[EriLynn~]

 i cant seem to process the steady state approximation method very well..
i know we assume that the d[intermediate]/dt = 0 ... but im not too sure as to what else to do...
here is an example question for my studying that i cant get....


Match the expressions to complete the equations, making use of the Steady State Approximation.

A) 2(k1)(k3)[A]^2[ B] / (k2)[D]
B) (k1)[A][ B] / (k3)[A]
C) 2(k1)(k3)[A]^2[ B] / (k2)[D] +(k3)[A]
D) (k1)[A][ B] / (k2)[D] + (k3)[A]
E) 2(k1)[A][ B]
F) (k1)[A][ B] - (k2)[C][D] - (k3)[A][C]
G) (k1)[A][ B] / (k2)(k3)[A][D]
H) None of the above

match with!! _______
1. -d[A]/dt (in all instances)
2. d[D]/dt (when k3 >> k1 =k2)
3. d[D]/dt (when k3 <<k1=k2)
4. d[C]/dt
5. =[C]

I know it looks like a lot but bare with me ...
I tried this and i got
1= C
2 = ??
3= ??
4= F
5= D

i dont even knwo if those are right, but i was more confident on those than the other two...
i really really do not understand what to do with the k3>> k1=k2 stuff.... i'm completely lost when it comes to that...
any steps to follow?? thanks