Find an IGCSE Chemistry tutor

The course code matters when choosing practice questions. These are separate Chemistry qualifications; a Science Double Award course needs its own specification. Check the code on a school document or exam paper and confirm it with the school or exam centre.

The Cambridge details below apply to exams in 2026–2028. Pearson also offers a modular International GCSE, but that route is only available to schools outside the UK. Its unit papers should not be treated as the paper sequence for the linear 4CH1 course.

A request such as ‘help with bonding’ becomes more useful when it identifies what the learner cannot yet do. Use a short task from the correct syllabus to choose the starting point; the examples below are possible lesson goals, not a fixed programme.

This constructed practice question illustrates two calculation routes. 2.4 g of magnesium reacts completely with excess oxygen to form magnesium oxide. What mass of oxide forms? Use relative atomic masses Mg = 24 and O = 16.

The balanced equation is 2Mg + O₂ → 2MgO. There are two magnesium atoms and two oxygen atoms on each side. Keep MgO’s formula unchanged when balancing.

A proportional method for Cambridge Core: the equation gives a mass ratio of 48 g magnesium to 80 g magnesium oxide: 2 × 24 compared with 2 × (24 + 16). Our 2.4 g is one twentieth of 48 g, so it forms one twentieth of 80 g: 4.0 g of magnesium oxide. This uses reacting-mass proportions without moles.

The mole method for Cambridge Extended and Pearson 4CH1: amount of magnesium = mass ÷ molar mass = 2.4 ÷ 24 = 0.100 mol. The equation’s Mg:MgO ratio is 2:2, or 1:1, so 0.100 mol of MgO forms. Its molar mass is 40 g/mol; mass = 0.100 × 40 = 4.0 g.

An answer of 2.4 g would overlook the oxygen joining the magnesium. The product contains the original 2.4 g of magnesium plus 1.6 g of oxygen; mass is conserved when both reactants are counted. A useful next check is to change the starting magnesium mass and explain the method without copying the worked solution.

Cambridge places mole calculations in the Supplement content studied for Extended assessment. Core learners can secure the proportional reasoning first. For either method, understanding the equation matters more than remembering a sequence of calculator buttons.

Consider a constructed data exercise about marble chips, treated here as pure calcium carbonate, reacting with hydrochloric acid to release carbon dioxide. Compare equal masses of large and small chips using the same acid volume and concentration, with acid in excess, at the same temperature. Assume complete reaction and collection of the gas in the same apparatus. This is an exercise in interpreting results.

Suppose the small chips give 32 cm³ of gas after 30 seconds, while the large chips give 18 cm³. Both eventually produce 50 cm³: the small chips reach that plateau at 90 seconds and the large chips at 150 seconds. The chip size is the variable changed; gas volume over time is measured. Holding the other conditions constant makes chip size a fair comparison.

‘Small chips make more gas’ is incomplete: they have made more gas at 30 seconds, but the final volume is the same. A better description is: ‘The small chips have a greater average rate over the first 30 seconds and reach the final gas volume sooner. Both produce 50 cm³ overall.’ The graph for the small chips rises further over the first 30 seconds and levels off sooner, at the same height.

For the collision explanation used in Cambridge Extended and Pearson 4CH1, smaller chips provide more exposed surface area for the same mass. Acid particles can collide with that surface more frequently, increasing successful collisions per second. Breaking up the chips does not increase the amount of calcium carbonate, so it does not increase the final gas yield under these conditions.

This also shows the difference between describe and explain: a description reports the pattern; an explanation gives the chemical reason. Cambridge Core includes interpreting rate data, while collision theory is Supplement content. A tutor can use the learner’s answer to decide which part needs work.

A low total score does not show whether the next lesson should tackle knowledge, calculations or written answers. Here is a practical way to agree a focus with a tutor. It also works with a small set of homework questions when there is no mock paper.

For one defined gap, such as reacting masses, agree a short block of work and a review point. For difficulties across several topics, consider a regular lesson with independent practice between meetings. Near an exam, use the remaining time to prioritise specific errors and the papers still to come. These are planning options, not a prescribed lesson frequency.

Look for a tutor who can discuss your exact course and explain how they would check the learner’s understanding. In the free introductory meeting, bring one difficult question and describe what happens when the learner gets stuck. Agree a first goal, the practice expected and how you will judge progress. The introduction is a conversation about fit and arrangements, rather than a full free teaching lesson.

Useful signs of progress are concrete: balancing an unfamiliar equation without help, choosing the correct mass ratio, or explaining a graph using its data. Review those alongside the learner’s confidence. If the same error keeps returning, revisit the prerequisite skill or reduce the number of steps being practised at once.

For a learner who needs more processing time, clearer language or a quieter pace, describe that need directly. You might request one calculation step per line, a labelled particle diagram or time to rehearse an explanation aloud. Discuss the approach with the individual tutor before agreeing lessons.

If the next goal is AS or A-level Chemistry, say so in the first discussion. Cambridge presents IGCSE Chemistry as a foundation for further study; check the chosen sixth form’s entry requirements separately.