Question

Explain the rate of reaction

\[\ce{2N2O5 -> 4NO2 + O2}\]

using 

1. concentration change of N₂O₅,
2. concentration change of O₂.

Answer 1

For the reaction

\[\ce{2N2O5 -> 4NO2 + O2}\]

The rate of reaction is defined in terms of the change in concentration of reactants or products per unit time, divided by their stoichiometric coefficients.

Rate using the concentration of N₂O₅:

\[\ce{Rate = -\frac{1}{2} * \frac{d[N_2O_5]}{dt}}\]

The negative sign indicates that the concentration of N₂O₅ decreases with time.

Rate using the concentration of O₂:

\[\ce{Rate = \frac{d[O_2]}{dt}}\]

No coefficient division is needed for O₂ here because its stoichiometric coefficient is 1.

∴ The rate of the reaction can be expressed as

\[\ce{Rate = -\frac{1}{2} * \frac{d[N_2O_5]}{dt} = \frac{d[O_2]}{dt}}\]

This expression shows that the rate is proportional to the disappearance of N₂O₅ and the formation of O₂.