Question

(I just need part B)

Consider the reaction

A+2B⇌C

whose rate at 25 ∘C was measured using three different sets of initial concentrations as listed in the following table:

Trial	[A] (M)	[B] (M)	Rate (M/s)
1	0.50	0.030	9.0×10−3
2	0.50	0.060	1.8×10−2
3	1.00	0.030	3.6×10−2

Part A

Part complete

What is the rate law for this reaction?

Express the rate law symbolically in terms of k, [A], and [B].

rate =

k[A]2[B]

Part B

Calculate the initial rate for the formation of C at 25 ∘C, if [A]=0.50M and [B]=0.075M.

Express your answer to two significant figures and include the appropriate units.

Answer 1

Part B :

Rate of reaction = k.[A]²[B]

9.0×10^-3M.s^-1 = k ×(0.50 M)²(0.50 M)

k = rate constant = 7.2×10^-2 M^-2.s ^-1

Initial rate of reaction = k.[A]²[B] = 7.2×10^-2 M^-2.s^-1 × (0.50 M)².(0.075 M) = 0.135×10^-2 M/s

Initial rate of reaction = initial rate for formation of C = 1.35×10^-3 M/s

= 1.4×10^-3 M/s. (Answer)