EDIT: Self-solved. Obviously it has to be the 300sec interval for each calculation. And ideally, corrosion speed had to be calculated real-time each second or even ms, to be as accurate as possible. Im just keeping this here, in case anyone ever wondered the same thing once.

Hello. I do know how Electroplating works, but there is one task I dont really understand how to solve it, since the teachers did not discuss it yet, but still want to see the task done.

Basically, it was about electroplating/galvanic corrosion. There is Magnesium and Iron.

We weighed the Magnesium in dry state before putting it in the liquid together with the Iron. (It was 100ml of NaCL of 0,1Mol liquid, mixed with water)

We weighed the Magnasium after 5, 10, 15min... etc. (Basically, every 5min) and noted down the mass. And with a multimeter, we got the amperage at these times.

We did not add extra amperage, but made use of the electrochemical potential of elements.

Now the task is to compare the weighed mass with the theoretical calculated mass of magnesium.

I understand, that the weighed mass of Magnesium is 'fake', because magnesium is in a wet state when taken out every 5min, to weigh the mass.

So, I do see logic in calculating the mass and comparing weighed mass with calculated mass.

My issue is: I dont exactly know if I am doing it wrong. To be able to get the mass, I calculated the corrosion speed. The corrosion speed is always different at given time, since the amperage also naturally changes.

Now, I can basically multiplay corrosion speed with the time delta t. (V * t) to get the mass delta m.

But what time do I need to take? Do I basically use 300, 600, 900, 1200 etc... (since it was in 5min steps) or do I uase only 300sec? Because amperage changes itself, so when it was 130mA at 300sec, then it is, 150mA at 900sec. My head says: I cant use 900sec to get the mass for 150mA, because until 300 sec, it was only 130mA, and it reached 150mA only at 900sec (which is actually not true either, because reaching 150mA was only at 900sec, but not even during the whole 300sec from 600-900sec.)

So, how exactly do I need to handle this, to stay fair and close enough to the real amperage changes, to get the mass changes?

So, do I use 300sec every time for each calculation, or do I actually use 300, 600, 900sec... etc