A student performed two experiments to establish how effective manganese (IV) oxide was as a catalyst for the decomposition of hydrogen peroxide. The results below were obtained by carrying out these experiments with two different quantities of manganese(IV) oxide. The volume of the gas produced was recorded against time.
Time/s 0, 30,60,90,120,150,180,210
Volume for 0.3g/cm^3 0, 29,55,79,98,118,113,146
Volume for 0.5g/cm^3 0, 45,84,118,145,162,174,182
b Plot a graph of the results.