3. Ok, what have you learnt when you increase the concentration of a reactant?

Increasing the concentration is increasing the number of molecules of S2O8. Therefore, the

__collisional frequency__ is increased. Let's say there is a fine rain hitting the ground. The 'concentration' is the amount of raindrops hitting a certain area. If the rain becomes a downpour, there are more drops hitting the same area, and the ground gets wet faster! So, increasing concentration will increase the rate of reaction.

4. I think I did something wrong yesterday... was too tired I think. Let me re write the equation (you are sure this is right?)

The 4th question is still unclear. Was there x in front of S2O8 and y in front of I2 in the equation? If so, you need to consult your graph. Find the point where you obtained the maximum rate of reaction. This point should give your values of x and y.