10 6
Christina investigates the reaction between magnesium and hydrochloric acid. Magnesium chloride and hydrogen are made. (a) Write down the balanced symbol equation for this reaction. .............................................................................................................................................. [2] (b) Look at the diagram. It shows the apparatus Christina uses. 20 40 60 80 100 cm3
gas syringe hydrochloric acid magnesium lump She measures the volume of gas in the syringe every 10 seconds. Look at the graph. It shows her results. 30 25 20 total volume of gas given off in cm3
15 10 5 0
(i)
0
10
20
30
40 50 60 time in seconds
80
90
At what time did the reaction finish? ........................................... seconds
(ii)
70
[1]
Calculate the rate of reaction for this reaction during the time interval 0 – 20 seconds. ........................................................................................................................................... ........................................................................................................................................... answer ........................................... cm3/s
Š OCR 2012
[1]