# How are real gases different from ideal gases?

May 27, 2017

Many ways

#### Explanation:

There are a few assumptions made with ideal gases:

• Elastic collision occurs between ideal gas molecules
• Ideal gas molecules do not possess potential energy, i.e. they are not affected by intermolecular forces
• The volume of ideal gas molecules is negligible compared to the volume of the container
• The ideal gas molecules are spherical in shape
• The ideal gas molecules are all identical

Hence, intuitively deducing, real gases differ from ideal gases in the sense that:

• Real gas molecules do inelastic collisions
• Real gas molecules possess potential energy, i.e. they are affected by intermolecular forces
• The volume of real gas molecules is NOT negligible
• The real gas molecules are not spherical in shape
• The real gas molecules are not all identical
May 27, 2017

I tried this:

#### Explanation:

The molecules of an ideal gas are treated as point molecules with volume equal to zero that is not really always realistic. Also there are no interactions (chemical) between molecules and if they undergo a collision it will be perfectly elastic. This is difficult because it is possible or realistic for molecules to interact with each other either through chemical interactions (bonding) or exchange of energy during collisions.

You can see that we will need to include, for a real gas, in $P V = n R T$ for example, at least a correction factor for the volume to take into account the volume of the molecules and a correction factor for the pressure to take into account the exchanges of energy during impacts.