Maths questions
Don鈥檛 forget to take a ruler and calculator into the exam.
Maths questions often start with the command words like Calculate, Determine, Estimate and Measure. They will then include blank space for you to show your working.
When an answer to a maths question is marked:
- full marks are given for the right answer (but it鈥檚 wise to show your working so you can check your answer)
- marks are given for working, including substitution and rearrangement
- errors carried forward are taken into account
If a later answer depends on an earlier answer, and you get the earlier one wrong, you could still get full marks in the later answer if your working is correct.
If your answer has many decimal places or figures, make sure you give it to an appropriate number of decimal places or significant figures. You may be asked to give units. This may earn you an additional mark, so don鈥檛 forget to check whether you need to do this.
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
You may be given a grid with axes 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
- make sensible scales so that the plotted points cover at least 50% of the area of the graph
- label the axes with their quantity and unit, eg time (s)
Sample question 1 - Foundation
Question
Carbon dioxide is one of several greenhouse gases.
It is made by the combustion of fossil fuels such as coal, gas and oil.
Look at the table. It shows the amount of carbon dioxide produced, from burning fossil fuels, in a large city in the years 2010 and 2016.
| Source of carbon dioxide | Carbon dioxide produced (tonnes) in 2010 | Carbon dioxide produced (tonnes) in 2016 | Percentage increase (%) |
| Homes | 500 000 | 600 000 | 20 |
| Factories and industry | 500 000 | 750 000 | 50 |
| Transport | 1 000 000 | 1 000 000 | 0 |
| Electricity generation | 750 000 | 900 000 |
| Source of carbon dioxide | Homes |
|---|---|
| Carbon dioxide produced (tonnes) in 2010 | 500 000 |
| Carbon dioxide produced (tonnes) in 2016 | 600 000 |
| Percentage increase (%) | 20 |
| Source of carbon dioxide | Factories and industry |
|---|---|
| Carbon dioxide produced (tonnes) in 2010 | 500 000 |
| Carbon dioxide produced (tonnes) in 2016 | 750 000 |
| Percentage increase (%) | 50 |
| Source of carbon dioxide | Transport |
|---|---|
| Carbon dioxide produced (tonnes) in 2010 | 1 000 000 |
| Carbon dioxide produced (tonnes) in 2016 | 1 000 000 |
| Percentage increase (%) | 0 |
| Source of carbon dioxide | Electricity generation |
|---|---|
| Carbon dioxide produced (tonnes) in 2010 | 750 000 |
| Carbon dioxide produced (tonnes) in 2016 | 900 000 |
| Percentage increase (%) |
(a) Look at the row for electricity generation.
Calculate the percentage increase in carbon dioxide produced. [2 marks]
(b) Analyse the data in the table.
What is the ratio of carbon dioxide produced from Homes to Electricity generation for 2016? [2 marks]
OCR Gateway Science, GCE Chemistry, Paper J248, 2016.
(a)
- (150,000/750,000) 脳 100 [1])
- = 20% [1]
(b)
- 600,000 : 900,000 [1]
- = 2 : 3 [1]
Sample question 2 - Higher
Question
Nitrogen reacts with oxygen in car engines to produce oxides of nitrogen.
One of these oxides of nitrogen is nitrogen dioxide:
N2 + 2O2 鈫 2NO2
Calculate the maximum mass of nitrogen dioxide that can be formed from 6.0 dm3 of nitrogen and an excess of oxygen.
Assume that one mole of gas occupies a volume of 24 dm3 at room temperature and pressure.
(Relative formula mass of NO2 = 46.0)
[4 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.
number of moles of N2 = 6.0/24 [1]
= 0.25 mol [1]
number of moles of NO2 = 2 脳 0.25 mol = 0.50 mol [1]
mass of NO2 = 0.50 脳 46.0 = 23.0 g [1]