This question is about salts - AQA - GCSE Chemistry - Question 5 - 2021 - Paper 1

$H^+ + OH^- \rightarrow H_2O$

Copper carbonate and copper oxide only.

Step 2 (to speed up the reaction) involves warming the sulfuric acid, which can increase the reaction rate by providing more energy to the particles involved.

Step 5 is to ensure that all the hydrochloric acid reacts with magnesium oxide, preventing any unreacted acid from remaining in the solution.

Step 6 is to remove the excess magnesium oxide, which is accomplished by filtering the mixture.

The filtrate should be evaporated gently using a boiling water bath or an electric heater to prevent the crystals from forming too quickly.

First, calculate the moles of iron: $\text{moles Fe} = \frac{14 g}{56 g/mol} = 0.25 \text{ mol}$. Next, from the reaction equation, 2 moles of Fe react with 3 moles of Cl₂, meaning 0.25 moles of iron would require 0.375 moles of chlorine: $\text{moles Cl₂} = 0.25 \text{ mol} \times \frac{3}{2} = 0.375 \text{ mol}$. Finally, the volume of chlorine needed is: $\text{Volume Cl₂} = 24 dm³/mol \times 0.375 mol = 9.0 dm³$.