Chemistry · May / June 2023 · Paper 12 · Question 16

The volume of gas produced by the reaction of 100 cm³ of hydrochloric acid with an excess of calcium carbonate is measured in two experiments. The volumes of gas are measured at r.t.p. and the results are shown. | time / s | 0 | 30 | 60 | 90 | 120 | 150 | 180 | 300 | |---|---|---|---|---|---|---|---|---| | volume of gas in experiment 1 / cm³ | 0 | 20 | 30 | 38 | 44 | 48 | 50 | 50 | | volume of gas in experiment 2 / cm³ | 0 | 30 | 42 | 55 | 65 | 70 | 75 | 75 | Which one change in conditions to experiment 1 gives the results for experiment 2? Assume all other conditions are unchanged.

1. AA greater volume of acid is added.
2. BA higher concentration of acid is used.
3. CSmaller pieces of calcium carbonate are used.
4. DThe temperature of the acid is higher.

As printed in the paper