CIE iGCSE Co-Ordinated Science C9.4 Reactivity series Exam Style Questions Paper 3
Question
(a) A student adds calcium and copper to separate test-tubes of cold water. Describe the reaction, if any, for each metal.
▶️Answer/Explanation
Calcium: Gas evolved / metal dissolves / white insoluble solid forms.
Copper: No change.
(b) The student reacts copper carbonate with dilute sulfuric acid. Copper(II) sulfate, carbon dioxide and water are made.
(i) Complete the word equation for this reaction.
▶️Answer/Explanation
Copper carbonate + sulfuric acid → copper sulfate + carbon dioxide + water.
(ii) Carbon dioxide gas is a greenhouse gas. State the name of one other greenhouse gas.
▶️Answer/Explanation
Methane.
(iii) The formula of copper(II) sulfate is CuSO4. State the number of different elements and the total number of atoms shown in this formula.
▶️Answer/Explanation
Number of elements: 3 (Copper, Sulfur, Oxygen).
Number of atoms: 6 (1 Cu, 1 S, 4 O).
(c) Copper oxide, CuO, is reduced to copper, Cu, by heating with carbon. The equation for the reaction is shown.
2CuO + C → 2Cu + CO2
(i) Explain how the equation shows that copper oxide, CuO, is reduced.
▶️Answer/Explanation
Copper oxide loses oxygen, which is the definition of reduction.
(ii) The reaction between copper oxide and carbon is exothermic. State what is meant by exothermic.
▶️Answer/Explanation
Exothermic reactions release energy to the surroundings, usually in the form of heat.
(iii) Name a metal, other than copper, that can be extracted from its ore by heating with carbon.
▶️Answer/Explanation
Iron.