Question

A + B + CD is:
a. How will the reaction rate change if [A] is doubled?

Answer 1

Explanation:

A + B + C → D

Given rate law of the reaction :

$R=k[A]^2[B]$

a) Rate of the reaction  if [A] is doubled = R'

$R'=k[2A]^2[B]=4k[A]^2[B]$

R' = 4 × R

The rate of the reaction will change by factor of 4.

b) Rate of the reaction  if [B] is  reduced to quarter = R'

$R'=k[A]^2[\frac{B}{4}]=0.25k[A]^2[B]$

R' = 0.25 × R

The rate of the reaction will change by factor of 0.25.

c) Rate of the reaction  if [C] is increased by 3 times= R'

Rate law of the reaction :

$R'=k[A]^2[B]$

As we can see that [C] does not appears in rate law of the reaction, which means that rte of the reaction is independent of [C].

R' = R

The rate of the reaction will remain the same.

The expected rate constant value for this experiment:

$R=k[A]^2[B]$

$k=\frac{R}{[A]^2[B]}$