What causes pressure in a closed container of gas?

1 Answer
Dec 11, 2016

Collisions between the gaseous molecules and the walls of the container, and collisions between the molecules.


At a molecular level, the gaseous particles impact the walls by collision, and the #"force per unit area"# exerted on the the container by the gas is the #"pressure"#.

Gas laws that relate pressure and temperature for a given volume or given quantity of gas, were perfected and rationalized very quickly, and it allowed early chemists and physicists to have a very shrewd idea of molecular properties, even though they had no way to measure the molecules (but for their macroscopic pressure, and temperature, and volume).