AP Chemistry - 3.6: Deviation from the Ideal Gas Law

Requirements of an ideal gas?

1. Has molecule that take up no space

2. Has molecules with no inter-molecular attractions for each other

Do ideal gases exist in the real world?

No

What molecules can, under some circumstances, approximate ideal conditions.

Very small molecules

(He, H₂, Ne)

What conditions can allow gases to approximate ideal conditions?

1. High temperature (moving so fast attractions do not necessarily occur)

2. Low pressure (so far apart attractions do not necessarily occur)

What equation compensates for the different between real gases and ideal gases?

Van der Waals Equation

Van der Waals Equation

\left(P+\frac{n^2a}{V^2}\right)\left(V-nb\right)=nRT

What does (a) correct for in the Van der Waals Equation?

intermolecular forces

What does (b) correct for in the Van der Waals Equation?

size of particles themselves