Maths questions
Don鈥檛 forget to take a ruler and calculator into the exam.
Maths questions often start with 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
'Errors carried forward' is what happens 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 but you use the incorrect earlier answer.
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)
Learn maths skills with Dr Alex Lathbridge
Listen to the full series on 麻豆官网首页入口 Sounds.
Brush up on the maths you need for your exam - percentages, averages and converting units.
Sample question 1 - Foundation
Question
The formula for rust can be given as: Fe2O3.3H2O
Calculate the percentage by mass of iron in rust. Give your answer to two decimal places. [2 marks]
(Relative atomic mass of iron = 55.8 and relative formula mass of rust = 213.6)
OCR Gateway Science, GCE Chemistry, Paper J248, 2016.
% of Fe = \(\frac{(2\ X\ 55.8)}{213.6}\) x 100 [1]
= 52.25% [1]
Sample question 2 - Foundation
Question
It takes 46.8 MJ of energy to extract 1 kg of aluminium from its ore. It only takes 5% of this to recycle 1 kg of aluminium.
Calculate the amount of energy used when recycling 1 kg of aluminium. [1 mark]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Amount of energy used = 46.8 脳 5/100 = 2.34 MJ [1]
Sample question 3 - Higher
Question
Rusting can be modelled using this balanced symbol equation:
4Fe + 6H2O + 3O2 鈫 2Fe2O3.3H2O
A 750 g iron bar is left outside in the rain. All of the iron turns to rust, Fe2O3.3H2O.
The rust forms at a rate of 50 g per day.
Calculate how long it will take for the iron bar to turn completely to rust. Give your answer to the nearest day. [6 marks]
(Relative atomic mass of iron = 55.8 and relative formula mass of rust = 213.6)
OCR Gateway Science, GCE Chemistry, Paper J248, 2016 - Higher.
moles of iron = 750/55.8 = 13.44 mol [1]
mole ratio (rust/iron) = 2/4 = 0.5 [1]
moles of rust = 13.44 脳 0.5 = 6.72 mol [1]
mass of rust = 6.72 脳 213.6 = 1435.4 g [1]
days to rust = 1435.4/50 [1]
= 29 days [1]
Sample question 4 - Higher
Question
Aluminium is extracted from purified aluminium oxide using electrolysis.
Write a balanced half equation for the reaction that happens at the cathode, and explain whether aluminium ions are oxidised or reduced. [3 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.
Al3+ + 3e- 鈫 Al
- correct formulae [1]
- correct formulae correctly balanced [1]
- aluminium ions are reduced because they gain electrons [1]