W3 Kinetics

Question 1

3 types of rate law

Answer 1

1. Rate of consumption/formation of specific reactant/product

A -> 2B

B is formed at twice the rate A is consumed

Rate of reaction of B: d[B]/dt

2. Differential rate law

Rate of reaction in terms of concentration = rate of formation/consumption divided by coeffient

Has same value no matter which product/reacted is used to calculate it

Rate of reaction: d[A]/dt = 0.5*(d[B]/dt)

3. Integrated rate law

Integrate the differential law on both sides to get concentration in terms of time. What you get depends on the reaction kinetics.

Question 2

Zero order reaction: rate law, integrated rate law

Answer 2

rate = k

Integrated rate law:

[A] = -kt + [A]₀

Question 3

First order reaction: rate law, integrated rate law

Answer 3

rate = k[A]

Integrated rate law:

ln[A] = –kt + ln[A]₀

Question 4

Second order reaction: rate law, integrated rate law

Answer 4

rate = k[A]2

Integrated rate law:

1/[A] = kt + 1/[A]₀

Question 5

Half life of zero order reaction

Answer 5

[A]₀/2k

Question 6

Half life of 1st order reaction

Answer 6

ln2/k

Question 7

Half life of 2nd order reaction

Answer 7

1/k[A]₀

Question 8

Arrhenius equation

Answer 8

k = rate constant

A = frequency factor

E_a = activation energy

R = gas constant

T = Kelvin temperature

Question 9

Arrhenius equation in graphable form

Answer 9

ln (natural log) to both sides

Question 10

Finding activation energy if 2 rate constants (at 2 temps) are given

Answer 10

Question 11

Steady state approximation

Answer 11

Assume that the concentration of any intermediates is constant - this usually only applies if concentration of intermediates is small

Sub this into the rate determining step to remove the intermediate from overall rate equation

Question 12

Michaelis-Menton equation

Answer 12