Stoichiometry: past paper questions

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• Question 9May/June 2026, paper 11Multiple choice1 mark

  What is the formula of potassium oxide?

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• Question 8Oct/Nov 2025, paper 11Multiple choice1 mark

  Carbon dioxide gas reacts with aqueous calcium hydroxide to form calcium carbonate. Which equation represents this reaction?

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• Question 7Oct/Nov 2024, paper 11Multiple choice1 mark

  Metal X is in Group II of the Periodic Table. X is reacted separately with dilute sulfuric acid and with oxygen. Which row identifies the products of each reaction?

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• Question 7Oct/Nov 2023, paper 11Multiple choice1 mark

  Which equations are balanced?

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• Question 10May/June 2026, paper 11Multiple choice1 mark

  Which compound contains the greatest number of atoms in its formula?

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• Question 9Oct/Nov 2025, paper 11Multiple choice1 mark

  The equation for the combustion of magnesium is shown. $$2\text{Mg}+{\text{O}}_2\to 2\text{MgO}$$ Which mass of magnesium oxide will be formed from the complete reaction of $9.6\text{g}$ of magnesium?

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• Question 8Oct/Nov 2024, paper 11Multiple choice1 mark

  What is the relative molecular mass, $M_{\text{r}}$, of sulfuric acid, ${\text{H}}_2{\text{SO}}_4$?

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• Question 8Oct/Nov 2023, paper 11Multiple choice1 mark

  The equation for the combustion of methane is shown. $${\text{CH}}_4+2{\text{O}}_2\to {\text{CO}}_2+2{\text{H}}_2\text{O}$$ Which mass of methane produces $36\text{ g}$ of water?

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• Question 11May/June 2026, paper 11Multiple choice1 mark

  Which formula gives the $M_{\mathrm{r}}$ of lead(II) bromide?

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• Question 17Oct/Nov 2025, paper 11Multiple choice1 mark

  What are the units of concentration?

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• Question 9Oct/Nov 2024, paper 11Multiple choice1 mark

  The equation for the production of ammonia, ${\text{NH}}_3$, is shown. $${\text{N}}_2(\text{g})+3{\text{H}}_2(\text{g})\to 2{\text{NH}}_3(\text{g})$$ Which mass of nitrogen is required to make 51 tonnes of ammonia?

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• Question 25Oct/Nov 2023, paper 11Multiple choice1 mark

  Zinc oxide reacts with carbon to produce zinc. Which equation represents this reaction?

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• Question 7May/June 2026, paper 12Multiple choice1 markHas a diagram

  The diagram represents phosphoric acid. What is the molecular formula for phosphoric acid?

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• Question 7Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  The electronic configurations of atoms Q and R are shown. Q and R form an ionic compound. What is the formula of the compound?

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• Question 9Oct/Nov 2024, paper 12Multiple choice1 mark

  Which symbol equation represents the reaction between aqueous sodium hydroxide and dilute sulfuric acid?

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• Question 8Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The diagram shows the structure of a molecule of ethyl ethanoate. What is the molecular formula of a molecule of ethyl ethanoate?

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• Question 8May/June 2026, paper 12Multiple choice1 markHas a diagram

  The equation for the complete combustion of methane, ${\mathrm{C}\mathrm{H}}_4$, is shown.

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• Question 10Oct/Nov 2025, paper 12Multiple choice1 mark

  Which equation represents the complete combustion of butane, ${\text{C}}_4{\text{H}}_{10}$?

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• Question 10Oct/Nov 2024, paper 12Multiple choice1 mark

  What is the relative formula mass of magnesium bromide?

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• Question 9Oct/Nov 2023, paper 12Multiple choice1 mark

  The formula of a compound containing element X is ${\mathrm{N}\mathrm{a}}_2{\mathrm{X}}_2{\mathrm{O}}_3$. The relative formula mass of the compound is 158. What is the relative atomic mass of X?

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• Question 9May/June 2026, paper 12Multiple choice1 mark

  Four units are listed. 1 ${\mathrm{d}\mathrm{m}}^3\mathrm{/}\mathrm{m}\mathrm{o}\mathrm{l}$ 2 $\mathrm{g}\mathrm{/}{\mathrm{d}\mathrm{m}}^3$ 3 $\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{/}{\mathrm{d}\mathrm{m}}^3$ 4 $\mathrm{g}\mathrm{/}\mathrm{m}\mathrm{o}\mathrm{l}$ Which units are units of concentration?

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• Question 11Oct/Nov 2025, paper 12Multiple choice1 mark

  What is the relative formula mass of calcium sulfate, ${\text{CaSO}}_4$?

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• Question 8Oct/Nov 2024, paper 13Multiple choice1 mark

  Magnesium burns in oxygen to form magnesium oxide. The equation for the reaction is shown. $$2\text{Mg}+{\text{O}}_2\to 2\text{MgO}$$ Which mass of magnesium oxide is formed when $48\text{ g}$ of magnesium is burned?

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• Question 10Oct/Nov 2023, paper 12Multiple choice1 mark

  Limestone is used to reduce sulfur dioxide emissions from coal-fired power stations. The equation for the reaction is shown.

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• Question 9May/June 2026, paper 13Multiple choice1 markHas a diagram

  The diagram shows a model of an organic molecule. What is the molecular formula of this organic molecule?

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• Question 4Oct/Nov 2025, paper 13Multiple choice1 markHas a diagram

  The electronic structures of two atoms, P and Q, are shown. P and Q combine together to form a compound. What is the type of bonding in the compound, and what is the formula of the compound?

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• Question 9Oct/Nov 2024, paper 13Multiple choice1 mark

  Propane, ${\text{C}}_3{\text{H}}_8$, is burned in a limited amount of oxygen. Which equation represents this reaction?

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• Question 7Oct/Nov 2023, paper 13Multiple choice1 markHas a diagram

  The equation represents the reaction between solid magnesium oxide and dilute hydrochloric acid to form magnesium chloride and water.

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• Question 10May/June 2026, paper 13Multiple choice1 mark

  What is the relative formula mass of ammonium nitrate, ${\mathrm{N}\mathrm{H}}_4{\mathrm{N}\mathrm{O}}_3$?

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• Question 10Oct/Nov 2025, paper 13Multiple choice1 mark

  Which statement defines the term molecular formula?

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