Sample exam questions - energy changes - AQAMaths questions

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.

Part ofChemistry (Single Science)Energy changes

Maths questions

Don't forget to take a ruler and calculator into the exam.

Maths questions often start with the command word 'calculate'. You need to use numbers given in the question to work out the answer.

When an answer to a maths question is marked:

  • full marks are given for the right answer
  • marks may be given for working, including substitution and rearrangement
  • errors carried forward are worked through to give credit for later working

Learn maths skills with Dr Alex Lathbridge

Brush up on the maths you need for your exam - percentages, averages and converting units.

Make sure you give answers to a suitable number of significant figures.

Maths questions might ask you to plot or complete a graph or table. When you draw a graph, make sure you:

  • plot each point accurately
  • draw a best fit straight line or curve, where appropriate

You may be given a grid with axes labelled and scales already given. Sometimes you may be given an empty grid for you to supply your own axes. When you do this:

  • put the independent variable on the x-axis and the dependent variable on the y-axis
  • choose even scales and make sure that the points cover at least half the given grid
  • label the axes with their quantity and unit, eg time (s)

Sample question 1 - Foundation

Question

The overall energy change is 386 kJ.

What percentage of 1370 kJ is this? Give your answer to two significant figures.

[2 marks]

This question is AQA material which is reproduced by permission of AQA.

Sample question 2 - Foundation

Question

A student investigated the energy released during the combustion of ethanol. Her results are shown in the table below.

Table 1 shows his results.

Table 1

Experiment 1Experiment 2Experiment 3
Initial temperature19°C21°C20°C
Final temperature39°C42°C39°C
Initial temperature
Experiment 119°C
Experiment 221°C
Experiment 320°C
Final temperature
Experiment 139°C
Experiment 242°C
Experiment 339°C

Calculate the mean temperature difference in the water.

[2 marks]

This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.

Sample question 3 - Higher

Question

Combustion is an exothermic reaction. Calculate the overall energy change for the complete combustion of one mole of methane in oxygen.

Molecular structure of methane oxygen combustion
BondBond energy in kJ/mol
C–H413
O=O498
C=O805
O–H464
BondC–H
Bond energy in kJ/mol413
BondO=O
Bond energy in kJ/mol498
BondC=O
Bond energy in kJ/mol805
BondO–H
Bond energy in kJ/mol464

[3 marks]

This question is AQA material which is reproduced by permission of AQA.

Sample question 4 - Higher

Question

A student investigated the reactivity of different metals by reacting them with dilute hydrochloric acid. The results are shown in the table below.

MetalTest 1 temp riseTest 2 temp riseTest 3 temp rise
Calcium17.8°C16.9°C17.5°C
Iron6.2°C6.0°C6.1°C
MetalCalcium
Test 1 temp rise17.8°C
Test 2 temp rise16.9°C
Test 3 temp rise17.5°C
MetalIron
Test 1 temp rise6.2°C
Test 2 temp rise6.0°C
Test 3 temp rise6.1°C

Calculate the mean temperature rise for calcium.

[1 mark]

This question is AQA material which is reproduced by permission of AQA.