An ideal gas is a theoretical gas that is composed of randomly moving, non-interacting particles. The ideal gas concept completely obeys the ideal gas law, which approximates that behavior of gases under varying conditions.
Gases are said to act in the most ideal manner at high temperatures and low pressures. The ideal gas law is an equation with the formula PV = nRT, where P equals pressure, V equals the volume of the gas, n is the number of moles of gas present, R is the universal gas constant and T is the temperature. At high temperatures and low pressures, the volume of the gas becomes negligible, and the gas particles can move at high speeds. These behaviors are considered to be ideal.