1.1. A series of experiments was carried out to investigate the factors which affect the rate of reaction between calcium carbonate and dilute hydrochloric acid.

CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g)

• 50.0 cm³ of hydrochloric acid was added to 10 g of calcium carbonate (an excess) in a conical flask placed on an electronic balance.

• The loss in mass of the flask and its contents was recorded every 30 seconds for 10 minutes.

• The experiment was repeated using different sized pieces of calcium carbonate, a different concentration of hydrochloric acid or a different temperature.

The results of Experiment 1 are shown on the graph.

Draw curves on the graph to show the results you would expect for Experiments 2, 3 and 4. Label the curves 2, 3 and 4.

1.2. Determine the initial rate of reaction for Experiment 1.

You must show your working on the graph. Include units in your answer.

 Initial rate of reaction .........................................................

1.3. A student was required to devise an alternative method of carrying out this experiment that involved collecting the gas produced.

Outline the procedure that the student could use, including a diagram and the measurements needed.