Reactivity 2.2 - Arrhenius Equation

You're at a party, and the room is filled with dancing molecules (stay with me here). Every once in a while, two molecules will bump into each other with enough energy to start a chemical reaction. But not every bump leads to a reaction; some are just friendly nudges, while others are full-blown collisions!

This party scenario is essentially how reactions happen: molecules need to have enough energy when they collide to overcome a barrier, kind of like a velvet rope at a VIP section. This energy barrier is called the "activation energy".

Now, imagine turning up the heat at the party (quite literally). The room gets hotter, and the dancing molecules move faster. With more speed and energy, they're more likely to collide and overcome that VIP rope, leading to more reactions.

This is where the Arrhenius equation comes in:



  • k is the reaction rate (how quickly the reaction happens).
  • A is the pre-exponential factor (think of it as the total number of molecules at the party).
  • Ea is the activation energy (the height of the velvet rope).
  • R is the universal gas constant.
  • T is the temperature (how hot the party is).

The most compelling part of this equation is the exponential term, e−EaRT. This term shows that even a small increase in temperature (T) can lead to a significant increase in the reaction rate.

In summary:

The Arrhenius equation is like the mathematics of a molecular party. It tells us how temperature affects the likelihood of reactions taking place. By understanding it, we get an insight into why some reactions happen quickly at high temperatures, and others don't. And the next time you're at a party, you'll look at the dance floor a bit differently!