When does a real gas behave like an ideal gas?

A real gas behaves like an ideal gas under certain conditions. These conditions typically involve low pressure and high temperature. When the pressure is low and the temperature is high, the molecules of a real gas are far apart and have high kinetic energy, leading to minimal intermolecular interactions.

Under these conditions, the volume occupied by the gas molecules themselves becomes negligible compared to the total volume of the gas, and the effects of intermolecular forces (such as van der Waals forces) become less significant. As a result, the gas behaves more like an ideal gas, following the ideal gas law equation:

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PV=nRT

Where:

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P is the pressure of the gas,
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V is the volume of the gas,
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n is the number of moles of the gas,
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R is the ideal gas constant, and
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T is the temperature of the gas in Kelvin.
In summary, a real gas behaves like an ideal gas when its molecules are far apart and experience minimal intermolecular forces, which typically occurs at low pressure and high temperature.