(Solved): 1. Marble chips (calcium carbonate) react with dilute hydrochloric acid calcium carbonate + hydroc ...

1. Marble chips (calcium carbonate) react with dilute hydrochloric acid calcium carbonate + hydrochloric acid ? calcium chloride + carbon dioxide + water A student wanted to find out if the size of the marble chips made a difference to how fast the reaction took place. She first weighed on a balance a conical flask containing 50 cm³ of hydrochloric acid, a plug of cotton wool, and a weighing boat containing 10 g of small marble chips. She then added the small marble chips to the acid, placed the weighing boat back on the balance, and placed the cotton wool on the neck of the flask. She recorded the mass every 2 minutes for a total of 12 minutes. She repeated the experiment but this time used the same mass (10g) of large marble chips. In both experiments there was some marble left in the flask when the reaction stopped. The table below shows the results of the two experiments. Time/min 0 2 4 6 8 10 12 0.00 0.40 0.72 0.91 1.04 1.04 Loss in mass using small chips /g 1.04 Loss in mass using 0.00 0.28 0.52 0.69 0.83 0.93 1.04 large chips /g (a) Explain how the results on the table were calculated (b) Plot the two sets of results on the same axes (c) Explain the purpose of the cotton wool (d) Explain the loss in mass in the two experiments (e) Explain why this method is suitable for the reaction. (1) Describe a different method that could have been used to measure the rate of this reaction (g) State and explain the effect of the marble chip size on the rate of the reaction. Refer to your graph in (a) and to the collision theory in your answer.