Excess marble chips (calcium carbonate) was put in a beaker containing 100 cm3 of dilute hydrochloric acid. The beaker was then placed on a balance and the total loss in mass recorded after every two minutes as shown in the table below

Time (minutes)	0	2	4	6	8	10
Total loss in mass (g)	0	1.8	2.45	2.95	3.2	3.3

(a) Why was there less in mass ( 1 mk)

(b) Calculate the average rate of loss in mass between

(i)) 0 and 2 minutes ( 1 mk)

(ii) 6 and 8 minutes ( 1 mk)

(iii) Explain the difference in the average rates of reaction in (b) (i) and (ii) above ( 2 mks)

(c) Write the equation for the reaction which takes place in the beaker ( 1 mk)

(d) State three ways in which the rate of the reaction above could be increased. ( 3 mks)

(e) The solution in the beaker was evaporated to dryness explain what would happen if the beaker and its contacts were left in the laboratory overnight ( 2 mks)

(f) Finally some water was added to the contents of the beaker when aqueous sodium sulphate was added to the content of the beaker a white precipitate was formed

(i) State one use of the substances identified in (f)(i) above