Temperature and activation energy · ⁨温度和活化能⁩

Why heat speeds things up

• The activation energy 活化能 ($E_A$) is the minimum energy a collision needs to be effective.
• The Boltzmann distribution 玻尔兹曼分布 shows how molecular energies are spread out.
• Raising the temperature gives a big rise in rate.

The Boltzmann distribution

• The curve starts at the origin, peaks, then falls in a long tail. The area under it is the total number of molecules.
• Only molecules to the right of $E_A$ have enough energy to react.

Why temperature matters

• Raising the temperature spreads the curve to the right, so a much larger fraction of molecules now exceed $E_A$.
• Molecules also collide more often — but the first effect is the bigger one.
• That's why a small rise in temperature gives a large rise in rate.

A collision only reacts with the right orientation and enough energy

The Boltzmann picture

• Raising temperature shifts the Boltzmann distribution, so far more molecules exceed the activation energy.
• This is why a small temperature rise can roughly double the rate.

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