AQA Alevel Chemistry 2022 Paper 3

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A-level
CHEMISTRY
Paper 3

Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Booklet, provided as an insert (enclosed)
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate. 1
2
Instructions
3
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page. 4
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write outside Section B
the box around each page or on blank pages.
• If you need extra space for your answer(s), use the lined pages at the end of TOTAL
this book. Write the question number against your answer(s).
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not
want to be marked.

Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 90.

Advice
• You are advised to spend 70 minutes on Section A and 50 minutes on Section B.




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There are no questions printed on this page box




DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED




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Section A box


Answer all questions in this section.


0 1 A value for enthalpy of solution can be determined in two ways:

• from a cycle, using lattice enthalpy and enthalpies of hydration
• from the results of a calorimetry experiment.

0 1 . 1 Define the term enthalpy of lattice dissociation.
[2 marks]




0 1 . 2 The enthalpy of solution for ammonium nitrate is the enthalpy change for the reaction
shown.

NH4NO3(s) + aq → NH4+(aq) + NO3−(aq) ∆H = +26 kJ mol−1

Table 1


NH4+(g) NO3−(g)

Enthalpy of hydration hydH / kJ mol 1 −307 −314


Draw a suitably labelled cycle and use it, with data from Table 1, to calculate the
enthalpy of lattice dissociation for ammonium nitrate.
[3 marks]




Enthalpy of lattice dissociation kJ mol−1


Turn over ►


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0 1 . 3 A student does an experiment to determine a value for the enthalpy of solution for box

ammonium nitrate.

The student uses this method.

• Measure 25.0 cm3 of distilled water in a measuring cylinder.
• Pour the water into a beaker.
• Record the temperature of the water in the beaker.
• Add 4.00 g of solid NH4NO3 to the water in the beaker.
• Stir the solution and record the lowest temperature reached.

Table 2 shows the student’s results.

Table 2

Initial temperature / °C 20.2

Lowest temperature / °C 12.2

Calculate the enthalpy of solution, in kJ mol−1, for ammonium nitrate in this
experiment.

Assume that the specific heat capacity of the solution, c = 4.18 J K−1 g−1

Assume that the density of the solution = 1.00 g cm−3
[3 marks]




Enthalpy of solution kJ mol−1




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