6 exam-style questions with full mark schemes and model answers. Write your own answer and the AI examiner marks it against the mark scheme.
A student places clean pieces of three different metals — magnesium, zinc and copper — into separate test tubes, each containing the same volume of dilute hydrochloric acid at the same temperature. They observe the rate at which bubbles of gas are produced.
Their results are shown in the table.
| Metal | Observation with dilute hydrochloric acid |
|---|---|
| magnesium | many bubbles produced very quickly |
| zinc | bubbles produced steadily |
| copper | no bubbles; no reaction |
Explain how these results allow the three metals to be placed in order of reactivity, and explain what the reactions (or lack of reaction) tell you about how each metal compares with hydrogen in the reactivity series. Use the results as evidence.
(6 marks)
An iron nail is placed into a blue solution of copper(II) sulfate. A displacement reaction occurs: the nail becomes coated with copper and the blue colour fades.
Fe+CuSO4→FeSO4+Cu
(a) Explain, in terms of the reactivity series, why iron is able to displace copper from copper(II) sulfate solution. (1 mark)
(b) This is a redox reaction. State, in terms of electrons, what happens to the iron atoms and what happens to the copper ions. (2 marks)
Chlorine, bromine and iodine are halogens in Group 7. A more reactive halogen can displace a less reactive halogen from a solution of its salt.
A student adds chlorine solution to a colourless solution of potassium iodide. A reaction occurs and the solution turns brown as iodine is formed.
(a) Write the balanced symbol equation for the reaction between chlorine and potassium iodide. (2 marks)
(b) Predict whether iodine would react if it were added to a solution of potassium chloride. Give a reason. (1 mark)
The alkali metals in Group 1 react with water. When a small piece of sodium is added to water, it fizzes, moves across the surface and produces a gas. The products are sodium hydroxide and hydrogen.
(a) Write the balanced symbol equation, including state symbols, for the reaction of sodium with water. (2 marks)
(b) Predict how the reaction of potassium with water would compare with that of sodium. (1 mark)
A student has three metals: magnesium, silver and calcium. The reactivity series (most reactive at the top) includes:
potassium > calcium > magnesium > zinc > iron > copper > silver
The student adds each metal in turn to cold water.
Predict which of the three metals will react with cold water, and which will not, using their positions in the reactivity series. (2 marks)
In a displacement reaction, a more reactive metal takes the place of a less reactive metal in a compound.
State what is meant by the term oxidation in terms of electrons. (1 mark)