Calculating reaction rates
For aA + bB 
cC + dD
A, B, C and D are substances.
a, b, c and d are coefficients.
Δ[A] is read change in concentration of A and equals the final - initial concentrations of A.
As reaction rates must always be positive, rate is calculated using the negative of a change in concentration of a reactant.
The relative rates of appearance and disappearance of various reactants and products depends on their coefficient in the balanced equation. Thus the reaction rate is calculated by dividing the change in concentration of that substance by the coefficient associated with that substance in the balanced equation for the reaction.
The unit associated with reaction rate is concentration per unit time.
If concentration is measured in and time in seconds, rate has the unit s–1.
cC + dDA, B, C and D are substances.
a, b, c and d are coefficients.
| reaction rate = | –Δ[A] | = | –Δ[B] | = | Δ[C] | = | Δ[D] |
| a × Δt | b × Δt | c × Δt | d× Δt |
Δ[A] is read change in concentration of A and equals the final - initial concentrations of A.
As reaction rates must always be positive, rate is calculated using the negative of a change in concentration of a reactant.
The relative rates of appearance and disappearance of various reactants and products depends on their coefficient in the balanced equation. Thus the reaction rate is calculated by dividing the change in concentration of that substance by the coefficient associated with that substance in the balanced equation for the reaction.
The unit associated with reaction rate is concentration per unit time.
If concentration is measured in and time in seconds, rate has the unit s–1.