# CfE: Antoine Equation

### Antoine Equation

Since the Clausius-Clapeyron equation assumes ideal gas behavior for the vapor it is not strictly accurate for all fluids.

An empirical relation is often used that exploits the same general form of equation ...

##### Definition:

The Antoine Equation is an empirical relation for the saturation pressure as a function of temperature that is loosely based on the Clausius-Clapeyron relation.

$\ln P = A - \frac{B}{C+T}$

##### Note:

The units on this equation make no sense, so we need to be careful with the constants A, B, and C.

##### Outcome:

Use the Antoine equation to relate T and P for pure species phase equilibrium

##### Outcome:

Explain the relationship between the Clausius-Clapeyron equation and the Antoine equation

##### Test:

Use the Antoine equation to prove that the normal boiling point of water (which is pretty non-ideal) is 100C.