High school12 min

Rate laws, reaction orders and half-life

Recognise order 0, 1 or 2 from measurements, extract the rate constant and the half-life, and use the Arrhenius equation without unit traps.

The essentials

1

The rate law

v=k [A]n [B]mv = k\,[\mathrm{A}]^n\,[\mathrm{B}]^m kk: rate constant; nn and mm: partial orders; n+mn + m: overall order. Orders are found by experiment: they cannot be read off the coefficients of the equation, except for an elementary reaction.
2

First order — the one to know

Members only

3

Zero and second order

Members only

4

The unit of the rate constant

Members only

5

The Arrhenius equation

Members only

ƒWrite my own sheetOr start from a blank page: rewriting a concept in your own words is how it sticks.