Maths questions
Don’t 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’s 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 to do with 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’t 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 ±«Óătv Sounds.
Brush up on the maths you need for your exam - percentages, averages and converting units.
Sample question 1 - Foundation
Question
Magnesium reacts with oxygen:
2Mg + O2 → 2MgO
Calculate the maximum mass of magnesium oxide that can be formed from 4.86 g of magnesium.
(Relative atomic mass of Mg = 24.3; relative formula mass of MgO = 40.3)
[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.
- 24.3 g of Mg produces 40.3 g of MgO [1]
- 4.86 g of Mg produces 40.3 Ă— 4.86/24.3 = 8.06 g [1]
Sample question 2 - Higher
Question
Element X reacts with oxygen, O2. There is one product, X oxide.
12.7 g of X reacts with 3.20 g of oxygen to make 15.9 g of X oxide.
a) Calculate the number of moles of X, oxygen and X oxide involved in the reaction.
(The relative atomic mass of X is 63.5; the relative formula mass of oxygen, O2, is 32.0 and of X oxide is 79.5.)
[3 marks]
b) Use your answers to write the balanced symbol equation for the reaction between X and oxygen to make X oxide.
[2 marks]
OCR Gateway Science, GCE Chemistry, Paper J248, 2016 - Higher.
a)
- moles of X = 12.7/63.5 = 0.2 mol [1]
- moles of O2 = 3.20/32.0 = 0.1 mol [1]
- moles of X oxide = 15.9/79.5 = 0.2 mol [1]
b)
- 2X + O2 → 2XO
- correct formulae [1]
- balancing of correct formulae [1]
You must get the formulae right first to gain the second mark.