Kinetics

A rate law describes

A rate law describes

the speed of a reaction at a given point in time and how it is affected by the concentration of the reactants.

An integrated rate law

• gives the change in concentration from time zero up to a given point

• can figure out concentration at specific time

when chemical is reacting,

the rate is constantly changing and is dropping

First order reaction

ln[A]t - ln[A]0 = -kt

Equations can be used to determine

• the concentration of a reactant remaining at any time after the reaction has started

• the time required for a given fraction of a sample to react

• the time required for a reactant concentration to reach a certain level

half life of first order reaction-integradted

t1/2 = ln2/k

second order integrated

1/[A]t - 1/[A]0 = kt

second order half life

t1/2 = 1/k[A]0

zero order reactions

[A]t - [A]0 = -kt

So difference between all 3

first = ln
second= reciprocal, no -kt

zero = template

Equation template

[A]t - [A]0 = ±kt

Arrhenius equation

k = Ae^(-Ea/RT)

Units of zero order rate constant

m/s

Units of first order rate constant

1/s

Units of second order rate constant

1/ms

Energy difference between reactants and transition state =

activation energy