AP Chemistry Kinetics

The shorter the half life

the higher the value of k (constant) is

half-lives for zero order

decrease (as shown by arrows)

Half lives for first order

remain constant

half lifes for second order

increase

Nuclear decay

Is an example of a first order reaction

Concetration vs. Time Graph of Zeroth Order

Concentration vs. Time Graph of First Order

Concentration vs. Time Graph of Second Order

Straight line plot to determine rate constant zeroth order

Straight line plot to determine rate constant first order

Straight line plot to determine rate constant second order

Relative rate vs. concentration of zeroth order

[A]t M   Rate1 M/S

1             1

2             1

3             1

Relative rate vs. concentration of First Order

[A]t M   Rate1 M/S

1             1

2             2

3             2

Relative rate vs. concentration of second order 

[A]t M   Rate1 M/S

1             1

2             4

3             9

half life for + unit k , rate constant for zeroth order

t12=[A]0/2k  + M/s

half life for + unit k, rate constant for 1st order

t12= 0.693/k + 1/s

half life for + unit k, rate constant for second order

t12= 1/k[A]0 + M 1-s1

1st order reactions always stay 

constant 

[A]t

the concentration at a time t (what we want to find)

[A]0

the initial concetration

k

rate constant

t

the time elapsed 

you can rearrange a formula to solve for

[A]t