Molarity of O2 , M = Number of moles / volume in
L
                         Â
= 1.6x10-2 mol / 0.340 L
                         Â
= 0.047 mol/L
                         Â
= 0.047 M
Average rate , r = Concentration of O2 produced /
time interval
                    Â
= 0.047 M / 12.0 s
                   Â
= 3.92x10-3 M/s
Therefore average rate of the reaction over this time interval
is 3.92x10-3 Ms-1
