Question

A reaction in which a , b , and c react to form products is zero order in a , one-half order in b , and second order in
c. by what factor does the reaction rate change if [b] is doubled (and the other reactant concentrations are held constant)? -g

Answer 1

For the reaction: A + B + C = products
when the rate law is:
r = K [A]^0 [B]^0.5 [C]^2 
  = K [B]^0.5 [C]^2
so the overall order of the reaction is 0 + 0.5 + 2 = 2.5
when the concentration of B is doubled and the concentrations of A and C are held constant so,
r1= [B(1)]^0.5  and r2 = [B(2)]^0.5 
∴ r2/r1 = [B(2)]^0.5 / [B(1)]^0.5 = 2^0.5 / 1^0.5 = 1.414
∴ the reaction will speed up 1.414 times