A Level Chemistry 9701 Paper 42, Oct/Nov 2023

Question paper and mark scheme100 marks9 questions

Solve it on ExamPal

Practise

Untimed. Write on the paper and check as you go.

Start

Exam

Timed, with a clock you set, like sitting the real paper.

Start

Opens full screen.

Papers open in

Download PDF Mark scheme

100%

Opening the question paper

Read as textThe questions and the mark scheme as plain text. Easier to read on a phone.

Question paper

9701/42 · Oct/Nov 2023

Download PDF

Propanone, $C H_{3} C O C H_{3}$ , reacts with iodine, $I_{2}$ , in the presence of an acid catalyst. $C H_{3} C O C H_{3} + I_{2} \to C H_{3} C O C H_{2} I + H^{+} + I^{-}$ The rate equation for this reaction is shown. $rate = k [C H_{3} C O C H_{3}] [H^{+}]$

Complete Table 1.1 to describe the order of the reaction. Table 1.1

order of the reaction with respect to $[C H_{3} C O C H_{3}]$
order of the reaction with respect to $[I_{2}]$
order of the reaction with respect to $[H^{+}]$
overall order of the reaction

[2]

b(i)

An experiment is performed using a large excess of $C H_{3} C O C H_{3}$ and a large excess of $H^{+} (a q)$ . The initial concentration of $I_{2}$ is $1.00 \times 10^{- 5} mol {dm}^{- 3}$ . The initial rate of decrease in the $I_{2}$ concentration is $2.27 \times 10^{- 7} mol {dm}^{- 3} s^{- 1}$ . Use the axes to draw a graph of $[I_{2}]$ against time for the first 10 seconds of the reaction.

[1]

b(ii)

State whether it is possible to calculate the numerical value of the rate constant, $k$ , for this reaction from your graph. Explain your answer.

[1]

The experiment is repeated at a different temperature. The initial concentrations of $H^{+}$ ions, $I_{2}$ and $C H_{3} C O C H_{3}$ are all $0.200 mol {dm}^{- 3}$ . The value of $k$ at this temperature is $2.31 \times 10^{- 5} {mol}^{- 1} {dm}^{3} s^{- 1}$ . Calculate the initial rate of this reaction. $rate = ..................................... mol {dm}^{- 3} s^{- 1}$

[1]

d(i)

The experiment is repeated using an excess of $H^{+} (a q)$ . The new rate equation is shown. $rate = k_{1} [C H_{3} C O C H_{3}]$ The value of $k_{1}$ is $1.1 \times 10^{- 3} s^{- 1}$ . Calculate the value of the half-life, $t_{\frac{1}{2}}$ . $t_{\frac{1}{2}} = ...................................................... s$

[1]

d(ii)

Use your answer to (i) to draw a graph of $[C H_{3} C O C H_{3}]$ against time for this reaction. The initial value of $[C H_{3} C O C H_{3}]$ on your graph should be $0.200 mol {dm}^{- 3}$ . The final value of $[C H_{3} C O C H_{3}]$ on your graph should be $0.0250 mol {dm}^{- 3}$ .

[1]

e(i)

A four-step mechanism is suggested for the overall reaction. $C H_{3} C O C H_{3} + I_{2} \to C H_{3} C O C H_{2} I + H^{+} + I^{-} rate = k [C H_{3} C O C H_{3}] [H^{+}]$ Part of this mechanism is shown. $step 1: C H_{3} C O C H_{3} + H^{+} \to C H_{3} C^{+} (O H) C H_{3}$ $step 2: C H_{3} C^{+} (O H) C H_{3} \to C H_{3} C (O H) = C H_{2} + H^{+}$ $step 3: \to$ $step 4: C H_{3} C^{+} (O H) C H_{2} I \to C H_{3} C O C H_{2} I + H^{+}$ Write an equation for step 3.

[1]

e(ii)

Suggest the slowest step of the mechanism. Explain your answer.

[1]

e(iii)

Identify one conjugate acid-conjugate base pair in the mechanism. $conjugate acid .......................................... conjugate base ..........................................$

[1]

Benzoic acid, $C_{6} H_{5} C O O H$ , is a weak acid. The $K_{a}$ of benzoic acid is $6.31 \times 10^{- 5} mol {dm}^{- 3}$ at $298 K$ . A $1.00 {dm}^{3}$ buffer solution is made at $298 K$ containing $1.00 g$ of $C_{6} H_{5} C O O H$ and a slightly greater mass of sodium benzoate, $C_{6} H_{5} C O O^{-} N a^{+}$ . This buffer solution has a pH of 4.15.

Define buffer solution.

[1]

b(i)

Write equations to show how this solution acts as a buffer solution when the named substances are added to it: dilute aqueous sodium hydroxide

[1]

b(ii)

dilute aqueous nitric acid.

[1]

Calculate the $H^{+}$ concentration and the $C_{6} H_{5} C O O H$ concentration in the buffer solution described. Use the expression for the $K_{a}$ of $C_{6} H_{5} C O O H$ to calculate the concentration of $C_{6} H_{5} C O O^{-} N a^{+}$ in the buffer solution. Show your working and give each answer to a minimum of three significant figures. $[H^{+}] = .............................. mol {dm}^{- 3}$ $[C_{6} H_{5} C O O H] = .............................. mol {dm}^{- 3}$ $[C_{6} H_{5} C O O^{-} N a^{+}] = .............................. mol {dm}^{- 3}$

[3]

A $10.0 {cm}^{3}$ sample of the buffer solution is mixed with $10.0 {cm}^{3}$ of $1.00 mol {dm}^{- 3} KOH$ . Both solutions are at $298 K$ . A reaction is allowed to occur without stirring. Two observations are recorded: ● the temperature, after the reaction is complete, is fractionally above $298 K$ ● the pH, after the reaction, is greater than 13. Explain these two observations.

[2]

e(i)

Magnesium benzoate, $M g (C_{6} H_{5} C O O)_{2}$ , has a solubility in water of less than $1.00 g {dm}^{- 3}$ at $298 K$ . $K_{s p} = [M g^{2 +}] [C_{6} H_{5} C O O^{-}]^{2} = 1.76 \times 10^{- 7} at 298 K$ Calculate the solubility of $M g (C_{6} H_{5} C O O)_{2}$ in water at $298 K$ . Give your answer in $g {dm}^{- 3}$ . Show your working. [ $M_{r}$ : $M g (C_{6} H_{5} C O O)_{2}$ , 266.3] $solubility = .............................. g {dm}^{- 3}$

[2]

e(ii)

An excess of $M g (C_{6} H_{5} C O O)_{2}$ is added to a sample of $0.50 mol {dm}^{- 3} {MgSO}_{4}$ at $298 K$ . State whether the equilibrium concentration of $M g (C_{6} H_{5} C O O)_{2}$ is higher than, the same as, or lower than your answer to (i). Explain your answer. The concentration is ..................................................................... the concentration in (i). explanation ........................................................................................................................ ...........................................................................................................................................

[1]

Some electrode potentials are shown in Table 3.1. Table 3.1

electrode reaction	$E^{⊖} / V$
$V^{2 +} + 2 e^{-} ⇌ V$	$- 1.20$
$V^{3 +} + e^{-} ⇌ V^{2 +}$	$- 0.26$
$V O^{2 +} + 2 H^{+} + e^{-} ⇌ V^{3 +} + H_{2} O$	$+ 0.34$
$V O_{2}^{+} + 2 H^{+} + e^{-} ⇌ V O^{2 +} + H_{2} O$	$+ 1.00$
$F e^{2 +} + 2 e^{-} ⇌ F e$	$- 0.44$
$F e^{3 +} + 3 e^{-} ⇌ F e$	$- 0.04$
$F e^{3 +} + e^{-} ⇌ F e^{2 +}$	$+ 0.77$
$2 H^{+} + 2 e^{-} ⇌ H_{2}$	$0.00$
$C l O^{-} + H_{2} O + 2 e^{-} ⇌ C l^{-} + 2 O H^{-}$	$+ 0.89$

a(i)

Complete the diagram to show a standard hydrogen electrode. Label your diagram. Identify all substances. You do not need to state standard conditions.

[1]

a(ii)

An electrochemical cell is set up using an $F e^{3 +} / F e^{2 +}$ electrode and a standard hydrogen electrode. Identify the positive electrode in the electrochemical cell and the direction of electron flow in the external circuit. positive electrode .............................................................................................................. Electrons flow from the .............................. electrode to the .............................. electrode.

[1]

b(i)

The vanadium-containing species in the electrode reactions given in Table 3.1 are $V$ , $V^{2 +}$ , $V^{3 +}$ , $V O^{2 +}$ and $V O_{2}^{+}$ . Identify one vanadium-containing species that does not react with $F e^{2 +}$ ions under standard conditions. Use data from Table 3.1 to explain your answer.

[1]

b(ii)

Identify all the vanadium-containing species that will react with $F e^{2 +}$ ions under standard conditions.

[1]

b(iii)

Write an equation for one of the possible reactions identified in (ii).

[1]

c(i)

Another electrochemical cell is set up using an $F e^{3 +} / F e^{2 +}$ electrode and an alkaline $C l O^{-} / C l^{-}$ electrode. The concentration of $F e^{3 +}$ is 1000 times greater than the concentration of $F e^{2 +}$ in the $F e^{3 +} / F e^{2 +}$ electrode. All other conditions are standard. Use the Nernst equation to calculate the $E$ value of the $F e^{3 +} / F e^{2 +}$ electrode. Show your working. $E = .............................. V$

[2]

c(ii)

Write an equation for the reaction that occurs in the cell, under these conditions.

[1]

Another electrochemical cell is set up using an $F e^{2 +} / F e$ electrode and an alkaline $C l O^{-} / C l^{-}$ electrode under standard conditions. Calculate the value of $Δ G^{⊖}$ for the cell. $Δ G^{⊖} = .............................. kJ {mol}^{- 1}$

[3]

A solution of iron(II) sulfate, $F e S O_{4} (a q)$ is electrolysed with iron electrodes. Under the conditions used, no gas is evolved at the cathode. A current of $0.640 A$ is passed for $17.0 minutes$ . The mass of the cathode increases by $0.185 g$ . Use these results to calculate an experimental value for the Avogadro constant, $L$ . Show your working. $L = {.............................. mol}^{- 1}$

[3]

f(i)

Iron(II) chloride, $F e C l_{2}$ , is oxidised by chlorine to form iron(III) chloride, $F e C l_{3}$ , under standard conditions. $2 F e C l_{2} (s) + C l_{2} (g) \to 2 F e C l_{3} (s) Δ H^{⊖} = - 128 kJ {mol}^{- 1}$ Table 3.2

species	$S^{⊖} / J K^{- 1} {mol}^{- 1}$
$C l_{2} (g)$	223
$F e C l_{2} (s)$	120
$F e C l_{3} (s)$	142

Use Table 3.2 and other data to calculate the Gibbs free energy change, $Δ G^{⊖}$ , for this reaction. Show your working. $Δ G^{⊖} = .............................. kJ {mol}^{- 1}$

[3]

f(ii)

Predict whether this reaction becomes more or less feasible at a higher temperature. Explain your answer. The reaction becomes .............................. feasible. explanation ........................................................................................................................ ...........................................................................................................................................

[1]

The structure of the polydentate ligand, $E D T A^{4 -}$ , is shown in Fig. 4.1. Fig. 4.1 The stability constants, at $298 K$ , of five octahedral complexes are given in Table 4.1. Table 4.1

complex	$K_{stab}$
$[C u (E D T A)]^{2 -}$	$6.31 \times 10^{19}$
$[C r (E D T A)]^{2 -}$	$1.00 \times 10^{13}$
$[C r (E D T A)]^{-}$	$1.00 \times 10^{24}$
$[F e (E D T A)]^{2 -}$	$2.00 \times 10^{14}$
$[F e (E D T A)]^{-}$	$1.26 \times 10^{25}$

Define stability constant.

[1]

Calculate the oxidation states of $C u$ in $[C u (E D T A)]^{2 -}$ and $C r$ in $[C r (E D T A)]^{-}$ . $C u ..............................$ $C r ..............................$

[1]

Deduce the number of lone pairs donated by each $E D T A^{4 -}$ ligand in a single $[F e (E D T A)]^{2 -}$ complex ion.

[1]

Identify the most stable complex in Table 4.1. Explain your choice.

[1]

In a solution at equilibrium at $298 K$ , $[[C u (H_{2} O)_{6}]^{2 +}] = 3.00 \times 10^{- 10} mol {dm}^{- 3}$ and $[E D T A^{4 -}] = 5.00 \times 10^{- 12} mol {dm}^{- 3}$ . Use the expression for $K_{stab}$ to calculate the concentration of $[C u (E D T A)]^{2 -}$ in this solution. Show your working. $[[C u (E D T A)]^{2 -}] = .............................. mol {dm}^{- 3}$

[2]

A solution of $[C u (E D T A)]^{2 -}$ ions is pale blue while a solution of $[C u (N H_{3})_{4} (H_{2} O)_{2}]^{2 +}$ ions is deep blue. Explain this difference in colour.

[2]

Some of the ionic compounds of Group 2 elements undergo thermal decomposition. Thermal decomposition of solid anhydrous magnesium ethanedioate, $M g C_{2} O_{4}$ , occurs above $650^{\circ} C$ . The products are magnesium oxide and a mixture of two different gases, one of which gives a white precipitate with saturated calcium hydroxide solution.

Complete the equation for the thermal decomposition of $M g C_{2} O_{4}$ . $M g C_{2} O_{4} \to$

[1]

Suggest which of $M g C_{2} O_{4}$ or $C a C_{2} O_{4}$ undergoes thermal decomposition at a lower temperature. Explain your answer.

[2]

The ethanedioate ion is oxidised by acidified $K M n O_{4}$ . $5 C_{2} O_{4}^{2 -} + 2 M n O_{4}^{-} + 16 H^{+} \to 10 C O_{2} + 2 M n^{2 +} + 8 H_{2} O$ An experiment is performed to find the solubility of $M g C_{2} O_{4}$ in water. A $40.0 {cm}^{3}$ sample of saturated aqueous $M g C_{2} O_{4}$ requires $27.05 {cm}^{3}$ of $0.00200 mol {dm}^{- 3}$ acidified $K M n O_{4}$ to oxidise all the $C_{2} O_{4}^{2 -}$ ions. Calculate the solubility, in $mol {dm}^{- 3}$ , of $M g C_{2} O_{4}$ in water. Show your working. $solubility = .............................. mol {dm}^{- 3}$

[3]

a(i)

Phosphine, $: P H_{3}$ , and carbon monoxide, $: C O$ , are monodentate ligands found in some transition element complexes. Define monodentate ligand.

[1]

a(ii)

Define transition element complex.

[1]

a(iii)

Explain why transition elements form complexes.

[1]

b(i)

The formulae of six complexes are given in Table 6.1. The abbreviation en is used for 1,2-diaminoethane. The abbreviation dien is used for the tridentate ligand $H_{2} N C H_{2} C H_{2} N H C H_{2} C H_{2} N H_{2}$ . The dien ligand forms three bonds to the gold ion in $[A u (d i e n) (H_{2} O)_{2} C l]^{2 +}$ and $A u (d i e n) C l_{3}$ . These three bonds all lie in the same plane. The CO ligand coordinates through the carbon atom in $[R h (C O)_{2} C l_{2}]^{+}$ . Table 6.1

formula	isomerism shown	geometry
$[R h (e n)_{2} C l_{2}]^{+}$	yes
$[R h (C O)_{2} C l_{2}]^{+}$	yes
$[A u (d i e n) (H_{2} O)_{2} C l]^{2 +}$
$A u (d i e n) C l_{3}$	no	octahedral
$N i (P H_{3})_{2} C l_{2}$	no
$[N i (H_{2} O)_{2} (N H_{3})_{4}]^{2 +}$	yes

Complete Table 6.1 to state the geometry of the first three complexes. Each complex is either square planar, tetrahedral or octahedral.

[1]

b(ii)

Use complexes $[A u (d i e n) (H_{2} O)_{2} C l]^{2 +}$ and $A u (d i e n) C l_{3}$ to write an equation showing ligand exchange.

[1]

b(iii)

Draw the three-dimensional structure of $A u (d i e n) C l_{3}$ in the box. The dien ligand can be drawn as $N ⌢ N ⌢ N$ .

[1]

b(iv)

Draw the three-dimensional structure of $N i (P H_{3})_{2} C l_{2}$ in the box.

[1]

b(v)

One of the complexes, $[R h (e n)_{2} C l_{2}]^{+}$ or $[R h (C O)_{2} C l_{2}]^{+}$ , can exist in three isomeric forms. Identify this complex and the types of isomerism shown.

[1]

b(vi)

Draw the three-dimensional structures of the two isomers of $[N i (H_{2} O)_{2} (N H_{3})_{4}]^{2 +}$ in the boxes and identify the type of isomerism shown. type of isomerism shown ..............................

[2]

Benzene can be used to make benzoic acid in the two-step process shown in Fig. 7.1. Fig. 7.1

Give the reagents and conditions for step 1 and step 2. step 1 ........................................................................................................................................ step 2 ........................................................................................................................................

[2]

Methylbenzene and benzoic acid each have five different peaks in the carbon ( $^{13} C$ ) NMR spectrum. Table 7.1

hybridisation of the carbon atom	environment of carbon atom	example	chemical shift range / ppm
$s p^{3}$	alkyl	$C H_{3} -$ , $- C H_{2} -$ , $- C H <$ , $> C <$	0–50
$s p^{3}$	next to alkene/arene	$- C - C = C$ , $- C - A r$	25–50
$s p^{3}$	next to carbonyl/carboxyl	$C - C O R$ , $C - O_{2} R$	30–65
$s p^{3}$	next to halogen	$C - X$	30–60
$s p^{3}$	next to oxygen	$C - O$	50–70
$s p^{2}$	alkene or arene	$> C = C <$ , arene ring	110–160
$s p^{2}$	carboxyl	$R - C O O H$ , $R - C O O R$	160–185
$s p^{2}$	carbonyl	$R - C H O$ , $R - C O - R$	190–220
$s p$	nitrile	$R - C \equiv N$	100–125

Use Table 7.1 to complete the two sentences to suggest descriptions of these two spectra. The carbon ( $^{13} C$ ) NMR spectrum of methylbenzene: ● has ................. peak(s) in the chemical shift range of ..................... and ● has ................. peak(s) in the chemical shift range of ..................... . The carbon ( $^{13} C$ ) NMR spectrum of benzoic acid: ● has ................. peak(s) in the chemical shift range of ..................... and ● has ................. peak(s) in the chemical shift range of ..................... .

[2]

c(i)

When treated with $C l_{2}$ under suitable conditions, methylbenzene forms compound J. When treated with $C l_{2}$ under different conditions with different reagents, methylbenzene forms compound K. Suggest and draw structures of compounds J and K in the boxes. The molecular formula of each compound is given. State the reagents and conditions required to form each product. to form compound J .......................................................................................................... to form compound K ..........................................................................................................

[4]

c(ii)

When treated with a chlorine-containing reagent under suitable conditions, benzoic acid forms compound L. When treated with a different chlorine-containing reagent under different conditions, benzoic acid forms compound M. Suggest and draw structures of compounds L and M in the boxes. The molecular formula of each product is given. State the reagents and conditions to form compound M from benzoic acid.

[3]

Lactic acid, $C H_{3} C H (O H) C O O H$ , is the only monomer needed to form the polymer polylactic acid, PLA.

a(i)

Draw a short length of the PLA polymer chain, including a minimum of two monomer residues. The methyl groups may be written as $- C H_{3}$ but all other bonds should be shown fully displayed. Label one repeat unit of polylactic acid on your diagram.

[2]

a(ii)

Give the name of the type of polymerisation involved in the formation of PLA and the name of the functional group that forms between the monomers. type of polymerisation ....................................................................................................... functional group .................................................................................................................

[1]

a(iii)

Predict whether PLA is readily biodegradable. Explain your answer.

[1]

b(i)

The proton ( $^{1} H$ ) NMR spectrum of $C H_{3} C H (O H) C O O H$ in $C D C l_{3}$ is shown in Fig. 8.1. The proton NMR chemical shift ranges are shown in Table 8.1. Table 8.1

environment of proton	example	chemical shift range $δ / ppm$
alkane	$- C H_{3}$ , $- C H_{2} -$ , $> C H -$	0.9–1.7
alkyl next to $C = O$	$C H_{3} - C = O$ , $- C H_{2} - C = O$ , $> C H - C = O$	2.2–3.0
alkyl next to aromatic ring	$C H_{3} - A r$ , $- C H_{2} - A r$ , $> C H - A r$	2.3–3.0
alkyl next to electronegative atom	$C H_{3} - O$ , $- C H_{2} - O$ , $- C H_{2} - C l$	3.2–4.0
attached to alkene	$= C H R$	4.5–6.0
attached to aromatic ring	$H - A r$	6.0–9.0
aldehyde	$H C O R$	9.3–10.5
alcohol	$R O H$	0.5–6.0
phenol	$A r - O H$	4.5–7.0
carboxylic acid	$R C O O H$	9.0–13.0

Use Fig. 8.1 and Table 8.1 to complete Table 8.2. Table 8.2

proton environment	chemical shift ( $δ$ )	name of splitting pattern
$- C O O H$
$⩾ C H$
$- O H$
$- C H_{3}$

[3]

b(ii)

Name the substance responsible for the peak at $δ = 0.0$ .

[1]

b(iii)

Explain why $C D C l_{3}$ is a better solvent than $C H C l_{3}$ for use in proton NMR.

[1]

c(i)

An impure sample of $C H_{3} C H (O H) C O O H$ contains pentan-3-one as the only contaminant. The mixture is analysed using gas/liquid chromatography. The pentan-3-one is found to have a longer retention time than the lactic acid. Explain what is meant by retention time.

[1]

c(ii)

Suggest suitable substances, or types of substances, that could be used as the mobile and stationary phases. mobile phase ..................................................................................................................... stationary phase ................................................................................................................

[1]

c(iii)

Describe how the percentage composition of the mixture can be determined from the gas/liquid chromatogram.

[1]

State the reactants and conditions for two different types of reactions that both produce diethylamine, $C H_{3} C H_{2} N H C H_{2} C H_{3}$ . reaction one .............................................................................................................................. ................................................................................................................................................... reaction two ............................................................................................................................... ...................................................................................................................................................

[4]

Describe the relative basicities of diethylamine, phenylamine and ammonia in aqueous solution. Explain your answer in terms of structure. ............................................... ............................................... ............................................... least basic most basic explanation ............................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................

[3]

Phenylamine reacts with $H N O_{2} (a q)$ at $4^{\circ} C$ to form compound P. Compound P reacts with phenol under alkaline conditions at $4^{\circ} C$ . The product of this reaction is acidified, forming azo compound Q. Draw the structure of compound Q. Circle the azo group on your structure. State one use of an azo compound such as Q. compound Q: An azo compound can be used .............................................................................................. .

[2]

d(i)

$C H_{3} C H_{2} N H C H_{2} C H_{3}$ reacts with ethanoyl chloride, $C H_{3} C O C l$ , to give the amide $N, N$ -diethylethanamide, $C H_{3} C O N (C_{2} H_{5})_{2}$ . An incomplete description of the mechanism of this reaction is shown in Fig. 9.1. Complete the mechanism in Fig. 9.1. You should include: ● all relevant dipoles ( $δ +$ and $δ -$ ) and full electric charges ( $+$ and $-$ ) on the species in box one and in box two ● all relevant lone pairs on the species in box one and in box two ● all relevant curly arrows to show the movement of electron pairs in box one and in box two ● the formula of the second product in box three.

[4]

d(ii)

Name this mechanism.

[1]

Mark scheme

9701/42 · Oct/Nov 2023

Download PDF

1a · 2 marks

1 mark
1 0
1 mark
1 2

1b(i) · 1 mark

1 mark
The line should start at 1  10–5 and decrease to 0.773  10–5 / 7.73  10–6 and be straight for 10 s

1b(ii) · 1 mark

1 mark
its not possible AND the concentrations in the rate law are not known

1c · 1 mark

1 mark
9.24  10–7

1d(i) · 1 mark

1 mark
630

1d(ii) · 1 mark

1 mark
Three halvings taking equal times, these times to agree with their answer to di.

1e(i) · 1 mark

1 mark
CH3COH=CH2 + I2 → CH3C+(OH)CH2I + I–

1e(ii) · 1 mark

1 mark
step 1 AND has (both) substances in rate law.

1e(iii) · 1 mark

1 mark
CH3C+OHCH3 and CH3COCH3 OR CH3C+(OH)CH3 and CH3C(OH)=CH2 OR CH3C+(OH)CH2I and CH3COCH2I

2a · 1 mark

1 mark
resists pH change when small amount of acid or alkali is added

2b(i) · 1 mark

1 mark
C6H5COOH + NaOH → C6H5COO–Na+ + H2O

2b(ii) · 1 mark

1 mark
C6H5COO–Na+ + HNO3 → C6H5COOH + NaNO3

2c · 3 marks

1 mark
[H+] = 7.08  10–5
1 mark
[C6H5COOH] = 8.20  10–3
1 mark
[C6H5COO–Na+] = 7.31  10–3

2d · 2 marks

1 mark
neutralisation is exothermic
1 mark
All of the C6H5COOH has reacted AND excess KOH

2e(i) · 2 marks

1 mark
If [X] = [Mg2+] = [Mg(C6H5COO–)2] 4X3 = 1.76  10–7 so X = 3.53  10–3
1 mark
0.940 g dm–3

2e(ii) · 1 mark

1 mark
lower than AND common ion effect

3a(i) · 1 mark

1 mark
hydrogen, delivery system, H+, platinum,

3a(ii) · 1 mark

1 mark
iron . . . . . hydrogen . . . . . iron

3b(i) · 1 mark

1 mark
(for specified V2+, V3+ or VO2+) Eo is more positive than / above –0.44 AND more negative than / below 0.77 V

3b(ii) · 1 mark

1 mark
V and VO2+

3b(iii) · 1 mark

1 mark
V + Fe2+ → V2+ + Fe OR VO2+ + 2H+ + Fe2+ → VO2+ + H2O + Fe3+

3c(i) · 2 marks

1 mark
Nernst: E = 0.77 + (0.059 / z)log[ox] / [red]
1 mark
0.947

3c(ii) · 1 mark

1 mark
2Fe3+ + Cl– + 2OH– → 2Fe2+ + ClO– + H2O

3d · 3 marks

1 mark
Eocell = 1.33 V
1 mark
Go = –nEocellF
1 mark
–257

3e · 3 marks

1 mark
0.64  17  60 = 653 / 652.8 Coulombs
1 mark
652.8 ÷ 1.6x10–19 = 4.08  1021 (number of electrons) 4.08  1021 ÷ 2 = 2.04  1021 (number of atoms Fe)
1 mark
0.185 ÷ 55.8 = 3.31  10–3 (number of moles Fe atoms 2.04  1021 ÷ 3.31  10–3 = L = 6.153  1023

3f(i) · 3 marks

1 mark
S = –179
1 mark
G = H –TS
1 mark
–74.7

3f(ii) · 1 mark

1 mark
less AND G becomes more positive

4a · 1 mark

1 mark
equilibrium constant for the formation of a complex in a solvent / from its constituents

4b · 1 mark

1 mark
+2 AND + 3

4c · 1 mark

1 mark
Six

4d · 1 mark

1 mark
[Fe(EDTA)]– AND largest Kstab

4e · 2 marks

1 mark
[[CuEDTA]2–] ÷ ([[Cu(H2O)6]2+]  [EDTA2–]) = 6.311019
1 mark
0.095

4f · 2 marks

1 mark
different E OR different energy gap between d-orbitals
1 mark
absorption of different wavelength OR absorption of different frequency

5a · 1 mark

1 mark
MgC2O4 → MgO + CO2 + CO

5b · 2 marks

1 mark
magnesium ethanedioate decomposes at lower T because Mg2+ has smaller radius than Ca2+
1 mark
so anion is more polarised by Mg2+

5c · 3 marks

1 mark
(27.05 ÷ 1000)  0.02 = 5.41  10–5 moles MnO4–
1 mark
5.41  10–5  5/2 = 1.3525  10–4 moles C2O42–
1 mark
0.00338 mol dm–3

6a(i) · 1 mark

1 mark
donates one lp to metal atom or ion

6a(ii) · 1 mark

1 mark
metal atom or ion bonded to one or more ligands

6a(iii) · 1 mark

1 mark
has vacant d-orbitals which are energetically accessible

6b(i) · 1 mark

1 mark
octahedral square planar octahedral

6b(ii) · 1 mark

1 mark
[Au(dien)(H2O)2Cl]2+ + 2Cl– → [Au(dien)Cl 3] + 2H2O OR [Au(dien)Cl 3] + 2H2O → [Au(dien)(H2O)2Cl]2+ + 2Cl–

6b(iii) · 1 mark

1 mark
diagram of Au complex with dien ligand and three Cl ligands

6b(iv) · 1 mark

1 mark
3D tetrahedral diagram showing Ni bonded to two PH3 and two Cl ligands

6b(v) · 1 mark

1 mark
[Rh(en)2Cl2]+ AND optical AND cis / trans OR geometric

6b(vi) · 2 marks

1 mark
diagram of cis and trans isomers of [Ni(NH3)4(H2O)2]2+
1 mark
cis/trans OR geometric

7a · 2 marks

1 mark
CH3Cl + AlCl3
1 mark
hot alkaline) MnO4–

7b · 2 marks

1 mark
4, 110-160, 1, 25-50 either order
1 mark
4, 110-160, 1, 160-185 either order

7c(i) · 4 marks

1 mark
either 2-chlorotoluene or 4-chlorotoluene structure for J or K
1 mark
(chloromethyl)benzene structure for J or K
1 mark
for the ring substituted product – AlCl3
1 mark
for the side-chain substituted product – uv

7c(ii) · 3 marks

1 mark
Structure of 2-chlorobenzoic acid (L)
1 mark
Structure of benzoyl chloride (M)
1 mark
PCl3 + heat OR SOCl2 OR PCl5

8a(i) · 2 marks

1 mark
diagram has trailing bonds, two or more monomer residues AND either repeat unit correct OR ester linkage correct
1 mark
diagram fully correct

8a(ii) · 1 mark

1 mark
condensation AND ester

8a(iii) · 1 mark

1 mark
it is biodegradable because it can hydrolyse

8b(i) · 3 marks

1 mark
d values: 12, 4.4
1 mark
5.0, 1.6
1 mark
splitting patterns: singlet, quartet / quadruplet, singlet, doublet

8b(ii) · 1 mark

1 mark
TMS / tetramethylsilane

8b(iii) · 1 mark

1 mark
CDCl3 will not give an absorption / peak OR CHCl3 will give an absorption / peak

8c(i) · 1 mark

1 mark
time between injection and detection

8c(ii) · 1 mark

1 mark
an unreactive gas AND a non-polar liquid

8c(iii) · 1 mark

1 mark
area of peak divided by total area of all peaks  100%

9a · 4 marks

1 mark
chloroethane and ethylamine
1 mark
heat, pressure, ethanol
1 mark
N-ethyl ethanamide CH3CONHC2H5
1 mark
LiAlH4

9b · 3 marks

1 mark
phenylamine, ammonia, diethylamine
1 mark
Two bullet points from: - Availability of lone pair on N to receive H+ - phenylamine – LP, delocalised / overlaps into ring - diethylamine – ethyl are electron donating
1 mark
Three bullet points from: - Availability of lone pair on N to receive H+ - phenylamine – LP, delocalised / overlaps into ring - diethylamine – ethyl are electron donating

9c · 2 marks

1 mark
Structure of azo compound Q (4-(phenyldiazenyl)phenol / 4-hydroxydiazoarene structure)
1 mark
N2 or N=N circled AND dye / colouring

9d(i) · 4 marks

1 mark
box one: 1 dipole on C=O, 2 LP on N of amine
1 mark
box one: 3 CA from N of amine to C of acyl chloride, 4 CA from = to O of acyl chloride
1 mark
box two: 5 + on what was N of amine and nowhere else, 6 – on what was O of acyl chloride and nowhere else, 7 LP on what was O of acyl chloride
1 mark
box two: 8 CA from N-H bond to what was N of amine, 9 CA from C-Cl bond to what was Cl of acyl chloride, 10 CA from (LP on) O to reform C=O AND box three: 11 HCl

9d(ii) · 1 mark

1 mark
Addition-elimination

Questions

1
Question 110 marks
Mark scheme ›
2
Question 211 marks
Mark scheme ›
3
Question 318 marks
Mark scheme ›
4
Question 48 marks
Mark scheme ›
5
Question 56 marks
Mark scheme ›
6
Question 610 marks
Mark scheme ›
7
Question 711 marks
Mark scheme ›
8
Question 812 marks
Mark scheme ›
9
Question 914 marks
Mark scheme ›

A Level Chemistry 9701 Paper 42, Oct/Nov 2023

Solve it on ExamPal

Practise

Exam

Question paper

Mark scheme

1a · 2 marks

1b(i) · 1 mark

1b(ii) · 1 mark

1c · 1 mark

1d(i) · 1 mark

1d(ii) · 1 mark

1e(i) · 1 mark

1e(ii) · 1 mark

1e(iii) · 1 mark

2a · 1 mark

2b(i) · 1 mark

2b(ii) · 1 mark

2c · 3 marks

2d · 2 marks

2e(i) · 2 marks

2e(ii) · 1 mark

3a(i) · 1 mark

3a(ii) · 1 mark

3b(i) · 1 mark

3b(ii) · 1 mark

3b(iii) · 1 mark

3c(i) · 2 marks

3c(ii) · 1 mark

3d · 3 marks

3e · 3 marks

3f(i) · 3 marks

3f(ii) · 1 mark

4a · 1 mark

4b · 1 mark

4c · 1 mark

4d · 1 mark

4e · 2 marks

4f · 2 marks

5a · 1 mark

5b · 2 marks

5c · 3 marks

6a(i) · 1 mark

6a(ii) · 1 mark

6a(iii) · 1 mark

6b(i) · 1 mark

6b(ii) · 1 mark

6b(iii) · 1 mark

6b(iv) · 1 mark

6b(v) · 1 mark

6b(vi) · 2 marks

7a · 2 marks

7b · 2 marks

7c(i) · 4 marks

7c(ii) · 3 marks

8a(i) · 2 marks

8a(ii) · 1 mark

8a(iii) · 1 mark

8b(i) · 3 marks

8b(ii) · 1 mark

8b(iii) · 1 mark

8c(i) · 1 mark

8c(ii) · 1 mark

8c(iii) · 1 mark

9a · 4 marks

9b · 3 marks

9c · 2 marks

9d(i) · 4 marks

9d(ii) · 1 mark

Questions

More 9701 papers

Other papers from Oct/Nov 2023