4. A student added magnesium ribbon to an excess of dilute sulphuric acid and measured the volume of hydrogen gas produced. The reaction stopped when all the mognesium was used up. The results are shown in the table Time/s & 0 & 10 & 20 & 30 & 40 & 50 & 60 }(l) Volume of gas/cm & 0 & 20 & 32 & 40 & 43 & 45 & 45 a) Calculate the time taken for the volume: (i) To increase from 20 mathrm(~cm)^3 to 40 mathrm(~cm)^3 (ii) To increase from 43 mathrm(~cm)^3 to 45 mathrm(~cm)^3 (2) b) Calculate the change in volume of the gas: (i) Between 0 and 20 seconds (ii) Between 40 and 60 seconds (2) c) Calculate the AVERAGE REACTION RATE, in mathrm(cm)^3 mathrm(~s)^-1 . (i) between 0 and 20 seconds (ii) between 40 and 60 seconds (2)

a) (i) The time taken for the volume to increase from to is seconds.(ii) The time taken for the volume to increase from to is seconds.b)(i) The change in volume of the gas between and seconds is .(ii) The change in volume of the gas between and seconds is .c)(i) The average reaction rate between and seconds is .(ii) The average reaction rate between and seconds is .