Who this is for: Cambridge IGCSE Chemistry (0620) students using Stoichiometry topical past paper questions who mix up formulae, Mr and mole conversions in the same calculation chain.
What query it owns: how to use Stoichiometry topical past paper questions strategically in Cambridge IGCSE Chemistry.
Why this is safe: this page owns the strategic topical-practice angle for the Stoichiometry unit, while Tutopiya’s Stoichiometry topical past paper questions page owns the actual question bank.

Stoichiometry topical past paper questions group real Cambridge stems on formulae, relative masses, moles, reacting masses and gas volumes. Many students lose marks not from weak maths but from breaking the calculation chain at the wrong step. This guide shows how to diagnose which area failed, repair it, and re-test before doing more volume.

Key takeaways

• Label each wrong answer: formula, Mr, mole conversion or molar ratio — not just “calculation error”.
• Write the balanced equation before any reacting-mass or gas-volume work.
• Check whether the substance is diatomic (H₂, O₂, N₂, Cl₂) before calculating Mr.
• Repair with the matching subtopic quiz before more topical questions.
• The topical bank has no quiz — use subtopic quizzes below to confirm fixes.

What are Stoichiometry topical past paper questions?

Stoichiometry topical past paper questions are curated Cambridge IGCSE Chemistry (0620) exam questions filtered to formulae, relative masses and mole calculations. Tutopiya’s Stoichiometry topical past paper questions resource lets you practise one subtopic at a time with authentic command words.

A strategic revision loop — step by step

1. Pick one subtopic — formulae or mole calculations — for a diagnostic mini-set.
2. Attempt 3–5 topical questions without notes; tag where your chain broke.
3. Mark and tag errors — wrong formula? forgot 24 dm³? skipped molar ratio?
4. Repair via subtopic page + quiz for that area only.
5. Re-test the same stem type in the topical bank before mixing subtopics.

Which Stoichiometry area is actually weak?

If you keep losing marks on…	Return to this subtopic	Quiz to confirm
Writing formulae, empirical formula, ion counting	Formulae	Formulae quiz
Ar, Mr, reacting masses, % composition	Relative Masses of Atoms and Molecules	Relative Masses quiz
Moles, Avogadro constant, gas volume at rtp	The Mole and the Avogadro Constant	Mole quiz

Stoichiometry in past-paper wording: command words that matter

Command word	What the question wants	Typical stoichiometry stem
Calculate	Full numerical working shown	”Calculate the mass of CO₂ produced.”
Determine	Work out from experimental data	”Determine the empirical formula.”
Deduce	Infer formula or ratio	”Deduce the molecular formula.”
Show that	Prove a given value	”Show that 0.5 mol of NaOH has a mass of 20 g.”
How many moles	Mole conversion step	”How many moles in 88 g of CO₂?”

Worked exam-style stems

1. “Calculate the mass of carbon dioxide produced when 12 g of carbon burns completely.” C + O₂ → CO₂. 12 g C = 1 mol → 1 mol CO₂ = 44 g. Reward: balanced equation + molar ratio.
2. “A compound has Mr = 90 and contains 40% carbon. Calculate the number of carbon atoms in one molecule.” C mass per molecule = 0.40 × 90 = 36 g → 36/12 = 3 carbon atoms. Reward: % applied to Mr correctly.
3. “Calculate the volume of hydrogen formed at rtp when 0.2 mol of zinc reacts with excess acid.” Zn + 2HCl → ZnCl₂ + H₂. 0.2 mol Zn → 0.2 mol H₂ → 0.2 × 24 = 4.8 dm³. Reward: 1:1 ratio + gas volume.

Work the full set on the Stoichiometry topical past paper questions after repairing weak subtopics.

Common mistakes students make

• Starting calculations without a balanced equation.
• Using atomic mass of O instead of Mr of O₂ for oxygen gas.
• Applying 24 dm³ to liquids or solids.
• Wrong empirical formula because mole ratios were not simplified.
• Doing topical volume without subtopic repair loops.

When you need more support

If Stoichiometry topical questions keep exposing the same gap after two repair cycles, book a Cambridge IGCSE Chemistry tutor. The Cambridge IGCSE Chemistry resource hub links all Stoichiometry resources.

Frequently asked questions

Do Stoichiometry topical past paper questions have a quiz? No — the topical bank is Learn-only. Use the Formulae quiz or Mole quiz to confirm fixes.

Should I revise formulae or moles first? Start with Formulae and Relative Masses — mole questions fail when Mr is wrong.

How many topical questions should I do per session? Three to five per error tag, then repair — not twenty mixed calculations without marking.

Where does gas volume fit in topical practice? Gas volume stems need The Mole and the Avogadro Constant — practise n = V/24 before mixed topical sets.

Ready to master Stoichiometry topical practice?

Open the Stoichiometry topical past paper questions, then book a free trial with a Cambridge IGCSE Chemistry specialist.

Ready to Excel in Your Studies?

Get personalised help from Tutopiya's expert tutors. Whether it's IGCSE, IB, A-Levels, or any other curriculum — we match you with the perfect tutor and your first session is free.

Book Your Free Trial