i have to calculate the amount of aluminum dissoluted to form aluminum hydroxide for a specific time(say 90 minutes). The dissolution can be calculated using fardays laws... the relation is given as

aluminum dissoluted (m)= itM/ZF...

Faradays law is used to relate the current flow (I for time t ) to the amounts (m) of aluminum and hydroxide ions generated within the reactor. Z is the number of electrons transferred in the reaction at the electrode, M is the molecular weight (g /mol) and F is Faradays constant (96 486 C /mol).

But in my case as current value is changing with time what modification do i have to bring in the expression to calculate the the amount of Aluminum dissoluted? will simple integration or the arthematic average of the current values suffice the purpose? plzz help me out ...