Question

What is the rate constant of a reaction if rate = 0.2 (mol/L)/s, [A] and [B] are each 3 M, m = 1, and n = 2?

Answer 1

m= 1 and n = 2
( m+ n = 1 +2 = 3)

rate = K [A] [B]^2

0.2 = K * 3 * 3 ^2
0.2 = K * 3 * 9
K = 0.2 / 27
K = 7.408 * 10 ^ -3 m^-2 s^-1

Answer 2

Answer : The rate constant of a reaction is,
`7.407* 10^(-3)M^(-2)s^(-1)`

Solution :

The general rate law expression is,

`rate=k[A]^m[B]^n`

where,

k = rate constant

[A] and [B] are the concentrations

m is the order of reactant A and n is the order of reactant B

Now put all the given values in the above rate law expression, we get the value for rate constant.

`0.2Ms^(-1)=k* (3M)^1* (3M)^2`

`k=7.407* 10^(-3)M^(-2)s^(-1)`

Therefore, the rate constant of a reaction is,
`7.407* 10^(-3)M^(-2)s^(-1)`