Question

A reaction in which A, B, and C react to form products is first order in A, second order in B, and zero order in C. a. Write a rate law for the reaction. b. What is the overall order of the reaction? c. By what factor does the reaction rate change if [A] is doubled (and the other reactant concentrations are held constant)? d. By what factor does the reaction rate change if [B] is doubled (and the other reactant concentrations are held constant)? e. By what factor does the reaction rate change if [C] is doubled (and the other reactant concentrations are held constant)? f. By what factor does the reaction rate change if the concentrations of all three reactants are doubled?

Answer 1

Answer:

a. r = k. [A]¹. [B]².[C]⁰

b. 3

c. 2

d. 4

e. 1

f. 8

Explanation:

A reaction in which A, B, and C react to form products is first order in A, second order in B, and zero order in C.

a. Write a rate law for the reaction.

r = k. [A]¹. [B]².[C]⁰

where,

r is the rate of the reaction

k is the rate constant

[X]ⁿ are the molar concentrations of each reactant raised to its reaction order

b. What is the overall order of the reaction?

The overall order of reaction is the sum of the individual orders of reaction, that is, 1 + 2 + 0 = 3.

c. By what factor does the reaction rate change if [A] is doubled (and the other reactant concentrations are held constant)?

If A is doubled, then:

r' = k. [2A]¹. [B]².[C]⁰= 2 k. [A]¹. [B]².[C]⁰ = 2 . r

The factor is 2.

d. By what factor does the reaction rate change if [B] is doubled (and the other reactant concentrations are held constant)?

If B is doubled, then:

r' = k. [A]¹. [2B]².[C]⁰ = 4. k. [A]¹. [B]².[C]⁰ = 4 . r

The factor is 4.

e. By what factor does the reaction rate change if [C] is doubled (and the other reactant concentrations are held constant)?

If C is doubled, then:

r' = k. [A]¹. [B]².[2C]⁰ = 1. k. [A]¹. [B]².[C]⁰ = 1 . r

The factor is 1.

f. By what factor does the reaction rate change if the concentrations of all three reactants are doubled?

r' = k. [2A]¹. [2B]².[2C]⁰ = 2.4.1.k. [A]¹. [B]².[C]⁰ = 8 .r

The factor is 8.