An experiment was carried out at 25 °C by dissolving an unknown mass of magnesium ribbon into excess 1 mol dm–3 hydrochloric acid. The volume of gas produced over a period of 6 minutes was measured using a gas syringe. The result was plotted as shown in Figure 1 Time (min)

Figure 1 Volume of gas produced against time

a)Write a balanced equation for its reaction with hydrochloric acid.

(2 marks)
Use the data from Figure 1
to determine the total volume of gas produced (1mark)

to calculate the moles of gas produced at STP (2 marks)
[1 mole of any gas at STP has a volume of 22 400 cm3.]

to calculate the mass of limestone magnesium used.

(2 marks)

(i)What is meant by the term ‘rate of reaction’?

(1 mark )

Besides temperature, identify TWO other factors that can affect the rate of the reaction.

marks)