3.6: Deviations from Ideal Gas Laws

Learning Objectives

I can explain the relationship among non-ideal behavior of gases, intermolecular forces and/or volumes.

Ideal Vs real Gases

Gases behave ideally under high temperature and low pressure.

Kinetic Molecular theory assumes that under these conditions of high T and low P, volumes of molecules are insignificant and too small compared to the distance separating them and that gases do not interact or have any intermolecular forces of any kind. This is assumed because gases under high temperature are moving quickly and under low pressure they are distant from each other and are not likely to interact with one another. However, not all gases behave ideally at high pressure (P>5 atm) and low temperature. We know that gases start to condense at low T and their IMF become more important.

Therefore, as pressure increases gases are pushed closer together which results in the volume of the gas becoming more significant.

As the temperature increases, gases start moving slower and the intermolecular forces start to become more significant.

Refer to the Jamboard on google classroom for more practice on this topic!