AQA A LEVEL CHEMISTRY 2022 PREDICTED PAPER 3 

A-Level Chemistry AQA

Paper 3

Predicted Paper 2022

Name ………………

Date …………………

2 hours allowed

You should spend around 70 minutes on section A and 50 minutes on section B.

Question Possible marks Marks gained

1 7

2 15

3 13

4 14

5 11

Section B 30

Total 90

The Advanced Information from the exam board gives us a broad overview of what is covered in the exam. The information was given in ranked order, and this has been reflected in the mark allocation and topics on this paper.

There are questions in this paper that cover topics that are not listed by the exam board. These are in the multiple-choice section and a few marks in low tariff and synoptic questions – this is exactly what you should expect in the exam.

Section A

01 X is a metallic element.

An electrochemical cell was set up consisting of an X2+(aq)|X(s) half-cell (Eø= 0.34 V) and an Ag+(aq)|Ag(s) half cell (Eø= +0.80V).

I. Write an equation for the reaction that would take place if the electrode of this cell were connected by a wire.

[1 mark]

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II. When the current was allowed to pass for a period of time, the Ag electrode gained 1.30 g in mass and the electrode made of metal X lost 0.38 g in mass.

Identify the metal X.

[4 marks]

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III. State the charge carriers that transfer current through:

[2 marks]

The solution:

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The wire:

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02 Consider the following reaction:

02.1

I. Write the IUPAC name of the compound X

[1 mark]

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II. Outline the mechanism for the above reaction.

[3 marks]

III. What type of mechanism occurs in part (II)?

[1 mark]

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02.2 When trichloromethane reacts with chlorine, the organic product is tetrachloromethane.

I. Give one essential condition for this reaction and name the type of mechanism involved.

[2 marks]

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II. The reaction takes place in a series of steps.

Write equations for the following steps in the mechanism for the reaction of chlorine with trichloromethane.

[4 marks]

Initial step:

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First propagation step:

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Second propagation step:

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Termination step producing tetrachloromethane:

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02.3 Chlorine radicals in the stratosphere act as a catalyst for ozone depletion.

The equations below represent the part of the possible reaction mechanism for the ozone depletion.

I. Complete the following equations:

Cl + O3    ……………… + ……………

ClO + …………  …………… + O2

[3 marks]

II. Write an equation for the overall reaction in part 02.3 (I).

[1 mark]

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03 The data in the following table were obtained in five experiments about the rate of the reaction between chlorine dioxide ClO2 and fluorine F2 at a constant temperature.

Experiment Initial concentration of

ClO2 (mol dm-3) Initial concentration of F2

(mol dm-3) Initial rate

01 0.17 0.02 2.6×10-3

02 0.68 0.02 10.4×10-3

03 0.17 To be calculated 18.2×10-3

04 0.68 0.06 31.2×10-3

05 0.51 0.08 To be calculated

03.1 Deduce the order of the reaction with respect to ClO2.

[1 mark]

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03.2 Deduce the order of the reaction with respect to F2.

[1 mark]

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03.3 Write the overall rate equation for this reaction.

[1 mark]

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03.4 Calculate the rate constant K for this reaction, including the units of K.

[2 marks]

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03.5 Use the data in the table to calculate the initial rate in experiment 05, including the units.

[2 marks]

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03.6 Use the data in the table to calculate the [F2] in experiment 03.

[1 mark]

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03.7 03.7

I. The mechanism of the reaction between ClO2 and F2 has two steps. Write the equations for the two steps of this mechanism.

[2 marks]

Step one:

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Step two:

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II. Explain the meaning of the term “rate determining step”.

[1 mark]

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III. State and explain which of the two steps is the rate determining step of this reaction.

[2 marks]