A student investigated the reaction of magnesium with dilute hydrochloric acid at 25 °C: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g). The volume of hydrogen gas given off was measured and plotted against time.

1. aWrite the ionic equation for the reaction. [2]
2. bDescribe a 'dot and cross' diagram to show the bonding in magnesium chloride, MgCl₂ (draw it on paper). [3]
3. cName the apparatus used to collect and measure the volume of the gas. [2]
4. dState one observation, other than bubbles, that could be made during the reaction. [1]
5. eHow long does it take for the reaction to stop? [1]
6. fWhat is the volume of hydrogen gas produced after 25 seconds? [1]
7. gWhere on the graph is the rate of reaction highest? Give an explanation for your answer. [2]
8. hDescribe how the graph would change if the experiment was repeated at 15 °C. [2]

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