Rate expressions?

Question

How do i answer this?

Given the following data:

[C]--------[D]--------Initial Rate
mol/L---mol/L-----mol/Ls
0.24-----0.10-----2.1 x 10 ^-2 (0.021)
0.48-----0.10-----8.4 x 10 ^-2 (0.084)
0.72-----0.20-----3.8 x 10 ^-1 (0.38)

"Determine the rate expression for the reaction
C + 2D --> E + 5F. Determine the value of the rate constant k."

Answer 1

Look at the first two. Holding D constant, doubling C quadruples the rate - therefore it's second order in C.

Now compare the first and third. C is tripled, so we know that will account for a 9-fold increase in the rate, but D has doubled also, and the rate has gone up 18-fold, which is double 9. Therefore it's first order in D.

Now you can carry on.