What is static equilibrium in chemistry?

Static equilibrium is a type of equilibrium in which the rates of the forward and reverse processes are zero.

We are all familiar with , in which the rates of opposing processes are equal.

Static equilibrium occurs when there is no exchange between reactants and products.

An example of static equilibrium is diamond turning into graphite.

##"C(diamond) ⇌ C(graphite)"##

Graphite is more stable than diamond, but the activation energy is so high that you must heat diamond to about 2000 °C before you'll see any diamond converting to graphite.

The estimates are that, at room temperature, the process will take millions or billions of years.

I can't wait that long, so, effectively, no diamond is being converted to graphite or vice versa.

The process is in static equilibrium.

If you have a reaction that can occur in only one direction, you can reach equilibrium once you have used up the .

Since the forward and reverse reactions stop occurring, you are at static equilibrium.

This defines the difference between dynamic and static equilibria.

In both cases, the rates of the forward and reverse reactions are the same.

The difference is: in static equilibrium, the rates of the forward and reverse reactions are zero.