How to find concentration with initial concentration and moles consumed?

Question

Plot on to graph moles of S2O8 vs time to achieve M/s.

The initial concentration of S2O8: 0.05M (added is 2.5mL of 0.200M, but it was diluted so 0.200 x 2.5/10mL = 0.05M). 

Below is the time (s) and moles consumed.

188s - 0.00002 moles

362s - 0.00004 moles

548s - 0.00006 moles

740s - 0.00008 moles

1001s - 0.0001 moles

I was told to plot concentration vs time then subtract the moles, but I'm confused how to do that. 

Answer 1

This is an integrated rate law thing, or just stoichiometry with the change in concentration of 1 thing allowing you to determine the change in concentration of the other thing.

So if the moles of the reactant decreases by x, the products will increase by x, based on the relationship of the coefficients of each thing. You can make excel do all of this for you, and it helps to make an ICE box.