Lesson 5.2.1

5.2.1 Balanced equations and reacting masses Quiz: Pearson Edexcel Chemistry, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.2.1, Balanced equations and reacting masses: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 5: Formulae, Equations and Amounts of Substance, written with Revision Ninja.

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The 20 questions

  1. Which equation is balanced correctly for magnesium reacting with hydrochloric acid?

    • Mg + 2HCl -> MgCl2 + 2H2
    • 2Mg + HCl -> Mg2Cl + H2
    • Mg + 2HCl -> MgCl2 + H2
    • Mg + HCl -> MgCl + H2

  2. What mass of calcium chloride, CaCl2, is formed from 10 g of calcium carbonate reacting with excess hydrochloric acid? (CaCO3 = 100, CaCl2 = 111)

    • 22.2 g
    • 11.1 g
    • 10.0 g
    • 5.6 g

  3. What mass of hydrogen is produced when 2.4 g of magnesium reacts with excess acid? (Mg = 24, H2 = 2)

    • 0.20 g
    • 0.10 g
    • 2.40 g
    • 0.40 g

  4. What mass of magnesium oxide forms when 4.86 g of magnesium burns in excess oxygen? (Mg = 24.3, MgO = 40.3)

    • 9.72 g
    • 6.48 g
    • 8.06 g
    • 4.86 g

  5. What mass of iron forms from 16.0 g of iron(III) oxide reacting with carbon monoxide? (Fe2O3 = 159.7, Fe = 55.8)

    • 5.6 g
    • 22.4 g
    • 16.0 g
    • 11.2 g

  6. What mass of sodium hydroxide is needed to neutralise 0.10 mol of sulfuric acid? (NaOH = 40)

    • 2.0 g
    • 4.0 g
    • 8.0 g
    • 16 g

  7. What mass of carbon dioxide forms when 6.0 g of carbon burns completely? (C = 12, CO2 = 44)

    • 6.0 g
    • 22 g
    • 44 g
    • 11 g

  8. In a neutralisation reaction between sulfuric acid and sodium hydroxide, what is the mole ratio of NaOH to H2SO4?

    • 1 : 1
    • 1 : 2
    • 2 : 1
    • 3 : 1

  9. How many moles of O2 are needed to react with 4 mol of H2 in 2H2 + O2 -> 2H2O?

    • 2 mol
    • 1 mol
    • 4 mol
    • 8 mol

  10. What is the ionic equation for the neutralisation of hydrochloric acid by sodium hydroxide?

    • H+ + OH- -> H2O
    • HCl + OH- -> H2O + Cl-
    • H+ + Cl- -> HCl
    • Na+ + Cl- -> NaCl

  11. Which full equation with state symbols is correct for magnesium reacting with hydrochloric acid?

    • Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)
    • Mg(aq) + 2HCl(s) -> MgCl2(g) + H2(l), which uses the wrong state symbols for every species in the equation
    • Mg(l) + 2HCl(g) -> MgCl2(s) + H2(aq), which reverses the physical states of the reactants and products
    • Mg(g) + 2HCl(l) -> MgCl2(l) + H2(s), which gives magnesium as a gas and hydrogen as a solid product

  12. 0.5 mol of magnesium reacts with an excess of oxygen to form magnesium oxide, 2Mg + O2 -> 2MgO. How many moles of MgO form?

    • 0.25 mol
    • 0.5 mol
    • 1.0 mol
    • 2.0 mol

  13. What mass of oxygen is needed to burn 6.0 g of methane? (CH4 = 16, O2 = 32; CH4 + 2O2 -> CO2 + 2H2O)

    • 12 g
    • 6.0 g
    • 24 g
    • 48 g

  14. What mass of sodium carbonate, Na2CO3, reacts with 0.20 mol of hydrochloric acid? (Na2CO3 = 106)

    • 2.1 g
    • 10.6 g
    • 21.2 g
    • 5.3 g

  15. What mass of copper(II) oxide reacts with 0.50 mol of sulfuric acid? (CuO = 79.5)

    • 19.9 g
    • 39.8 g
    • 159 g
    • 79.5 g

  16. What mass of carbon dioxide is produced by heating 25 g of calcium carbonate fully? (CaCO3 = 100, CO2 = 44)

    • 11 g
    • 25 g
    • 22 g
    • 44 g

  17. What mass of hydrogen forms when 5.0 g of zinc (Ar 65.4) reacts with excess acid?

    • 0.08 g
    • 0.15 g
    • 0.31 g
    • 5.0 g

  18. Why is the mole ratio from a balanced equation essential in reacting mass calculations?

    • It gives the exact mass of each product directly from the balanced equation, without any further calculation being needed
    • It removes the need for molar masses in any reacting mass calculation, since the ratio gives the masses directly
    • It gives the ratio of amounts that react and are formed, which converts masses through moles
    • It shows the speed of the reaction, which is needed to work out how much product forms in a given time

  19. Explain why 2 mol of HCl are needed for 1 mol of CaCO3.

    • HCl is a diatomic molecule that reacts only in pairs, so two moles are always needed for the reaction to proceed
    • CaCO3 has two chlorine atoms that react with the HCl, so two moles of hydrochloric acid are needed for each mole
    • Each CO3 2- ion needs two H+ ions to form CO2 and H2O, so the balanced equation uses two HCl
    • The reaction is faster with two HCl molecules present, so the balanced equation is written with two of them

  20. Which statement about state symbols is correct?

    • (aq) means a gas dissolved in an acid solution, while (s) means soluble and (l) means limited in the mixture
    • (s) means soluble in water and (aq) means a solid that has been ground to a fine powder before reacting
    • (l) means limited quantity of the reagent, while (g) means the gas-phase product of the reaction in the flask
    • (aq) means dissolved in water, while (s), (l) and (g) mean solid, liquid and gas

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