ACIDS AND
BASES
1.1.10
1
Students should be able to:
 Know the formulae of common acids and bases.
 State that an acid releases H+ ions in aqueous solution.
 State that common bases are metal oxides, metal hydroxides and
ammonia.
 State that an alkali is a soluble base that releases OH- ions in
aqueous solution.
 State that a salt is produced when the H+ ion of an acid is replaced
by a metal ion or NH4+.
 Describe the reactions of an acid with carbonates, bases and alkalis
to form a salt.
 Understand that a base readily accepts H+ ions from an acid.
2
Acid & Bases
CONTENTS
• The Arrhenius Theory of acids and bases
• Brønsted-Lowry theory of acids and bases
• LEWIS THEORY – this is A2
• Strong acids and bases
• Weak acids
• Weak bases
• Hydrogen ion concentration and pH
3
Historic acid–base theories
1776 Lavoisier - he defined acids in terms of their containing oxygen
1810 Sir Humphry Davy - proved the lack of oxygen "acidity does not depend upon any particular elementary substance, but upon
peculiar arrangement of various substances".
Berzelius - stated “acids are oxides of nonmetals while bases are oxides of
metals”.
1838 Justus von Liebig – “an acid is a hydrogen-containing substance in which
the hydrogen could be replaced by a metal”
1884 Svante Arrhenius with Friedrich Wilhelm Ostwald established the
presence of ions in aqueous solution
Arrhenius - Nobel Prize in Chemistry in 1903 for "recognition of the
extraordinary services... rendered to the advancement of chemistry by his
electrolytic theory of dissociation".
4
THEORIES OF ACIDS AND BASES
The Arrhenius Theory of acids and bases
• Acids are substances which produce hydrogen ions in
solution.
• Bases are substances which produce hydroxide ions in
solution.
Neutralisation happens because hydrogen ions and
hydroxide ions react to produce water.
hydrogen ions + hydroxide ions  Water
H + (aq) + OH¯ (aq)  H2O (l)
5
Limitations of the theory
Hydrogen Chloride / Hydrochloric acid is neutralised by both
sodium hydroxide solution and ammonia and a solution of ammonia.
Word/symbol equations
sodium hydroxide + hydrochloric acid 
ammonia + hydrochloric acid 
(g)
g
NH4Cl(s)
Ammonia dissolves in water
HCl(aq)
+
NH4OH(aq)  NH4Cl(aq)
+ H2O(l)
6
The Bronsted-Lowry Theory of acids and bases
An acid is a proton (hydrogen ion) donor.
A base is a proton (hydrogen ion) acceptor.
Hydroxide ions are bases - they accept hydrogen ions from acids and form
water.
An acid produces hydrogen ions in solution - it reacts with the water
molecules by giving a proton to them.
hydrogen chloride gas dissolves in water to produce hydrochloric acid,
Hydroxonium ions, H3O+, are produced.
7
Hydroxonium ions, H3O+,
It is important to realise that hydrogen ions in solution, H+(aq) are hydroxonium ions.
8
The hydrogen chloride /
ammonia problem
If it is in solution, the ammonia accepts a proton from a hydroxonium ion
NH3 (aq) + H3O+(aq)
——>
NH4+(aq) + H2O(aq)
If the reaction is happening in the gas state, the ammonia accepts a proton
directly from the hydrogen chloride:
NH3 (g) + HCl(g) ——>
NH4+(s) + Cl-(s)
Either way, the ammonia acts as a base by accepting a hydrogen ion from an
acid.
9
ACIDS AND BASES
BRØNSTED-LOWRY THEORY
ACID
proton donor
HCl ——> H+(aq) + Cl¯(aq)
BASE
proton acceptor
NH3 (aq) + H+(aq)
——>
NH4+(aq)
10
ACIDS AND BASES
BRØNSTED-LOWRY THEORY
ACID
proton donor
HCl ——> H+(aq) + Cl¯(aq)
BASE
proton acceptor
NH3 (aq) + H+(aq)
Conjugate systems
Acids are related to bases
ACID
Bases are related to acids
BASE
——>
PROTON
+
PROTON
NH4+(aq)
+ BASE
ACID
11
ACIDS AND BASES
BRØNSTED-LOWRY THEORY
ACID
proton donor
HCl ——> H+(aq) + Cl¯(aq)
BASE
proton acceptor
NH3 (aq) + H+(aq)
Conjugate systems
Acids are related to bases
ACID
Bases are related to acids
BASE
——>
NH4+(aq)
PROTON
+
PROTON
+
CONJUGATE BASE
CONJUGATE ACID
For an acid to behave as an acid, it must have a base present to accept a proton...
HA
acid
example
+
B
base
CH3COO¯ + H2O
base
acid
BH+
+
A¯
conjugate conjugate
acid
base
CH3COOH
acid
+
OH¯
base
12
ACIDS AND BASES
LEWIS THEORY – this is A2
ACID
lone pair acceptor
BF3
H+
BASE
lone pair donor
NH3
H2O
LONE PAIR DONOR
LONE PAIR DONOR
AlCl3
LONE PAIR
ACCEPTOR
LONE PAIR ACCEPTOR
13
STRONG ACIDS AND BASES
STRONG
ACIDS
e.g.
completely dissociate (split up) into ions in aqueous solution
HCl ——> H+(aq) + Cl¯(aq)
MONOPROTIC
1 replaceable H
DIPROTIC
2 replaceable H’s
HNO3 ——> H+(aq) + NO3¯(aq)
H2SO4 ——> 2H+(aq) + SO42-(aq)
14
STRONG ACIDS AND BASES
STRONG
ACIDS
e.g.
completely dissociate (split up) into ions in aqueous solution
HCl ——> H+(aq) + Cl¯(aq)
MONOPROTIC
1 replaceable H
DIPROTIC
2 replaceable H’s
HNO3 ——> H+(aq) + NO3¯(aq)
H2SO4 ——> 2H+(aq) + SO42-(aq)
STRONG
BASES
e.g.
completely dissociate into ions in aqueous solution
NaOH
——> Na+(aq) + OH¯(aq)
15
WEAK ACIDS
Weak acids
partially dissociate into ions in aqueous solution
e.g. ethanoic acid
When a weak acid dissolves in
water an equilibrium is set up
CH3COOH(aq)
HA(aq) + H2O(l)
CH3COO¯(aq)
+
H+(aq)
A¯(aq) + H3O+(aq)
The water stabilises the ions
To make calculations easier
the dissociation can be written...
HA(aq)
A¯(aq) +
H+(aq)
16
WEAK ACIDS
Weak acids
partially dissociate into ions in aqueous solution
e.g. ethanoic acid
CH3COOH(aq)
When a weak acid dissolves in
water an equilibrium is set up
HA(aq) + H2O(l)
CH3COO¯(aq)
+
H+(aq)
A¯(aq) + H3O+(aq)
The water stabilises the ions
To make calculations easier
the dissociation can be written...
The weaker the acid
HA(aq)
A¯(aq) +
H+(aq)
the less it dissociates
the more the equilibrium lies to the left.
17
WEAK BASES
Partially react with water to give ions in aqueous solution
e.g. ammonia
When a weak base dissolves in water an equilibrium is set up
NH3 (aq)
+ H2O (l)
NH4+ (aq) + OH¯ (aq)
as in the case of acids it is more simply written
NH3 (aq) +
H+ (aq)
NH4+ (aq)
18
WEAK BASES
Partially react with water to give ions in aqueous solution
e.g. ammonia
When a weak base dissolves in water an equilibrium is set up
NH3 (aq)
+ H2O (l)
NH4+ (aq) + OH¯ (aq)
as in the case of acids it is more simply written
NH3 (aq) +
The weaker the base
H+ (aq)
NH4+ (aq)
the less it dissociates
the more the equilibrium lies to the left
19
Hydrogen ion concentration [H+(aq)]
Introduction
hydrogen ion concentration determines the acidity of a solution
hydroxide ion concentration determines the alkalinity
for strong acids and bases the concentration of ions is very much
larger than their weaker counterparts which only partially dissociate.
Strong / Weak
– depends on ionisation
concentrated / dilute
– depends on the
number of particles
in a set volume
20
Hydrogen ion concentration [H+(aq)]
pH
hydrogen ion concentration can be converted to pH
pH = - log10 [H+(aq)]
to convert pH into hydrogen ion concentration
[H+(aq)] = antilog (-pH)
in both the above, [ ] represents the concentration in mol dm-3
The calculation is A2 but the understanding is AS !
[H+]
100 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10 10-11 10-12 10-13 10-14
OH¯
10-14 10-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 10-0
pH
0
1
2
STRONGLY
ACIDIC
3
4
5
WEAKLY
ACIDIC
6
7
8
NEUTRAL
9
10
WEAKLY
ALKALINE
11
12
13
14
STRONGLY
ALKALINE
www.johnkyrk.com/pH.html
21
1.1.10 Acids and Bases
Key definitions
Tasks – page 22-23
an acid . .
a base . .
an alkali . . .
Examiners tips are . .
Worksheet
Questions : 1, 2
Rainbow fizz ?
22
REACTIONS OF HYDROCHLORIC ACID
Is a typical acid in dilute aqueous solution
HCl
——> H+ (aq)
+ Cl¯(aq)
Hydrogen chloride is a colourless
covalent gas; it is a poor conductor
of electricity because there are no
free electrons or ions present. It
has no action on dry litmus paper
because there are no aqueous
hydrogen ions present.
23
REACTIONS OF HYDROCHLORIC ACID
Is a typical acid in dilute aqueous solution
Hydrogen chloride is a colourless
covalent gas; it is a poor conductor
of electricity because there are no
free electrons or ions present. It
has no action on dry litmus paper
because there are no aqueous
hydrogen ions present.
HCl
——> H+ (aq)
+ Cl¯(aq)
If the gas is passed into water, the
hydrogen chloride molecules dissociate
into ions. The solution now conducts
electricity showing ions are present. For
each hydrogen chloride molecule that
dissociates one hydrogen ion and one
chloride ion are produced. The solution
turns litmus paper red because of the
H+(aq) ions.
24
REACTIONS OF HYDROCHLORIC ACID
Is a typical acid in dilute aqueous solution
Hydrogen chloride is a colourless
covalent gas; it is a poor conductor
of electricity because there are no
free electrons or ions present. It
has no action on dry litmus paper
because there are no aqueous
hydrogen ions present.
HCl
——> H+ (aq)
+ Cl¯(aq)
If the gas is passed into water, the
hydrogen chloride molecules dissociate
into ions. The solution now conducts
electricity showing ions are present. For
each hydrogen chloride molecule that
dissociates one hydrogen ion and one
chloride ion are produced. The solution
turns litmus paper red because of the
H+(aq) ions.
25
REACTIONS OF HYDROCHLORIC ACID
Is a typical acid in dilute aqueous solution
HYDROGEN CHLORIDE
colourless gas
covalent molecule
HCl(g)
poor
no reaction
HCl
——> H+ (aq)
+ Cl¯(aq)
HYDROCHLORIC ACID
Appearance
Bonding
Formula
Conductivity
Dry blue litmus
colourless soln.
aqueous ions
HCl(aq)
good
goes red
26
REACTIONS OF HYDROCHLORIC ACID
Is a typical acid in dilute aqueous solution
hydrogen chloride
hydrochloric acid
Appearance
colourless gas
colourless soln.
HCl
——> H+ (aq)
Bonding and formula
covalent molecule HCl(g)
aqueous ions HCl(aq)
Conductivity
poor
good
+ Cl¯(aq)
Dry litmus
no reaction
goes red
27
Practical Activities
Reactive Metals and Acids
Magnesium : Mg
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
•
Put 5 cm3 of HCl in a boiling tube
drop in the Mg strip
Seal with hand
Wait for 1 to 2 minutes – until the pressure builds up
Attempt to ignite the trapped gas
Record your observations
• The metal reactants – dissolves into the acid
• The metal disappears ?
Acid in excess?
• A clear colourless solution forms
A soluble compound is form – no precipitate / solid formed
• Effervescence occurs – a gas is produced
• It’s colourless, its flammable gas - squeaky pop inference – H2
magnesium + hydrochloric acid →
28
REACTIONS OF HYDROCHLORIC ACID
Metals
magnesium + hydrochloric acid ——> magnesium chloride + hydrogen
Mg(s)
1.
+
2HCl(aq)
——>
MgCl2(aq)
+
H2(g)
WRITE OUT THE BALANCED EQUATION FOR THE REACTION
29
REACTIONS OF HYDROCHLORIC ACID
Metals
magnesium + hydrochloric acid ——> magnesium chloride + hydrogen
Mg(s)
Mg(s)
1.
2.
+
+
2HCl(aq)
2H+(aq) + 2Cl¯(aq)
——>
——>
MgCl2(aq)
+
H2(g)
Mg2+(aq) + 2Cl¯(aq) + H2(g)
WRITE OUT THE BALANCED EQUATION FOR THE REACTION
DILUTE ACIDS AND SALTS CONTAIN IONS; WATER, HYDROGEN & CARBON DIOXIDE DON’T
30
REACTIONS OF HYDROCHLORIC ACID
Metals
magnesium + dil. hydrochloric acid ——> magnesium chloride + hydrogen
Mg(s)
Mg(s)
+
+
2H+(aq) + 2Cl¯(aq)
cancel ions
1.
2.
3.
——>
2HCl(aq)
Mg(s)
——>
+ 2H+(aq)
MgCl2(aq)
+
H2(g)
Mg2+(aq) + 2Cl¯(aq) + H2(g)
——>
Mg2+(aq) +
H2(g)
WRITE OUT THE BALANCED EQUATION FOR THE REACTION
DILUTE ACIDS AND SALTS CONTAIN IONS; WATER, HYDROGEN & CARBON DIOXIDE DON’T
CANCEL OUT THE IONS WHICH APPEAR ON BOTH SIDES OF THE EQUATION
31
Practical Activities
Bases and Acids
Insoluble Metal Oxide : Copper Oxide
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
Put ½ a spatula of CuO in a boiling tube
Add 5-10 cm3 HCl ( that’s about a 1/3 of a Boiling tube )
Mix by gentle agitation
Wait for the reaction – warm gently if required
Record your observations
• The metal oxide (black/grey power solid) reactants slowly
• It dissolves into the acid/reacts with the acid
• A clear ? Green/blue ? solution forms
A soluble compound is form – no precipitate / solid left is ?
• No Effervescence occurs – no gas is produced
• Acid in excess ?
copper(II) oxide + hydrochloric acid →
32
REACTIONS OF HYDROCHLORIC ACID
Basic Oxides
Insoluble oxides
copper(II) oxide
CuO(s)
Cu2+O2-(s)
+
+
hydrochloric acid
2HCl(aq)
+ 2H+(aq) + 2Cl¯(aq)
cancel ions
——>
——>
copper(II) chloride + water
CuCl2(aq)
——> Cu 2+ (aq) + 2Cl¯(aq)
O2- + 2H+(aq)
——>
+
+
H2O(l)
H2O(l)
H2O(l)
33
Volume of
Temperatur
Indicator
Practical Activities
Acid added
e
Colour
Metal Hydroxides and Acids
cm3
°C
soluble Metal hydroxide : sodium hydroxide : NaOH
Initial temp
0
Hydrochloric Acid : HCl : 1.0 M
• Put 25cm3 NaOH in insulated beaker 2add 2-3 drops of indicator
• Record initial temperature and colour4of the indicator
• Add 1.0 HCl 2 cm3 at a time – record the temperature
until you reach
• Add a maximum of 40 cm3 1.0 HCl
40
• Record any observations- results table
• Plot – SKETCH your results – on graph paper
• Volume v ∆T ( or just T ) – add indicator colour changes
• Does the max temperature correlate with the indicator change ?
• At what volume did the maximum ∆T occur
sodium hydroxide + hydrochloric acid →
34
Volume of
Acid added
cm3
Temperature
°C
0
Initial temp
Indicator
Colour
2
4
until you reach
40
35
REACTIONS OF HYDROCHLORIC ACID
Alkalis
sodium hydroxide + hydrochloric acid
NaOH(aq)
Na+(aq) + OH¯(aq)
cancel ions
+
HCl(aq)
+ H+(aq) + Cl¯(aq)
H+(aq) + OH¯(aq)
——> sodium chloride + water
——>
NaCl(aq)
+
——> Na+ (aq) + Cl¯(aq)
——>
H2O(l)
+
H2O(l)
H2O(l)
36
REACTIONS OF HYDROCHLORIC ACID
Alkalis
sodium hydroxide + hydrochloric acid
NaOH(aq)
+
Na+(aq) + OH¯(aq)
cancel ions
HCl(aq)
——> sodium chloride + water
——>
NaCl(aq)
+
H2O(l)
+ H+(aq) + Cl¯(aq) ——> Na+(aq) + Cl¯(aq) + H2O(l)
H+(aq) + OH¯(aq)
——>
H2O(l)
37
Practical Activities
Alkalis and Acids
Sparing soluble Metal Hydroxide : Magnesium Hydroxide
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
•
Put one a spatula of MgO / Mg(OH)2 in beaker/conical flask
Add about 25 cm3 of water and 2-3 drops of Universal Indicator
Add HCl slowly : that’s 2-3 cm3 at a time
Mix by gentle agitation
Stop when you have added about 30 cm3
Record your observations
•
•
•
•
•
•
The metal oxide/hydroxide (white power solid) does not readily dissolve
Alkalis solution formed
Acid reacts with alkali neutralizing it but on standing reverts back to alkali.
A soluble compound is form – no precipitate / solid left ?
No Effervescence occurs – no gas is produced
Acid in excess ?
38
REACTIONS OF HYDROCHLORIC ACID
Alkalis
magnesium hydroxide – add water . . Check pH
magnesium hydroxide + hydrochloric acid
Mg(OH)2(s)
Mg2+(aq) + 2 OH¯(aq)
cancel ions
+
2 HCl(aq)
+ 2 H+(aq) + 2 Cl¯(aq)
——> magnesium chloride + water
——>
MgCl2 (aq)
+ 2 H2O(l)
——> Mg2+(aq) + 2 Cl¯(aq)
2 H+(aq) + 2 OH¯(aq)
——>
+ 2 H2O(l)
2 H2O(l)
39
Practical Activities
Carbonates and Acids
Insoluble Metal carbonates : calcium carbonate: CaCO3
Hydrochloric Acid : HCl : 1.0 M
• Add 5 cm3 HCl ( that’s less than a 1/3 of a Boiling tube )
• Add universal indicator
• Put 4 - 5 lumps CaCO3 in a boiling tube
• Mix by gentle agitation
• Wait for the reaction to go to completion
• Test the gas with a lighted splint
• Record your observations
•
•
•
•
•
•
The solid CaCO3 reactants slowly
Effervescence occurs – a gas is produced . . Not flammable
Called CO2 – test ?
Universal indicator changes colour RED to PINK ? To . . . GREEN
It dissolves into the acid/reacts with the acid
A clear ? solution forms ?
A soluble compound is form – no precipitate / solid left is ?
• Acid in excess ?
40
REACTIONS OF HYDROCHLORIC ACID
Carbonates – add water . . . Check pH
calcium carbonate + hydrochloric acid ——> calcium chloride + carbon dioxide + water
CaCO3(s)
+
2HCl(aq)
Ca2+CO32-(s) + 2H+(aq) + 2Cl¯(aq)
cancel ions
——>
CaCl2(aq)
+
CO2(g) + H2O(l)
——> Ca2+(aq) + 2Cl¯(aq) + CO2(g) + H2O(l)
CO32- + 2H+(aq)
——>
CO2(g) + H2O(l)
Test for Carbon Dioxide
Calcium hydroxide + carbon dioxide ——> Calcium carbonate + water
Ca(OH) 2 +
CO2(g)
——>
CaCO3(s)
Ca2+(aq) + 2 OH¯(aq) + CO2(g) ——> Ca2+ (s) +
+ H2O(l)
+ CO 2-(s)
3
+ H2O(l)
2 OH¯(aq) + CO2(g) ——> CO32-(s) + H2O(l)
41
Practical Activities
Bubbling CO2 into water/lime water
Straws
Boiling tubes
Phenolphthalein indicator / universal indicator
Limewater
Tap water
• Put 5 cm3 of water in a boiling tube
• 2 drop of universal indicator
• Record your observations
•
•
•
•
Put 5 cm3 of lime water in a boiling tube
2 drop of phenolphthalein indicator
Record your observations
Why does the precipitate disappear ?
42
REACTIONS OF HYDROCHLORIC ACID
Carbonates – add water . . . Check pH
calcium carbonate + hydrochloric acid ——> calcium chloride + carbon dioxide + water
CaCO3(s)
+
2HCl(aq)
Ca2+CO32-(s) + 2H+(aq) + 2Cl¯(aq)
cancel ions
——>
CaCl2(aq)
+
CO2(g) + H2O(l)
——> Ca2+(aq) + 2Cl¯(aq) + CO2(g) + H2O(l)
CO32- + 2H+(aq)
——>
CO2(g) + H2O(l)
Hydrogen carbonates – add water . . . Check pH
Sodium hydrogen carbonate + hydrochloric acid ——> sodium chloride + carbon dioxide + water
NaHCO3(aq)
+
HCl(aq)
Na+ (aq) + HCO3¯ (aq) + H+(aq) + Cl¯(aq)
HCO3¯ (aq) +
——>
NaCl(aq)
+
CO2(g) + H2O(l)
——> Na+ (aq) + Cl¯(aq) + CO2(g) + H2O(l)
H+(aq)——>
CO2(g)
+
H2O(l)
43
REACTIONS OF HYDROCHLORIC ACID
What happens if you keep bubbling CO2 into water ?
carbon dioxide + water——> carbonic acid
CO2(g)
+
H2O(l)
——>
H2CO3(aq)
2 H2CO3 (aq) + CaCO3 (s) ——> Ca ( HCO3 )2 (aq) + CO2(g) +
Ca2+CO32-(s) + 2H+(aq) + CO32- (aq) ——>
H2O(l)
HCO3¯ (aq) + CO2(g) + H2O(l)
44
Practical Activities
ammonia and hydrochloric acid
conc. NH3/conc. HCl
2 gas jars. Universal indicator Paper
2 -3 drops in separate gas jars – check pH
• Invert one jar over the other.
• Record observations
NH3
HCl
45
REACTIONS OF HYDROCHLORIC ACID
ammonia
NH3(g)
+ hydrochloric acid ——> ammonium chloride
+
HCl(g)
——>
NH4Cl(s)
NH3 (g) + HCl(g) ——> NH4 +(s) + Cl¯(s)
46
REACTIONS OF HYDROCHLORIC ACID
Ammonium hydroxide
Ammonium hydroxide + hydrochloric acid ——> ammonium chloride + water
NH4OH(aq)
+
HCl(aq)
NH4+ (aq) + OH¯ (aq) + H+(aq) + Cl¯(aq)
——>
NH4Cl (aq) + H2O(l)
——> NH4 + (aq) + Cl¯(aq) + H2O(l)
cancel ions
OH¯(aq)
+ H+(aq)——>
H2O(l)
47
REACTIONS OF HYDROCHLORIC ACID
Metals
magnesium + hydrochloric acid ——> magnesium chloride + hydrogen
Basic Oxides
copper(II) oxide
+
hydrochloric acid
——>
copper(II) chloride + water
Alkalis
sodium hydroxide + hydrochloric acid
——> sodium chloride + water
Carbonates
calcium carbonate + hydrochloric acid ——> calcium chloride + carbon dioxide + water
Hydrogen carbonates
Sodium hydrogen carbonate + hydrochloric acid ——> sodium chloride + carbon dioxide + water
ammonia
ammonia
+ hydrochloric acid ——> ammonium salts
48
REACTIONS OF HYDROCHLORIC ACID
SUMMARY
METALS
react to give
a salt + hydrogen
METAL OXIDES
react to give
a salt + water
METAL HYDROXIDES
react to give
a salt + water
CARBONATES
react to give
a salt + water + carbon dioxide
HYDROGENCARBONATES
react to give
a salt + water + carbon dioxide
AMMONIA
reacts to give
an ammonium salt
49
Tasks . . . Page 24 - 25
Key definitions
a salt . .
an anion . .
a cation . . .
Examiners tips are . .
Worksheet – word equations . . to symbol equations
Questions : 1, 2
50
WORD EQUATION QU ESTION S (you might have to fit two words in a line space)
1)
zinc + hydrochloric acid ===> ?___________________________ + hydrogen
2)
?_______________________ + sulphuric acid ===> copper(II) sulphate + water + carbon dioxide
3)
magnesium oxide + ?___________________________ ===> magnesium nitrate + water
4)
zinc + sulphuric acid ===> zinc sulphate + ?___________________________
5)
magnesium hydroxide + hydrochloric acid ===> ?___________________________ + water
6)
?__________________ + nitric acid ===> copper(II) nitrate + water + ?__________________
7)
zinc carbonate + sulphuric acid ===> ?______________ + ?____________ + carbon dioxide
8)
iron + ?___________________________ ===> iron(II) chloride + hydrogen
9)
magnesium oxide + hydrochloric acid ===> ?____________________ + ?________________
10)
?_________________ + hydrochloric acid ===> calcium chloride + water + ?__________________
11)
?___________________________ + sulphuric acid ===> magnesium sulphate + hydrogen
12)
magnesium + nitric acid ===> ?___________________________ + hydrogen
13)
zinc hydroxide + ?___________________________ ===> zinc chloride + water
14)
?____________________ + hydrochloric acid ===> magnesium chloride + water + carbon dioxide
15)
aluminium + hydrochloric acid ===> ?___________________________ + hydrogen
16)
sodium hydroxide + hydrochloric acid ===> ?_______________________ + ?________________
17)
sodium carbonate + ?_________________ ===> sodium sulphate + water + ?________________
18)
?___________________________ + nitric acid ===> calcium nitrate + water + carbon dioxide
51
19) ?___________________________ + sulphuric acid ===> iron(II) sulphate + hydrogen
20) zinc oxide + ?___________________________ ===> zinc chloride + water
21) copper(II) carbonate + sulphuric acid ===> ?_____________________ + water + carbon dioxide
22) aluminium + ?___________________________ ===> aluminium sulphate + hydrogen
23) calcium oxide + hydrochloric acid ===> ?______________________ + ?_________________
24) magnesium hydroxide + ?________________ ===> magnesium sulphate + ?________________
25) ammonia + sulphuric acid ===> ?___________________________
26) ammonia + ?___________________________ ===> ammonium chloride
27) zinc hydroxide + sulphuric acid ===> ?_____________________ + ?______________
28) copper(II) oxide + hydrochloric acid ===> ?___________________________ + water
29) sodium hydroxide + sulphuric acid ===> ?___________________________ + water
30) sodium hydrogencarbonate + hydrochloric acid ===> ?______________ + ?_______________
+?________________
31) ammonia + ?___________________________ ===> ammonium nitrate
32) calcium oxide + ?_____________________ ===> calcium chloride + ?_____________________
33) aluminium hydroxide + nitric acid ===> ?___________________________ + water
34) calcium carbonate + ?________________ ===> calcium ethanoate + ?____________ + ?________________
35) ethanoic acid + magnesium ===> ?____________________ + hydrogen
36) _________________ + magnesium oxide ===> magnesium ethanoate + ?____________
37) sodium hydroxide + ?_______________ ===> ?_____ ethanoate + ?_____________
52
53
Now write the full symbol
equations
Check the formula of the
compounds
Make sure you balance the
equations
Add the state symbols
Most formulas you should
know but these may help
Formulas –
copper II hydroxide Cu(OH)2
lead II hydroxide Pb(OH)2
54
55
Practical Activities
Reactive Metals and Acids
Magnesium : Mg
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
Put 5 cm3 of HCl in a boiling tube
drop in the Mg strip
Seal with hand
Wait for 1 to 2 minutes – until the pressure builds up
Record your observations
• The metal reactants – dissolves into the acid
• The metal disappears ?
Acid in excess?
• A clear colourless solution forms
A soluble compound is form – no precipitate / solid formed
• Effervescence occurs – a gas is produced
• It’s colourless, its flammable gas - squeaky pop inference – H2
56
Practical Activities
Bases and Acids
Insoluble Metal Oxide : Copper Oxide
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
Put ½ a spatula of CuO in a boiling tube
Add 5-10 cm3 HCl ( that’s about a 1/3 of a Boiling tube )
Mix by gentle agitation
Wait for the reaction – warm gently if required
Record your observations
• The metal oxide (black/grey power solid) reactants slowly
• It dissolves into the acid
• A clear ? Green/blue ? solution forms
A soluble compound is form – no precipitate / solid left
• No Effervescence occurs – no gas is produced
• Acid in excess ?
57
Practical Activities
Metal Hydroxides and Acids
soluble Metal hydroxide : sodium hydroxide : NaOH
Hydrochloric Acid : HCl : 1.0 M
• Put 25cm3 NaOH in insulated beaker add 2-3 drops of indicator
• Record initial temperature
• Add 0.1 HCl 2 cm3 at a time – record the temperate
• Add a maximum of 40 cm3 0.1 HCl
• Plot your results
• Volume v ∆T – add indicator colour changes
• Record any observations
• Does the max temperature correlate with the indicator change ?
• At what volume did the maximum ∆T occur
58
Practical Activities
Alkalis and Acids
Sparing soluble Metal Hydroxide : Magnesium Hydroxide
Hydrochloric Acid : HCl : 1.0 M
•
•
•
•
•
•
Put one a spatula of MgO / Mg(OH)2 in beaker/conical flask
Add about 25 cm3 of water and 2-3 drops of Universal Indicator
Add HCl slowly : that’s 2-3 cm3 at a time
Mix by gentle agitation
Stop when you have added about 30 cm3
Record your observations
•
•
•
•
•
•
The metal oxide/hydroxide (white power solid) does not readily dissolve
Alkalis solution formed
Acid reacts with alkali neutralizing it but on standing reverts back to alkali.
A soluble compound is form – no precipitate / solid left ?
No Effervescence occurs – no gas is produced
Acid in excess ?
59
Practical Activities
Carbonates and Acids
Insoluble Metal carbonates : calcium carbonate: CaCO3
Hydrochloric Acid : HCl : 1.0 M
• Add 5-10 cm3 HCl ( that’s about a 1/3 of a Boiling tube )
• Add universal indicator
• Put 4 - 5 lumps CaCO3 in a boiling tube
• Mix by gentle agitation
• Wait for the reaction to go to completion
• Test the gas with a lighted splint
• Record your observations
•
•
•
•
•
•
The solid CaCO3 reactants slowly
Effervescence occurs – a gas is produced . . Not flammable
Called CO2 – test ?
Universal indicator changes colour RED to PINK ? To . . . GREEN
It dissolves into the acid/reacts with the acid
A clear ? solution forms ?
A soluble compound is form – no precipitate / solid left is ?
• Acid in excess ?
60
Practical Activities
Bubbling CO2 into water/lime water
Straws
Boiling tubes
Phenolphthalein indicator / universal indicator
Limewater
Tap water
• Put 5 cm3 of water in a boiling tube
• 2 drop of universal indicator
• Record your observations
•
•
•
•
Put 5 cm3 of lime water in a boiling tube
2 drop of phenolphthalein indicator
Record your observations
Why does the precipitate disappear ?
61
Practical Activities
ammonia and hydrochloric acid
conc. NH3/conc. HCl – in bottle with glass droppers
2 Gas Jars
Universal indicator Paper – wet it first ?
Put 2 -3 drops of HCl/NH3 in separate gas jars – check pH
• Invert one jar over the other. ( HCl on top ? )
• Record observations
NH3
HCl
62
Practical Activities
Reactive Metals and Acids
Magnesium : Mg ribbon
Hydrochloric Acid : HCl : 1.0 M
boiling tube
Wooden splints
Bases and Acids
Insoluble Metal Oxide : Copper Oxide
Hydrochloric Acid : HCl : 1.0 M
boiling tube
Metal Hydroxides and Acids
soluble Metal hydroxide : sodium hydroxide : NaOH 1.0 M
Hydrochloric Acid : HCl : 1.0 M
insulated beaker
Thermometer
25 / 50 cm3 measuring cylinders
Alkalis and Acids
Magnesium Hydroxide - solid
Hydrochloric Acid : HCl : 1.0 M
conical flask
universal indicator solution
Carbonates and Acids
Insoluble Metal carbonates : calcium carbonate: CaCO3 - solid
Hydrochloric Acid : HCl : 1.0 M
universal indicator solution
Boiling tube
63
Bubbling CO2 into water/lime water
Straws
Boiling tubes x 2
Phenolphthalein indicator / universal indicator
Limewater
ammonia and hydrochloric acid
conc. NH3/conc. HCl – in bottle with glass droppers
2 Gas Jars
Universal indicator Paper
64
‘Name’ of Acid
Formula
ion
Hydrochloric acid
HCl
Cl
Carbonic acid
H2CO3
CO3
Nitric acid
HNO3
NO3
Nitrous acid
HNO2
NO2
Sulphuric acid
H2SO4
SO42
Sulphurous acid
H2SO3
SO32
Ethanoic acid
CH3COOH
CH3COO
Name of ion
-
chloride
-
Carbonate (V)
-
Nitrate (v)
-
Nitrate (III)
-
Sulphate (VI)
-
Sulphate (IV)
-
ethanoate
65
Exercise 1 - Deduce the formulae of the following compounds:
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
q)
r)
Sodium oxide
Calcium hydroxide
Ammonium nitrate
Potassium carbonate
Strontium sulphate
Ammonium sulphate
Hydrochloric acid
Rubidium hydroxide
Magnesium carbonate
Calcium nitrate
Sulphuric acid
Ammonium chloride
Nitric acid
Potassium sulphate
Magnesium oxide
Caesium bromide
Barium sulphate
Strontium nitrate
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
q)
r)
Na2O
Ca(OH)2
NH4NO3
K2CO3
SrSO4
(NH4)2SO4
HCl
RbOH
MgCO3
Ca(NO3)2
H2SO4
NH4Cl
HNO3
K2SO4
MgO
CsBr
BaSO4
Sr(NO3)2
base
base
salt
base
salt
salt
acid
base
base
salt
acid
salt
acid
salt
base
salt
salt
salt
66
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
q)
r)
Na2O
Ca(OH)2
NH4NO3
K2CO3
SrSO4
(NH4)2SO4
HCl
RbOH
MgCO3
Ca(NO3)2
H2SO4
NH4Cl
HNO3
K2SO4
MgO
CsBr
BaSO4
Sr(NO3)2
base
base
salt
base
salt
salt
acid
base
base
salt
acid
salt
acid
salt
base
salt
salt
salt
67
Exercise 3 – Write balanced symbol equations, with state symbols, for the following reactions:
a) Nitric acid with potassium
b) hydroxide solution
c) Sulphuric acid with sodium hydroxide solution
d) Hydrochloric acid with calcium hydroxide powder
e) Nitric acid with calcium oxide powder
f)
Hydrochloric acid with barium oxide powder
g) Sulphuric acid with magnesium oxide powder
h) Nitric acid with calcium carbonate powder
i)
Hydrochloric acid with barium carbonate powder
j)
Sulphuric acid with sodium carbonate solution
k) Nitric acid with ammonia solution
l)
Sulphuric acid with ammonia solution
m) Hydrochloric acid with ammonia solution
68
a) HNO3(aq) + KOH(aq)  KNO3(aq) + H2O(l)
b) H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + H2O(l)
c) 2HCl(aq) + Ca(OH)2(s)  CaCl2(aq) + H2O(l)
d) 2HNO3(aq) + CaO(s)  Ca(NO3)2(aq) + H2O(l)
e) 2HCl(aq) + BaO(s)  BaCl2(aq) + H2O(l)
f)
H2SO4(aq) + MgO(s)  MgSO4(aq) + H2O(l)
g) 2HNO3(aq) + CaCO3(s)  Ca(NO3)2(aq) + CO2(g) + H2O(l)
h) 2HCl(aq) + BaCO3(s)  BaCl2(aq) + CO2(g) + H2O(l)
i)
H2SO4(aq) + Na2CO3(aq)  Na2SO4(aq) + CO2(g) + H2O(l)
j)
HNO3(aq) + NH3(aq)  NH4NO3(aq)
k) H2SO4(aq) + 2NH3(aq)  (NH4) 2SO4(aq)
l)
HCl(aq) + NH3(aq)  NH4Cl(aq)
69
Titration Questions
Page 37/38
Questions 5, 6, 7
70