I did a lab, an kinetics lab (iodide clock) and in my lab report I have to calculate the initial rate in mol L-1 s-1 and I'm not sure how to do that. I have the [I-] and [S2O82-] in mol L-1 already.

The reagents are [KI] [NaCl] [Na2S2O3] [Na2SO4] [K2S2O8].