Stoichiometry — IGCSE Sciences - Co-Ordinated (0973) questions by topic
Stoichiometry questions require the ionic equation for a silver bromide precipitate, matching molecular formulae to displayed structures, naming compounds from a given list, and comparing nitrogen-to-oxygen ratios across oxides of nitrogen, worth from 1 to 11 marks.
Identify, state and explain lead the command words in this IGCSE Co-ordinated Sciences topic, with calculate and describe also common: calculate a ratio precisely rather than estimate it. 24 real questions from 2023 to 2025 papers make up this page. Practise each formula and equation, then submit for instant marking so a wrongly balanced ionic equation is caught before it is repeated across several similar questions.
May–June 2025, Paper 21
What is the balanced equation for the combustion of hydrogen? A 2H + O - H2O B H2 + O2 - H2O C H2 + O - H2O D 2H2 + O2 - 2H2O
Answer this question and get it marked →Which description of mass is used to define relative atomic mass, Ar? A the mass of 1/12 of a mole of 12C atoms B the mass of one mole of 12C atoms C the mass of 1/12 the mass of…
Answer this question and get it marked →Which quantities, when measured at room temperature and pressure, contain one mole of oxygen molecules? 1 16 g of oxygen molecules 2 12 dm3 of oxygen molecules 3 the Avogadro…
Answer this question and get it marked →May–June 2025, Paper 22
Ammonia decomposes when heated in a sealed container in the presence of an iron catalyst. The equation for the reaction is shown. 2NH₃(g) → N₂(g) + 3H₂(g) 40.0 dm³ of ammonia is…
Answer this question and get it marked →A nucleus of ²³⁸₉₂U undergoes radioactive decay to produce a nucleus of thorium (Th) and an alpha particle. Which equation shows this decay? A ²³⁸₉₂U → ²³⁸₉₃Th + ⁰₋₁α B ²³⁸₉₂U →…
Answer this question and get it marked →May–June 2025, Paper 31
Sulfuric acid has the formula H2SO4. Determine the relative molecular mass, Mr, of sulfuric acid. [Ar: H, 1; O, 16; S, 32] relative molecular mass = ...............
Answer this question and get it marked →May–June 2025, Paper 32
Calcium carbonate has the formula CaCO3. State the number of different elements shown in this formula.
Answer this question and get it marked →May–June 2025, Paper 42
The ionic compound sodium sulfate contains the ions Na+ and SO4^2-. Determine the formula of sodium sulfate. formula = ...........
Answer this question and get it marked →A student investigates the reaction between dilute hydrochloric acid and solid pieces of calcium carbonate. The balanced symbol equation for the reaction is shown. Complete the…
Answer this question and get it marked →May–June 2024, Paper 11
Hydrogen peroxide is a compound. A molecule of hydrogen peroxide can be represented as shown (two oxygen atoms and two hydrogen atoms). [Diagram: H-O-O-H molecule; key shows…
Answer this question and get it marked →May–June 2024, Paper 12
Which oxides of nitrogen have the same ratio of nitrogen atoms to oxygen atoms? 1 N2O 2 NO 3 NO2 4 N2O4 A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4
Answer this question and get it marked →Different minerals contain different elements. Which mineral contains three non-metallic elements? A chalcopyrite CuFeS2 B cryolite Na3AlF6 C gypsum CaSO4.2H2O D ilmenite FeTiO3
Answer this question and get it marked →May–June 2024, Paper 21
The equation for the combustion of magnesium is 2Mg + O2 - 2MgO. What is the mass of magnesium oxide formed from 12 g of magnesium? (Ar: Mg 24, O 16) A 20 g B 24 g C 40 g D 80 g
Answer this question and get it marked →May–June 2024, Paper 22
W, X, Y and Z are diagrams representing atoms and molecules (circles representing atoms; molecules contain joined circles). Which statement is correct? [Diagrams W, X, Y, Z:…
Answer this question and get it marked →The equation for the reaction of sodium with water is 2Na(s) + 2H2O(l) - 2NaOH(aq) + H2(g). Which mass of sodium produces 30 cm3 of hydrogen? (Ar Na = 23; molar gas volume = 24…
Answer this question and get it marked →May–June 2024, Paper 32
A teacher reacts sodium with water. Hydrogen and aqueous sodium hydroxide are the products. Balance the symbol equation: 2Na + ...H2O - ...NaOH + H2
Answer this question and get it marked →May–June 2024, Paper 41
Magnesium sulfate contains magnesium ions, Mg2+, and sulfate ions, SO4 2-. Determine the formula of magnesium sulfate.
Answer this question and get it marked →October–November 2024, Paper 31
Fig. 2.1 shows the formulae of some substances. CH₄ Cl₂ H₂O NaCl NH₃ CO₂ O₂ HCl Identify the formula of the substance that is the main constituent of natural gas.
Answer this question and get it marked →May–June 2023, Paper 12
The structures of some compounds are shown. 1 ethanol structure (CH3CH2OH), formula C2H6O 2 O=C=O, formula CO2 3 nitric acid structure (H-O-N(=O)-O), formula HNO3 4 O=S=O, formula…
Answer this question and get it marked →May–June 2023, Paper 21
Which symbol equation is not balanced? A C3H8 + 5O2 - 3CO2 + 4H2O B Fe3O4 + 2H2 - 3Fe + 2H2O C Mg(OH)2 + 2HCl - MgCl2 + 2H2O D 2Na + 2H2O - 2NaOH + H2
Answer this question and get it marked →May–June 2023, Paper 22
Aqueous potassium bromide reacts with aqueous silver nitrate to produce a cream precipitate. What is the ionic equation for this reaction? A Ag+(aq) + Br-(aq) - AgBr(s) B Ag2+(aq)…
Answer this question and get it marked →May–June 2023, Paper 32
The list gives the names of six compounds: aluminium oxide, ammonium nitrate, carbon dioxide, lead bromide, sodium chloride, sulfur dioxide. Each compound may be used once, more…
Answer this question and get it marked →May–June 2023, Paper 41
A student investigates the rate of reaction between dilute hydrochloric acid, HCl, and magnesium, as shown in Fig. 8.1. Magnesium chloride, MgCl2, and hydrogen gas, H2, are made.…
Answer this question and get it marked →October–November 2023, Paper 21
When magnesium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is released. The equation is MgCO3 + 2HCl - MgCl2 + CO2 + H2O. Which volume of carbon dioxide,…
Answer this question and get it marked →Other IGCSE Sciences - Co-Ordinated topics
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