Why do spontaneous processes increase entropy?

1 Answer
Apr 8, 2014

First of all, take a look at this picture:

A reaction is said to be spontaneous if it occurs without being driven by some outside force.

There are two driving forces for all chemical reactions. The first is enthalpy, and the second is entropy.

Since your question is about entropy I'm continuing with it.

Entropy is a measure of the disorder of a system, and systems tend to favor a more disordered system (remember this!). Nature tends toward chaos. Funny, isn't it. Spontaneous reactions occur without outside intervention (force).

Back to the picture: when you mix two things (solute and solvent) you always get a solution. You can't get a solution where you have solvent on one side and solute on the other. It also tends toward chaos, right?

To conclude: spontaneous processes increase entropy!