An ideal gas is defined as a gas with no intermolecular forces of attraction. Ideal gases perfectly follow gas laws at all pressures and temperatures, while real gases only follow the laws at low pressures or high temperatures when the attractive forces between molecules are very small. This document discusses the differences between ideal and real gases and provides an example problem calculating the mass and volume of air removed from a high-altitude chamber when the pressure and temperature are reduced.

1. An ‘ideal gas’ is defined as a gas having no forces of intermolecular attraction.
The gases which follow the gas laws at all ranges of pressures and
temperatures are considered as “ideal gases”. However, ‘real gases’ follow
these laws at low pressures or high temperatures or both. This is because the
forces of attraction between molecules tend to be very small at reduced
pressures and elevated temperatures.

2. IDEAL GASES
Example The volume of a high-altitude chamber is 40 cubic meter. It is put
into operation by reducing pressure from 1 bar to 0.4 bar and temperature
from 25°C to 5°C.How many kg of air must be removed from the chamber
during the process ? Express thismass as a volume measured at 1 bar and
25°C.