IB Chemistry R2.2 R2.2.1
R2.2.1

Collision Theory & Rate

For a reaction to occur, particles must collide with sufficient energy (≥ activation energy, Ea) and correct orientation.

Rate of Reaction

\( \text{Rate} = \frac{\Delta[\text{concentration}]}{\Delta t} \)

Units: mol dm⁻³ s⁻¹. Rate is always positive.

Maxwell-Boltzmann Distribution

Kinetic Energy → Number of particles Lower T Higher T Ea Particles with E ≥ Ea can react

At higher temperature, the distribution shifts right and flattens — more particles have E ≥ Ea.

Think About It

The total area under both curves is the same. Why?

Because the total number of particles has not changed — only the distribution of their energies. The curve flattens and shifts right, but the area (total particles) remains constant.

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