' th~ an- unn'aMi",. BUI 1h.15 is also a problWl. Plastics
Ilut an" truu...-n ,.... y do not break doo<-n or M """y btfioU$o!' thl")' "It' non_
biodegradable. So, most of tIM' pUl5tics thrown ....... y SO }'f'an ago sllU niSI In the
environment todity.
Old you know?
",w...,.
Plastic: ~ ¢ion aftect:I both the
Its and
I"ouman heoIlth. F'tasotIi::s thal ..-.:l up i'l rM!n or the
oceans can suftocate and choke n-.ine rinaIs..
....... laJd alii,. becoo.oelJapped In pt... to s. or
try to eat it. AI of ll'ois afIeeu Ihlllood chain. and
OU" heBIth.. This is why 01 is SO important that
~ pi......... aereeyded instuaof erdng
up poIubng nauar .....i ...' ... 'ts.
Polymer p1iStiCS, which "'"' mainly moi>de
flom pl'1roleum, art not biodt'gJadable becalU"
their long l'0]ym"r mol=..tles art 100 larse and
too lightly txmdro. togl'lher to \)(> broken apart
by decomJX>S'." mganbms. BUI, S(ientlsls have
created biodegradabl"!'!astics that tan
New won!
non-biodegrad3b1e: ~ a
subistar'lc$ carVIOI he brokefl
down naturally by microorganisms sueh ll$ b&eleria
decompost' whUe In a LandftlL These plaslks arc
converted into carbon dloxldf', wall'r and
minerals by micro-organlsms.
Mort' rea'I1l1y, SCiellllsts have created a pbstic
from wheal 0' cornstarch ....hieh is ellSily
~. This rlMlk" is l'<l1Itd poIy1.ktide (PU),
but beaU5le il is SO 1'XJl'CflSi'.~ 10 rnal.:.e. il ~ nol U5l'd
widely as a petrolE't.lm plastic ~lIIffit.
Natural macromolecules
F9R 29
~able
PtA
can be used to make almost <Jrl'f
eYeryday produet, but al II priI.:e.
1ht' main rompOfll:nu of ~l tht food W\, .... I ale
arboh}"dr.lln, protons and fJlts. All Ihr\'\' ~ made up of m.¥TOmOlc:cu1es.
Carbohydrnl:cs
....
Calboh}W"les conl:ain only aorbon, hrdrog<>n and oxygen. 1b<'y m'"t' a gtm'tal
faranda, (;,11,,.0,.. w~ J( is JI mullipl<' of ~ lbe carbobydratf"l Iml wt' ..al.all
cotIIl' from plana.. P1.... u produce I~ arboh)-drateo; through phol:osynlheis.
Th~ use nrbon dioxide (trom the ail). Will.... (from IhI' ground), mngy (from tb..
sun) and chlorophyll (green pigm..m found III an g:r~ planu) 10 ma.... g1Ul."'OS<',"
simpl.. carbohydral'"
The gJucow undef&OC':'l a mndensatkm (X>Iymerizallon reaction to form mort'
rompIu catbohydratn. ~ linkage in tl1ol' IyptS of arbohydnu.·s are ailed
glycosidic bonds.
.'.
...• Ho--GoU
that
FIgUre 30 The po/ymerization of glucose to fo<m ITlOAl complex carbohydrates
Proteins
~
building bkrls of protrins an' amino acids,
and contain carbon, h}'drogm, oxygrn and
nitrogm. Amino -.ids COlIl!line by rondmsation
polymt'l'Wllion. Tlw linl.: bm'o'l!m the Jndi<,idual
l1XJnOInt'IS is an :wilde link.. much likt ..~t .....
have SI:\'Il in tM suuetuR' of n)'lon.
<Un;
' ...
H
I
"
1<1
=tino aCId
.-,
H
qO: ItJ,.
I
qO
New word
glycosicic bond: 8 COIIalenI
bond !hal. links 8 carbohydrate
to another <'JlOIen"" Of
--
amino acid: a bo.ikIO-oIl block of
pICtei'llhal. ........ otaio .. bach -M\
and -coot-l1\n:ticw\8l {lI"Cq>S
fatty acid: a building block of
the fats IhaI _ frod in OUt
bodies and in OUt kIod
I't"tft<n
II;'"
'H 0
.. I,n
: I "
..... 1.'
...• I/~-~-( ~jl.;::;(N-~-C'O~l ..·_.. ·-t\I:' -~f*-C-'''' H_O_H
"
....'hom ..'" ~n •
""Y"'" ~ ' "
• If-O-Il
Using glucose and minerals from lhe soil, plants
also produc(' mat"fomolecules of proteins and
fats.
Products 4
th~
"""""so (hal )"OUI bI
Proteins: TheI
up (hI" ptol('\.Fat&: Th~ 3A1
3nd munogl\u
In Sub-topic 5.
eIill"r:'l (or ~
~ps_lxn".
\"'egetablfo oils II
Identifying t
ThI" pm<"\'5lo at I
products of
,strp I Boil thI
hydroll
Step 2 i'Iacco",
thebH
Step 3
FIQute 31 Amino acids undergo condensation poIymeo'iUtion 10 produce proteins..
Your body needs proteins for the ~ blood criIs In )'Q\Ir body. for your s.ldn and
bones, and for rrw>y ch<"lllical ~ in your body. FISh, rrd DlNI, ctlkkm,
milk and ~ an: SO~ aamples of foods rich In pr«riru.
fatly
acids
'k>-8
...,...u glycerol
10-
Agure 32 The fonnalion 01' fal$
174
Top!<' 0Ip>i< 0'
"'Y
"'0;:',0 :
_~
;•
,0 ,
~
fat •
_H
water
1'\oQ'iP
IOL 11:1
St." -I Plaa til
.........
-.......
."""
StepS Onaa
Stl'p6 ~d1
Fats
Fats an: eIilom, whkh mans thty an' fOf'lned by an 1I1oohol MId 11 atboxylic acid.
In this c~, lhl' almhol is gl}"«Tol and lhe lldds Me long·dlain acids alled fall}'
acids. Th~ join together by an estl'f linkage ~th(' saml' t)'pl' of linkagl' found in
Terylene - and ag3.in, water is ellmlmlled. In your body, f3.1S 3.1'(' used for l.'Ilergy
and to makl' ml'n.branl's for lhe cells In yOUT bod}".
Comlll
~
Activity 14
Answer lhl" foUl
1. Explain tIM
a) amIno"
2. .l.'=pbIn ..-m
l""f'I1
lhousl
3. uescrtbf- th
4.
sno... how:
comp~Qt
I>.M _
<
Products of hydrolysis
~rates
-'-----
--,
'"'"""
r:;;_d
~
""">d
.~
"'"
..a'"
skin amI
chickpn,
When ...."(' C"at food, Ib~ nrbohydnlts, pnxrin~ and rats ~ brobm down by
..nzymn or acidS- In ~a("h~, tiM' food mlUl undt'tgOa h}'droly$i~ ",action 'lO
thaI the ('O<\$titUPflI nUlnl'll" nn bt mad<- a,'ailablt.' 10 your body for absorption,
Carbohydrnles: carboltydrale$ are broken down illl<J tltpir glll{'O$(' eon~tituem$.
SO that your hody ('an uS(' thp glue{)$(' for energy.
F'rgleins: TIlcS(' ar~' brokpn down im" amino acids, whiclt your body u~ to builo
up t!\eo prolMnS it needs to bt ht.'althy.
FalS: Th~ at'\" broken down inlO IbMr fally acids
..nd mooogl)TI"l:ilH's (frorn It.. gl)'C'eml).
In Sub-topic S, '"' !foamt "'->1 1M bydrol)'$iS of
est('f5 (Of sapo::>nifi«llkm) to prod~:IOiIPfo-Th~
soaps .....p buy loday arc mainly lUlIodt.' from
''f'gc1ablt.' oils sucb as roronul oil and palm oil.
We 6r.;:[ learnt IIIboU: pape<
~
... Gtadelo.
Do you ,e"Bnbeo how to
c:aIcUale R, values?
IdOfitifying the products of hydrolysis
of palX"t ('hromatography can \)(> usc.oU to S('paral.... anoldemify til('
products of hydmlysts of carbohydralC'5 and prot.... in5.
Stl", I Boil th.... Cilrboh}'drat.... or protein with hydrodllonc acid so that Ibe
hydrolysis fl"Ktlon can taU pia«>.
~q> 2 Maa two 01 thtff spot> of the' mixtuI\" on titt' chromatogJalm)' paP'-'" at
ItHo 1NsriInc, and bbel them It. In C.
Skp 3 I'brf'spobofl.noYlTl9.lpn; and aminoadchon IhI> i:litsl'IiM, and IaIJl"i thftn I
10 x. ~ "'iU 1:x> ~ to idl'ntif)' ItHo amino adds and sugars In till" mixtun5.
Stpp 4 MKt" Ih("chromatography palll'f In lh.... sol'"t'ItI, Walch bow th.. w1wnt risl's.
Stl'll.'i Onc.... <'OIIlI'INr, remow till' papt"r and dry it.
Step 6 Sin("{" till' prodl,l(1S at.... colourlrss, tIl(" dri~'<l chromatogram is In'at("(\ with
another l'hrmical to pnx!ua." a roIoured compound. Ninhydtln produCl"S
purvlie spoIs witlt amino acids and n"5OIctnoillroducl"5 roIoufl'd spots with
sugars. C..ompare thl' pmitJons 0( tiM' unl:nown spoo. with thosl' of ttll' blown
spots to identiC}, the amino acids and till' sugars p<neDt itt th.. mi"lurl'.
TIl~'l'ron"ss
~ Natural macromolecules
...-o-H water
AnSWf'r ttHo foIlO1\'in~ qlM.'StiOlts on your 0""11:
I. f.,..plain the following h"rms:
a) amino add
h) gl)'cosldic bono
c) carbol1ydral<>.
2. Explain why ill'an be said Ihat nr10n 15 similar to a prnh'in, in c!WlIlk,,1 (erms.
{,\'Ml though 001.' is a natur.ll macromo1rnllo." arId thl' other is a s}"nthl'1ic fib......
3. l"),>,s('rihe the roll" of hydmlpis in digl"Stion uf food.
4. Show how gJUCOilC' undergoes rondt"nsation poiymPIiz.ation to form a more
romplf,x carlIoh)untt', using struc1ural fonnubs.
Sub_topic' ~la<._
..
~"l
,.);'+
8, >
TOPIC
~!I
<
175
Summary, revision and assessment
Summary
Carbol<)-Ii
• (·arbo..:
Saturatt'd aDd llD.'Mltur.ll.ted hrclronorboDS
•
•
•
•
•
•
~
bonding of carbon atoms to adi~t arbon atoms with <Uv.lIml bonds Is
ailed (';>.t~... tiOD.
It. h}'drG<"aJ'boD Is an cxganX' moI«'l.Ile ronuining only h}-drogm and arbon
,ltoms. 1bry aR' <.ia.s<ilied ~ ~ther.
» aliphatic (str.Ught·dwn hfd.r\X'artlom), 01
» lll'VJDati.. (rings of hydronrbons)
SD.tar.ttN hyclrocarbo~ront,lin only singk' bonds in 1M arllon chain
~Wtf'n th~ carbon atom~
Uouatura.ted h}'clronorbons ronlains at Inst on.. daubl.. OIlripl~ bond In
tn.. carbon dtain bo!1"'"ff'f! .... rbon "tom~
Th~ numb.-r of Clrbon "t0ll15 determint'S th~ prdix of th... l\ilffi~_
Alkan .... ha,,,, only singl... bonds in tM.-arbon chain and their naml'$ end in
-an~.
• Alkro.-s ha,... a doubl... bond in the ..arlxln chain and th... ir naml!'S ..nd In of'nl'.
• All.:.. n~ ar.. g..n{'rally umeactivl' lle<:,luS(' lheir doubl.. carbon bonds are stahl..
and (-annUl easily bt' btol.:en
• bun..·..,. an' otganic molt"Cull'S with the :;.am.. mulN;Ular formulal', bUI diffe~nt
structural formulal'.
• 'lltl' refining of crude oil is Gllril'd OUI by th.. I'tOCnS of fractional dist illation.
Homologous series
• A functional group;s a lNrtkul<lr Ixlnd, atom or group of alomS lhal is
rtsponsibl.. for thl' lNrtirular propf'lIin 01 thaI group of compounds.
• A homologous seri..s Is a family of orpnlc cornpounth that an be
rt"pl'nmlro by a gl'JlI"ni lonnula, with urn Inl'ffiOO having t1K' saml'
functional YOUI' and <Jmllar dlmllal propertin, but diJfl'l'l'Tt1 physial
,.."...
• As tht" chain ll'ngtb ~<lSe for moleruln ollh.. sam<: holt)Ologou$ S('rie:s, tht"
boiling and mritinl; poinb lnaeaK.
...
Alcohols (;oIkaJ:>ols)
• The alcobols an' a homolo&<Jus W"rin 0( organic cmnpoun<k conu,ming thl'
functional group: .QH.
• Alcohols are- mati''l'1y rNCIh'l' and Ulldt'fgo IhO' following n'<l<'tions:
combustion, nll'rlfication, detl)'dlatlon and oxidation.
176
'lopi<"8 {<-'h<=t>tJyl
Ihl' coni
nrl>on I
• <:atbox1l
• Carbox1l
~=
• SPltbe
,''"''''''
·A~
identia
• A mom
!lund to
• A pol)".
linJ.:ed 1II
• Poly.....
form a F
Ie"~etlon
• The Il:l.lIl
I~ts. All
• The pta
"""''''''
RevisKJ
."'.
1. P'Iopel
a) Wt
bl ....
" 1.
d) D<
.)
....
Rl
carboxylic acids (alkanoic acids)
_bonds is
_£XI carbon
• (:arbo"yli<- adds an- a homologous series of organic compounds that haw
the co"d""S<'d sttU(\ura! formula, R_COOH, whkh always occurs on the first
carbon in t h" chain. Th" g""",al fommla is Cnll"., COOli.
• Carboxylic acids an- ma,k by th<i' oxidation of alcohols.
• Carboxylic acids ....a(\ with alcohols in th" pr<i'S<i'nc~ of an acid l-atalyst to form
l'Sters.
Esters (alkanoates)
• l:St .. n have the fUll(\ional groul), II.·COO-R'. Th... simpl...
plNsant o<lours.
bond in
~sters
tend to haw
Macromolecules (polymers)
SynthcHc compounds are manmadt' compounds that arc form~-d by a
l"hemkal pro,""".
0
A macromo!cnde is a very large molKuJ... (hal (onsist, of many smallcr,
klenlkal slru<1ural sub-units [inkffi together.
0
A monomer is a molecule that forms til", basi{' unit for po]ymen. MOJlome"
hond tv other mOIl<lmers 10 form a Tl'peating chain mol("{111r, Of p"lym,-..
0
A polymer h a compound consisting uf laIg" mole.;ul...:; that aT<' made up of a
linked s<:-rics of {"I",aled simple munumerS.
0
Polymcr;7.aHon h a chemical pr<K"{"Ss that <'(lmbines st'Veral mOnOIDI''"' to
form a polymer or polymeric cOIDJxmlld. Therl.' at{- two polymerizatioll
reaction" condensation and addition polymerization.
• Th" main n>mponents of all the food you eat are {'arbohydra1{'S. protein. and
fah. All IhJ'fi" aT'" mad<.- up of macromolecules.
• Th<i' proC<.":lS of thin lay~r or paper chromatography can tw uS('{! to S<i'para1<' and
id<i'ntity th<i' l>rodm1s of hydrolysis of arbohydratl'S and prot<i'ins.
0
~endin
.. ax! in ....ne.
.~
stable
ilat different
6I:tillation.
that is
Revision exercises
_wries, the
-.ingthe
I. Propene is a hydro,:arbon that Is made by cracking I....trokum. Propane is
a gas that is used in gas cylinders for portabl" stoves.
(I)K
a) \'lrite down th" lllok'<."lllar formula of propene.
(2)('
b) r."plail1 how propane differs from propane.
c) To which homologou., series do (i) propane and (Ii) propene twlong' {2)C
(2)Ap
d) Draw the structural formulas of propane and propene.
e) K"plain which molf'<'ul<i' (Jl"'l'ane or propene) is unsaturated.
(2)AI'
Topic 8 (Cl><:mi,try)
177
Summary, revision and assessment continued
f) Addition r;>aMioilli arC po5IiiblC wIth one of th.. molKUJn. Which
moIl1'(UJ.. ('aJl undrrgo OIddilion reactions? lil~'.. a reason for youl
anm'er.
g) l'Top<"ne is a r1lOIl<>lm'f in th<" making of <TTtain tYllE"l of plastic.
i) Il<"scrl~ what a monomer Is.
ill Show thrl'<" units In th<" sttuClllR' of the Ions chain pol)'m..r.
iii) (;i", the nam.. of thC' polymC'r.
Assesslm
(2.)Ap
(I)K
(l)A.p
{11 K
B: <..:Il,COOIt
Ethyl haa
:I) Wlite.
bl Wrltle<l,
c)
sa.-:w I
2. ThesUU'l
2.. Consldn' the following organic comlloundS:
A: IICOOII
1. Wlit'll hn
A
<..:: lIaxx:IiFI-I,
ll: CI1,CIlFOOIl
F" CHSII,CIl,o"
a) Writ.. (\0>,'" the structur;ll fonnul;,. 01 an iwm... of F_
(l)S
h) Writ.. down tllE' JUPAt: (s)'stl'rnatic) "",ne of B.
(I)AD
c) Nam.. ttlE' homologous H'rin to which C tx-longs.
(I)K
d) Write 00-.,.." the.' rwneot tlle<lfg3Tlic acid USl'd in the p~fation ofe
(l)E
to) Writ.. <k,...." the narl"lf' for C.
(I)Ap
f) Whi..h compoull<h ~lon1!: to the same homologous SC'I"iel;? Kame the
--L
A
a) S~,
b) Wl-.dl
(2)An
$ol"TIl"l>.
c)
3. Tllf" polymer mown as NoT (TCT)'Itn<'1 h an pxample of a polyntN.
Poly('Slers arl' prepaT<"d by Ih.. WndeflS<llion pul)'menution 01 a
dicvboxylic add "ilh I diakoholldiol), C'.ompounth X and \' art' tn..
monomers uS<'<! III make l'ET.
",,,,..
o Canpl
" ....
ii) WlII
Compound \'; lIo..QI,t:II,-QII
a) Which of rh" "'OnOlllel'S, X or Y, is a diol?
c)
d)
..)
Gh~
gl~
I) ~
a r.. aSOn for you.
answer.
(2.1(:
Draw the structural formu].a. 01 the n~o repE'aling units of rhl' polyrn"r
forme<l ill thf' cnndenSOllion rt'oKtion
compound X and
,",'mpound Y.
(31S
Wtlle down th.. formula of th<" rnoIKUI.. thaI Is diminal<'d dutlllg th..
",aMi"n.
(lIS
E.rpIain. in 1<'I1m of In $IJl.I("1Urt', why PET poJ)'mm all' r{'()'Clable. ;2.IAp
Cooldrtn\.:s are oft~n sold in I'FT plasli<" bolll<'$. F.Jlplain ",hy thl' uS<" of
r .., ' hoitk's insl..a<! of glass bottlf's indirectly rrou(n greenhOWl' gas
<-missions trom trauspo" fu~ls.
(1)E
"",,,-..en
1301
178
1",,",," lOloooIotr)'l
To"""
.J """"
Compound X: HOOC'.-C.ll.-<':OOI\
b)
"'"'"
d) Dfz'I< a
ill S3, Many<qjl
:I) 110'1" dl
b) Wrlled
~po
,,) Write d
bUt·i ...
llinued
Which
byour
Assessment exercises
(2)Ap
(11 K
'mer.
(I)Ap
(11 K
1. When hexanoic acid wa<;ts with alcohol, X, <'thyl hexanoate is pnx.luc<'<l.
Ethyl h('xanoate is used ("ooomer,"ially as a fruil flavour.
a) Write down the JUPAC name for alcohol X.
b) Write down Ill", stoK!Ufal formula of l'thyl hexanoate.
c) Name Oil" uS(' (or till." compound~ in this homologous series.
2. Th<:
A
struC1UK~
~
H_C_H
~
(I)S
(l)AD
(11K
~ofC.
1 :"ame th<'
(2)An
of,
_Tareth"
lDir your
(2)(;
tbepoJymer
_ " and
(3)S
-.lduri"glhe
(l)S
.cvdable.
of some organi(' mokml<.'S at\, shown ""'low:
B
(2)Ap
.·the US(> of
wgas
~777
H-C-C-C-C-H
D
~AA8
E
c
7f,III'7
H-C-\-C-G-o-H
,L111it1j
" P
H-1-C
I
" '0-"
(lW
{I lAp
(l~"
(2)Ao
(1)(:
(lIe
a) Nanw compound ,\.
h) Which of tht> o;oml'ounds, A to E, bt'long to the same hOlllOlogous
wries?
. (2)Ap
(1)(;
c) To \'dlich homologous =ies does mmpound n bt'long?
d) Draw an isomer of rompound D.
(2)Ao
e) /)(>s("ribt' a test that you can perfonn to distinguish bt'tw{'('n
mmpounds B and D.
(4)Ap
r) Cvmpound D can und~rgo addition reactions.
i) Explain why Il ,an undNgo this type of 'Netioll.
(2)Ap
ii) Whi,h othe' rt"actant must be addffi to [) to form wmpl:>und C?
(1 )S
g) Compounds C and ~; react with ea,h other.
i) Name tht> t}'pe of rea<"tion that takes plal'e
(I)Ap
ii) Name tht> organk product prooul'oo by the reaction.
(2)'>
3. )',Ially organic {"(lmpolHHb have Slm("(ural isomers
a) lIow do Iwo "mnural isomers differ from each oth{'"f?
(2)('
b) Write down Ihe Slrucrurallormula 01 ONF. slru,IUral isomer ollhe
('Hmpound bUl-I.-('n .
0;) Wrile down th.... gen ral formula lor Ib.... homologous :;eriC'> of whkh
bUl-l--ene is a member.
(lIe
Total: 2S marks
(Ill::
130]
Topic 8 IChcmistryl
179
The Periodic Table althe Elements
"
" • • "
-j~
H
__.
,
,~11
I _ •
21
_...",_
~
'!K
_
'0
-Ii
~
q
~
~-
M
~
Ca- _
Sc 1 _
11 _
vier
Mn
F,
e
_ , _ ....
1
:0
~,
,n
111
1.!O
It
1lI
. . rr lit·..
~IRbSr
Y
I'·~..r
ZI
~
t.4o
NIl
1
,~,
,_I_~f_ _
' J1''--Qi_ f'18 !
133
fles
e-",
If'
Sa
ta,'tt1,Ta
""''''.-- _I.'.......
itI
,
~
~1
j
'~
Co
,~'
, ,..'
I
,:',
~ Cu
..... I ' =- :1
W,Rt,c.
~
•
let'
111$-
i"Pl
t
,_",\._, _ _ 1_'
If
.
'3
~
'30
'''l
'.
.,.. .
1.......
---_
...
-,-'"
6i
_"""""'*....-
Th
'"-
-.. '"
~.
n
11
'
~
"~,,,
~:
In
Sn
so
1ft
200l
~i
--
20l
....
_
I_"'&'
T1
I
;:
"'
Pb
-..
F
I'~
"
n
Sf
_
.'.
b:'~
Bi
,'a
~
'r'
:If
13'
I
T,
'''~,"
~o"
IV
....,
8r
Kr
....... -
.
1IIe
...
_
I
.'~
~
J.l
,Cd
;~
•
•
,j
I
~\:It:>H
f>
S
()I
_
,--"
So
" ..'
'" I,.
,,.;;;.., J!t. I."l.
It .."
IloI,to'
1_'
r.~.
Gt
-Ga jW--II
_HE
I ,~ I "
110-
m
Co
~
~
Zn
""
IW,.Ha
,,4
,
AI
'·"-I_I;...l,,ti-~' -
IlIG -:
O~.~
I.
~
-r ' ,Oi'1-'0f1-1Ot
lQ,Ru,fIl
P<l
AD
'~."'1'3.1
II
M
C
21
_
~
12
B
_
~
Ii'
I,
.~-
~
,~
,11
,
L ~-
.1_",,"_
Mg
-.-'0_
•Otw_. 1<:__ . . .
.Al<oI_
~
2'
Ha
, -...
i'''' ,
'oI1 .... ~
Y,I
--
M
I··
Po
At
""""'1_
XlI
~
-
~
PI>
-
Il;Z
,.
•- • -,-11
.
orHo
I"
Of
Eo
'_If",_
"1
£.
Fm
'-
'..
Tm
113
Vb,
lIS
1lI
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ill
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