Rate of reaction = change in amount of reactant used or product formed ÷ time taken
Rate of reaction = Δconcentration ÷ Δtime
Rate of reaction = Δmass ÷ Δtime
Rate of reaction = Δvolume of gas ÷ Δtime
Rate of reaction = Δmoles ÷ Δtime
Rate of reaction = (final value – initial value) ÷ time
For reactants, rate = decrease in concentration ÷ time
For products, rate = increase in concentration ÷ time
Units can be mol dm⁻³ s⁻¹, g s⁻¹, cm³ s⁻¹, or mol s⁻¹
Average rate = total change ÷ total time
Instantaneous rate = gradient of a tangent on a graph
Steeper graph slope = faster rate
Flat graph slope = slower or zero rate