Answer all questions in the spaces provided.
1 (a) (i) State what is meant by partition coefficient.
.................................................................................................................................
…..............................................................................................................................
............................................................................................................................. [1]
Ammonia is soluble in both water and organic solvents.
An aqueous solution of ammonia is shaken with the immiscible trichloromethane.
The mixture is left to reach equilibrium.
Samples are taken from each layer and titrated with dilute hydrochloric acid.
• A 25.0 cm3 sample from the trichloromethane layer requires 13.0 cm3 of 0.100
mol dm-3 HCl to reach end-point.
• A 10.0 cm3 sample from the aqueous layer requires 12.5 cm3 of 0.100 mol dm-3
HCl to reach end-point.
(ii) Calculate the partition coefficient, Kpartition, of ammonia between trichloromethane
and water.
Kpartition = .............................. [2]
(ii) Butylamine, C4H9NH2, is also soluble in both water and organic solvents.
Suggest how the value of Kpartition of butylamine between trichloromethane and
water would compare to the value of Kpartition calculated in (ii). Explain.
.................................................................................................................................
…..............................................................................................................................
............................................................................................................................. [2]
2
(b) (i) Explain why butylamine is basic.
.................................................................................................................................
…..............................................................................................................................
............................................................................................................................. [1]
(ii) Write an equation to show butylamine reacting as a base.
............................................................................................................................. [1]
(iii) State how the basicity of butanamide compares to that of butylamine.
............................................................................................................................. [1]
(iv) State a reagent for the conversion of butanamide into butylamine.
............................................................................................................................. [1]
[Total: 9]
3
2 An electrochemical cell is constructed using two half cells: Sn4+/Sn2+ and Al3+/Al.
(a) State the material used for the electrode in each half-cell.
Sn4+/Sn2+ half-cell ….....................................................................................................
Al3+/Al half-cell ..............................................................................................................
[1]
(b) The cell is operated at 298 K.
The Al3+/Al half-cell has standard concentrations.
The Sn4+/Sn2+ half-cell has [Sn4+] = 0.300 mol dm-3 and [Sn2+] = 0.150 mol dm-3.
(i) Use the Nernst equation to calculate the electrode potential, E, of the Sn4+/Sn2+
half-cell under these conditions.
E = .............................. V [2]
(ii) Calculate the Ecell under these conditions.
Ecell = .............................. V [1]
(iii) Write an equation for the overall reaction that occurs
............................................................................................................................. [2]
4
(c) Aluminium is produced industrially by electrolysis of a melt containing large amounts
of Al3+ ions.
Calculate the mass of aluminium that is obtained when a current of 300 000 A is
passed for 24 hours. Give your answer to three significant figures.
mass = .............................. units = .............................. [4]
(d) Explain why chromium metal cannot be obtained by the electrolysis of dilute
aqueous chromium(II) sulfate. Your answer should include data from the Data
Booklet.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
................................................................................................................................. [2]
[Total: 12]
5
3 Thermodynamics can be used to assess the feasibility of a process.
(a) The table below lists equations for five processes.
For each process, predict the sign of DS.
sign of DS
process
NaBr(s) + (aq) ® NaBr(aq)
H2O(l) ® H2O(g)
2H2(g) + O2(g) ® 2H2O (g)
CoCl2(s) + 6H2O(l) ® CoCl2.6H2O(s)
[2]
(b) Ethanol can be combusted as shown in the equation.
CH3CH2OH(l) + 3O2(g) ® 2CO2(g) + 3H2O(l)
Standard entropies are shown below in the table.
substance
CH3CH2OH(l)
O2(g)
CO2(g)
H2O(l)
Sq, J K-1 mol-1
161
205
214
70
Calculate the standard entropy change, DSq, for this reaction.
DSq = .............................. J K-1 mol-1 [2]
(c) The combustion of ethanol is an exothermic reaction. This reaction occurs spontaneously at low temperature but does not occur at high temperature. Explain why.
......................................................................................................................................
......................................................................................................................................
................................................................................................................................. [2]
6
(d) The decomposition of calcium carbonate is an endothermic reaction.
CaCO3(s) ® CaO(s) + CO2(g)
DH = +178 kJ mol-1 and DS = +159 J K-1 mol-1
Calculate the minimum temperature at which this reaction becomes feasible.
Show all your working.
[3]
[Total: 9]
7
4 Much of the preparation of evidence to solve crimes relies on instrumental analysis. This
question deals with some of the techniques used.
(a) Electrophoresis can be used to separate amino acids produced by hydrolysis of
proteins. The amino acids are placed in a buffered solution in an electric field. In a
solution of given pH, what two factors affect the movement of a given amino acid?
(i) ............................................................................................................................ [1]
(ii) ............................................................................................................................ [1]
(b) NMR and mass spectrometry are also used in detection of certain molecules,
particularly those containing hydrogen atoms.
(i) Explain how and why the NMR spectrum of propanal, CH3CH2CHO, would be
different from that of propanone, CH3COCH3, which contains the same atoms.
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
............................................................................................................................ [2]
(ii) Explain how and why the mass spectrum of the two compounds in (i) would be
different.
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
............................................................................................................................ [2]
8
(c) At one time, bromomethane, CH3Br, was widely used to control pests in agriculture.
It is now known to break down in the stratosphere and contribute to the destruction
of the ozone layer.
Samples can be screened for traces of bromomethane by subjecting them to mass
spectrometry.
(i) Which peak(s) would show the presence of bromine in the compound?
............................................................................................................................ [1]
(ii) How could you tell by studying the M and M+2 peaks that the compound
contained bromine rather than chlorine?
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
............................................................................................................................ [2]
[Total: 9]
9
10
10
5 The
initial
reaction
rate
for propanone
and iodine
in acid
solution
is measured
in aLQ
series
KHLQLWLDO
LQLWLDO
UDWHRI
RI
UHDFWLRQ
IRUSURSDQRQH
SURSDQRQH
DQG
LRGLQH
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LVPHDVXUHG
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DVHULHV
VHULHVRI
RI
10LRGLQH
44 77KH
UDWH
UHDFWLRQ
IRU
DQG
LQ
VROXWLRQ
LV
LQ D
experiments
at
a
constant
temperature.
of experiments
constanttemperature.
temperature.
experiments at
at aa constant
4
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7
catalyst
experiments at a constant temperature. ++++catalyst
&+ &2&+ + I
&+ &2&+ I+I
&+33&2&+33 + I22
&+33&2&+22I+I
++ catalyst
7
KHUDWHHTXDWLRQZDVGHWHUPLQHGH[SHULPHQWDOO\WREHDVVKRZQ
&+
&2&+
+
I
&2&+2I+I
The
rate
equation
was
experimentally
determined
as&+
the 3following.
3
3
2
7KHUDWHHTXDWLRQZDVGHWHUPLQHGH[SHULPHQWDOO\WREHDVVKRZQ
rate = k>&+ &2&+ @>+ ]
7KHUDWHHTXDWLRQZDVGHWHUPLQHGH[SHULPHQWDOO\WREHDVVKRZQ
rate = k>&+ 3&2&+ 3@>++]
+
3
3
(a) 6WDWHWKHRUGHURIUHDFWLRQZLWKUHVSHFWWR
rate = k>&+3&2&+3@>++]
(a) 6WDWHWKHRUGHURIUHDFWLRQZLWKUHVSHFWWR
(a) State
the order of reaction with respect to
Ɣ
&+ &2&+ ..........................................................................................................................
6
3
3
ƔWDWHWKHRUGHURIUHDFWLRQZLWKUHVSHFWWR
&+3&2&+
•(a) CH
3COCH
3 ............................................................................................................
3 ..........................................................................................................................
•
Ɣ &+
I 3.........................................................................................................................................
&2&+3 ..........................................................................................................................
I2Ɣ
Ɣ ............................................................................................................................
I 2 .........................................................................................................................................
•
+
+
HƔƔ
….........................................................................................................................
........................................................................................................................................
I++ .........................................................................................................................................
+
DQGVWDWHWKHRYHUDOORUGHURIWKLVUHDFWLRQ
...............................................................................
and Ɣ
the
overall
order of this reaction is ….....................................................................
........................................................................................................................................
+
–2
•(b) the
concentration
of I2 is 1.25
x 10
10–33-2is
mol
dm
–3
–1
1.50
u s-3
10
mol dm–3–3
Ɣ
WKHFRQFHQWUDWLRQRI&+
3&2&+
mol
dm
7
KHUDWHRIWKLVUHDFWLRQLVu
–2when
&2&+
is
1.50
u
10
Ɣ
W
KHFRQFHQWUDWLRQRI&+
–2
–3 mol dm
+
-1
-3
3
3
Ɣ concentration
WKHFRQFHQWUDWLRQRII
is 1.25
u 10–2mol
moldm
dm–3.
• the
of H is 27.75
x 10
2
Ɣ
+2 ........................................................................................................................................
DQGVWDWHWKHRYHUDOORUGHURIWKLVUHDFWLRQ ...............................................................................
[2]
[2] [2]
DQGVWDWHWKHRYHUDOORUGHURIWKLVUHDFWLRQ ...............................................................................
[2]
-3
-3 -1
(b) The
of this reaction is 5.40 x 1010
mol
–3
moldm
dm–3–3ss–1–1 when
when
(b) rate
7KHUDWHRIWKLVUHDFWLRQLVu
–3
mol dm
whendm-3
7KHUDWHRIWKLVUHDFWLRQLVu
•(b) the
concentration of CH3COCH310
is 1.50
x 10s-2 mol
Ɣ
KHFRQFHQWUDWLRQRII
dm
+ 1.25 u 10 –1
–3
2 is
–3
Ɣ WWKHFRQFHQWUDWLRQRI&+
WKHFRQFHQWUDWLRQRI+
is 7.75 u 10–1mol
mol
dm–2
.
u dm
10
Ɣ
+ 3&2&+3 is 1.50
–3 mol dm
Ɣ
W
KHFRQFHQWUDWLRQRI+
is
7.75
u
10
mol
. State the unit of k.
–2 reaction.
–3
(i) Calculate
the
rate
constant,
k,
for
this
Ɣ WKHFRQFHQWUDWLRQRII2 is 1.25 u 10 mol dm
+
(i) WKHFRQFHQWUDWLRQRI+
&DOFXODWHWKHUDWHFRQVWDQWkIRUWKLVUHDFWLRQ6WDWHWKHXQLWVRIk.
Ɣ
is 7.75 u 10–1 mol dm–3.
(i)
&DOFXODWHWKHUDWHFRQVWDQWkIRUWKLVUHDFWLRQ6WDWHWKHXQLWVRIk.
(i) &DOFXODWHWKHUDWHFRQVWDQWkIRUWKLVUHDFWLRQ6WDWHWKHXQLWVRIk.
k = ..............................
k = ..............................
units
..............................
k = ..............................
[1]
k ===..............................
units
..............................
[2]
units = .............................. [1] [2]
units = ..............................
(ii) &RPSOHWHWKHWDEOHE\SODFLQJoneWLFN LQHDFKURZWRGHVFULEHWKHHIIHFWRIdecreasing
[2]
(ii) &WKHWHPSHUDWXUHRQWKHUDWHFRQVWDQWDQGRQWKHUDWHRIUHDFWLRQ
RPSOHWHWKHWDEOHE\SODFLQJoneWLFN LQHDFKURZWRGHVFULEHWKHHIIHFWRIdecreasing
(ii) Complete
the
table
below
by
placing
one
tick
(Ö)
in
each
row
to
describe
the
WKHWHPSHUDWXUHRQWKHUDWHFRQVWDQWDQGRQWKHUDWHRIUHDFWLRQ
(ii) &RPSOHWHWKHWDEOHE\SODFLQJoneWLFN LQHDFKURZWRGHVFULEHWKHHIIHFWRIdecreasing
effectWKHWHPSHUDWXUHRQWKHUDWHFRQVWDQWDQGRQWKHUDWHRIUHDFWLRQ
of decreasing temperature
on the rate
constant and theincreases
rate of reaction.
decreases
QRFKDQJH
decreases
QRFKDQJH
increases
rate constant
decreases
QRFKDQJH
increases
rate constant
UDWHRIUHDFWLRQ
rate
constant
UDWHRIUHDFWLRQ
[1]
[1]
UDWHRIUHDFWLRQ
[1] [1]
10
11
)URPWKHUHVXOWVDJUDSKLVSURGXFHGZKLFKVKRZVKRZWKHFRQFHQWUDWLRQRII
(c) (c)
From
the results, a graph is produced which shows how the concentration
of I2
2FKDQJHVGXULQJ
the
reaction.
changes during the reaction.
11
(c) )URPWKHUHVXOWVDJUDSKLVSURGXFHGZKLFKVKRZVKRZWKHFRQFHQWUDWLRQRII2FKDQJHVGXULQJ
the reaction.
[I2]
[I2]
0
0
time
0
0
time
Describe
how this graph could be used to determine
the initial rate of the reaction.
'HVFULEHKRZWKLVJUDSKFRXOGEHXVHGWRGHWHUPLQHWKHLQLWLDOUDWHRIWKHUHDFWLRQ
'HVFULEHKRZWKLVJUDSKFRXOGEHXVHGWRGHWHUPLQHWKHLQLWLDOUDWHRIWKHUHDFWLRQ
.....................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.....................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
................................................................................................................................
[2]
.............................................................................................................................................. [2]
.............................................................................................................................................. [2]
(d) On the axes below, sketch a graph to show how the initial rate changes with different
(d) 2QWKHD[HVEHORZVNHWFKDJUDSKWRVKRZKRZWKHLQLWLDOUDWHFKDQJHVZLWKGLIIHUHQWLQLWLDO
(d) 2QWKHD[HVEHORZVNHWFKDJUDSKWRVKRZKRZWKHLQLWLDOUDWHFKDQJHVZLWKGLIIHUHQWLQLWLDO
initial
concentration
of CH3COCH
in this reaction.
in 3this reaction.
FRQFHQWUDWLRQVRI&+ &2&+
FRQFHQWUDWLRQVRI&+
3
3 3 in this reaction.
3&2&+
rate
rate
0
0
0
[CH3COCH3]
[1]
0
[1]
[CH3COCH3]
[1]
© UCLES 2019
11
9701/42/M/J/19
[Turn over
12
(e) The rate of a reaction between metal ions was studied. The following three-step
(e) 7KHUDWHRIDUHDFWLRQEHWZHHQPHWDOLRQVZDVVWXGLHG7KHIROORZLQJWKUHHVWHSPHFKDQLVP
mechanism
has been suggested. Step 1 is the rate-determining step.
KDVEHHQVXJJHVWHGIRUWKLVUHDFWLRQ6WHSLVWKHUDWHGHWHUPLQLQJVWHS
step 1
Ce4+0Q2+
Ce3+0Q3+
step 2
Ce4+0Q3+
Ce3+0Q4+
VWHS
0Q4+ + Tl +
Tl 3+0Q2+
(i) ([SODLQWKHPHDQLQJRIWKHWHUPrate-determining step.
(i) Explain the meaning of the term rate-determining step.
.............................................................................................................................................
……......................................................................................................................
....................................................................................................................................... [1]
……................................................................................................................. [1]
(ii)
Use this mechanism to
(ii)
mechanism
to
Use this Ɣ
GHWHUPLQHWKHRYHUDOOHTXDWLRQIRUWKLVUHDFWLRQ
•
determine the overall equation for this reaction
.............................................................................................................................................
……............................................................................................................. [1]
•
Ɣ
VXJJHVWWKHUROHRI0Q2+ ions in this mechanism. Explain your answer.
suggest the role of Mn2+ ions in this mechanism. Explain your answer.
.............................................................................................................................................
.........................................................................................................................
.............................................................................................................................................
.........................................................................................................................
.............................................................................................................................................
.........................................................................................................................
.................................................................................................................... [1]
[Total: 11]
Topic: Kinetic
Total= 13 +11 = 24
12
[2]
[Total: 11]
6 A mixture of three compounds, J, K and L, was analysed by thin layer chromatography
using a polar stationary phase and a non-polar mobile phase. The three compounds all
have similar molecular masses. The resulting chromatogram is shown below.
(a) Identify which spot corresponds to each compound.
[2]
(b) Explain your answers to (a).
......................................................................................................................................
......................................................................................................................................
................................................................................................................................ [2]
Serotonin is converted by enzymes in the liver to compound M.
13
(c) By reference to the Data Booklet, suggest how the infra-red spectrum of M would
differ from that of serotonin.
......................................................................................................................................
......................................................................................................................................
................................................................................................................................ [2]
(d) The proton NMR spectrum of M dissolved in CDCl3 shows eight peaks due to the
eight different types of proton present in the molecule.
The proton NMR spectrum of M dissolved in D2O was recorded.
Predict the number of peaks that would be seen in the proton NMR spectrum of M in
D2O. Explain your answer.
......................................................................................................................................
......................................................................................................................................
................................................................................................................................ [2]
(e) Compound M can be polymerized under certain conditions to form polymer N.
Polymer N is biodegradable, unlike polyethene which is not.
Explain why N is biodegradable.
......................................................................................................................................
......................................................................................................................................
................................................................................................................................ [2]
[Total: 10]
14
12 12
7
Asparagine
and and
valine
are two
naturally
occurring
amino
acids.
7 Asparagine
Asparagine
andvaline
valine
are
naturally
occurring
amino
7
are
twotwo
naturally
occurring
amino
acids.acids.
O
O
O
O
O
OH OH
O
OH OH
NH2 NHNH
2 NH2
2
NH2 NH2
asparagine
asparagine
valine
valine
(a) (a)
GiveGive
the molecular
formula
of asparagine.
Give
the molecular
formula
ofof
asparagine.
(a)
the
molecular
formula
asparagine.
..............................................................................................................................................
[1][1][1]
................................................................................................................................
..............................................................................................................................................
(b) (b)
Name
all ofall
the
groups
in aninasparagine
molecule.
(b)
Name
of
the
groups
an
asparagine
molecule.
Name
all
offunctional
thefunctional
functional
groups
in an
asparagine
molecule.
................................................................................................................................
..............................................................................................................................................
[2][2][2]
..............................................................................................................................................
(c) (c)
Draw
the structure
of the
dipeptide
formed
by valine
asparagine.
(c)
Draw
the
ofof
the
dipeptide
formed
by valine
and
asparagine.
Draw
the structure
structure
the
dipeptide
formed
byand
valine
and
asparagine.
The
peptide
bond
should
shown
displayed
and
be
clearly
labelled.
The The
peptide
bondbond
should
be shown
displayed
and and
should
beshould
clearly
labelled.
peptide
should
bebe
shown
displayed
should
be clearly
labelled.
[2] [2]
A solution
of valine
in water
a buffer
solution.
(d) (d)
A solution
of valine
in water
acts acts
as aas
buffer
solution.
Explain
is meant
a buffer
solution.
(i) (i)
Explain
whatwhat
is meant
by aby
buffer
solution.
[2]
.............................................................................................................................................
.............................................................................................................................................
(d) A
solution
of valine in water acts as a buffer solution.
(i)
Explain
what is meant by a buffer solution.
.............................................................................................................................................
.............................................................................................................................................
…..............................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
[2] [2]
…..............................................................................................................................
H
two equations
to explain
valine
canas
act
a buffer.
the formula
H2NCHRCO
(ii) (ii)
WriteWrite
two equations
to explain
how how
valine
can act
a as
buffer.
Use Use
the formula
H2NCHRCO
2H 2
for
valine
in
your
equations.
for ............................................................................................................................
valine in your equations.
[2]
.............................................................................................................................................
.............................................................................................................................................
15
.............................................................................................................................................
.............................................................................................................................................
[2] [2]
(ii) Write two equations to explain how valine can act as a buffer. Use the formula
H2NCHRCO2H for valine in your equations.
…..............................................................................................................................
..................................................................................................................................
[2]
(e) Each valine molecule has one chiral carbon atom.
Draw three-dimensional diagrams to show the two optical isomers of valine.
The (CH3)2CH group can be represented as R.
[2]
(f) Asparagine is hydrolysed when heated with aqueous sulfuric acid.
Write an equation for this reaction.
................................................................................................................................ [2]
[Total: 13]
16
7
Phenylethanone
importantchemical
chemical with
with many
8 4Phenylethanone
is is
ananimportant
manyuses.
uses.
phenylethanone
CH3
C
O
(a) Phenylethanone can be synthesised using benzene as one of the starting materials.
(a) Phenylethanone can be synthesised using benzene as one of the starting materials.
Identify the other reagents used and describe any essential reaction conditions.
Identify the other reagents used and describe any essential reaction conditions.
......................................................................................................................................
....................................................................................................................................................
.................................................................................................................................
[2]
.............................................................................................................................................. [2]
(b) Phenylethanone is treated separately with three reagents.
(b)
Phenylethanone
separately
withformula
three reagents.
Complete
the tableistotreated
give the
structural
of one organic product formed and
the Complete
name of mechanism
If there
no the
reaction,
write
‘no reaction’.
the table, forinvolved.
each reagent,
to is
give
structural
formula
of one organic product
formed and the name of the mechanism involved. If there is no reaction you should write ‘no
reaction’.
reagent
reagent
organic product
organic product
name of mechanism
name of mechanism
chlorine gas at 10°C in
the presence
of qC
UVinlight
chlorine
gas at 10
the
presence of ultra-violet light
a mixture of concentrated
a mixture of concentrated nitric
nitric
and sulfuric
and
sulfuric
acids atacids
50 qC at
50°C
bromine water
bromine water
[5]
17
[5]
8
(c) Phenylethanone reacts with HCN in the presence of a small amount of NaCN.
(c) Phenylethanone reacts with HCN in the presence of a small molecule NaCN.
(i)
8
Name the mechanism of this reaction.
(i) Name the mechanism of this reaction.
(c) Phenylethanone reacts with HCN in the presence of a small amount of NaCN.
....................................................................................................................................... [1]
............................................................................................................................ [1]
(ii)
(i) Name the mechanism of this reaction.
Draw the mechanism of this reaction below. Include all relevant charges, dipoles, lone
pairs and curly arrows. Your mechanism should show the catalytic role of CN– ions.
....................................................................................................................................... [1]
(ii) Draw
the mechanism
of this
reaction.
Include
relevant
charges,charges,
dipoles,dipoles,
lone lone
(ii) Draw
the mechanism
of this
reaction
below.all
Include
all relevant
phenylethanone
intermediate
product
–
pairs and curly arrows. Your mechanism should show
the catalytic role of CN ions.
pairs and curly arrows. Show the catalytic role of CN ions.
phenylethanone
CH3
intermediate
product
C
O CH
3
C
O
[4][4]
(d) Phenylethanone can be used as a starting material to make phenylethene in a two-step
[4]
synthesis.
(d) Phenylethanone can be used as a starting material to make phenylethene in a twostep process.
phenylethene
(d) Phenylethanone can be used as a starting material to make phenylethene in a two-step
phenylethanone
D
synthesis.
H
H
CH3
step 1
step 2
C phenylethene
C
C
phenylethanone
D
H H
H
O CH
3
step 1
step 2
C C
C
H
(i) Draw theOstructure of compound D in the box.
[1]
(i) Draw the structure of compound D in the box above.
(ii)
[1]
Identify a suitable reagent for step 1.
(i)
Draw
the structure
of compound
.......................................................................................................................................
[1] [1]
(ii) Identify
a suitable
reagent
for step 1.D in the box.
(ii)
Identify
a suitable
reagent
for step
(iii).............................................................................................................................
Identify
a suitable
reagent
for step
2. 1.
[1]
.......................................................................................................................................
.......................................................................................................................................
[1] [1]
(iii) Identify a suitable reagent for step 2.
(iii)
Identify a suitable reagent for step 2.
.............................................................................................................................
[1]
.......................................................................................................................................
[1]
18
(iv) State the number of peaks in the C-13 NMR spectrum of phenylethene.
............................................................................................................................. [1]
(v) Suggest C-13 chemical shift ranges expected for the different types of carbon
environment in phenylethanone.
…..............................................................................................................................
…..............................................................................................................................
…..............................................................................................................................
............................................................................................................................ [2]
[Total: 18]
19
9 (a) Sketch the shape of a d orbital.
Draft Prelim 2020, JC2 Chemistry
3
6
(a) 6NHWFKWKHVKDSHRIDGRUELWDO
[1]
(b) Some elements with d orbital can be classified as transition elements.
(i) Briefly explain the term transition element.
[1]
..................................................................................................................................
(b) (i) ([SODLQZKDWLVPHDQWE\WKHWHUPtransition element.
............................................................................................................................. [1]
.............................................................................................................................................
....................................................................................................................................... [1]
Transition
elements can form complex ions which contain ligands.
7UDQVLWLRQHOHPHQWVFDQIRUPFRPSOH[LRQVZKLFKFRQWDLQOLJDQGV
(ii) Name the type of bonding that occurs between a ligand and a transition element.
(ii) 1DPHWKHtype of bondingWKDWRFFXUVEHWZHHQDOLJDQGDQGDWUDQVLWLRQHOHPHQW
............................................................................................................................. [1]
....................................................................................................................................... [1]
(c) Give the formulae of two oxides of iron. State the oxidation number of iron in each
(c) *LYHWKHIRUPXODHRIWZRR[LGHVRILURQ6WDWHWKHR[LGDWLRQQXPEHURILURQLQHDFKFRPSRXQG
compound.
.....................................................................................................................................
....................................................................................................................................................
................................................................................................................................[1]
[1]
..............................................................................................................................................
(d) &2DQG&1–DUHPRQRGHQWDWHOLJDQGV
-
(d) CO and CN are monodentante ligands.
&RPSOHWHWKHWDEOHIRUWKHIROORZLQJWZRFRPSOH[HV
Complete the table below for the following two complexes.
metal ion
OLJDQG
co-ordination
QXPEHU
1L2+
CO
4
Fe3+
&1–
IRUPXODRI
complex ion
FKDUJHRI
complex ion
3[2]
[2]
20
7
(e) Transition element complexes can exhibit stereoisomerism. [Cu(H2O)4(NH3)2]2+ and
(e) 7UDQVLWLRQHOHPHQWFRPSOH[HVFDQH[KLELWVWHUHRLVRPHULVP>&X +2O)4 1+3)2]2+DQG3W 1+3)2Cl 2
Pt(NH
2Cl2 show the same type of isomerism.
show
the3)sameW\SHRILVRPHULVP
(i) Name this type of isomerism.
(i) 1DPHWKLVW\SHRILVRPHULVP
............................................................................................................................ [1]
....................................................................................................................................... [1]
(ii)(ii)&Complete
RPSOHWHWKHWKUHHGLPHQVLRQDOGLDJUDPVRIWKHWZRLVRPHUVIRU>&X
+2O)4 1+3)2]2+ and
the diagrams below for the Cu and Pt complexes.
3W 1+3)2Cl 2.
Cu
Cu
Pt
Pt
[2]
[2]
[Total: 9]
END OF PAPER
21