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.
Learn this properly: Reactivity of MetalsA student is given a piece of solid copper sulfate and water, and is asked to prepare pure, dry crystals of copper sulfate by reacting an acid with an insoluble base.
The student has dilute sulfuric acid and solid copper oxide (an insoluble base).
Describe how the student should prepare pure, dry crystals of copper sulfate from sulfuric acid and copper oxide. (6 marks)
Molten lead bromide (PbBr2) can be broken down by electrolysis using inert electrodes. Lead is produced at one electrode and bromine at the other.
(a) Name the electrode (positive or negative) at which the lead is produced, and explain why lead forms there. (2 marks)
(b) Write the half equation for the reaction at the negative electrode. (2 marks)
The reactivity series places metals in order of how readily they react.
A student added a small piece of zinc to copper(II) sulfate solution. A reaction occurred: the blue colour faded and an orange-brown solid formed on the zinc.
(a) Name the type of reaction that has taken place. (1 mark)
(b) Write a balanced symbol equation for the reaction between zinc and copper(II) sulfate. (2 marks)
A student measured the pH of four different acids, each at the same concentration of 0.1 mol/dm³, using a pH meter. The results are shown in the table.
| Acid | pH at 0.1 mol/dm³ |
|---|---|
| Hydrochloric acid | 1.0 |
| Nitric acid | 1.0 |
| Ethanoic acid | 2.9 |
| Citric acid | 2.2 |
(a) Using the data, identify which acids in the table are strong acids and which are weak acids. (2 marks)
(b) Explain, in terms of ionisation, why a strong acid has a lower pH than a weak acid of the same concentration. (1 mark)
When iron is extracted from iron(III) oxide in a blast furnace, the iron(III) oxide reacts with carbon monoxide:
Fe2O3+3CO→2Fe+3CO2
Explain, in terms of oxygen, why the iron(III) oxide is reduced in this reaction. (2 marks)
An alkali is a soluble base. When an acid reacts with an alkali, a neutralisation reaction occurs.
State the formula of the ion produced by all alkalis in solution that makes them alkaline. (1 mark)