Difference between ideal gas and real gas
For an ideal gas inter molecular collisions are assumed elastic, and van der walls forces are not factored into the ideal gas equation: PV=nRT.
Secondly, the volume taken up by the molecules of the gas are not taken into account whilst considering the overall volume of ideal gases.
An equation factoring in these properties is as follows: P= nRT/(V-nb) -n^2a/v whereby a and b are individual to each gas. This equation does actually form a cubic equation with respect to molar volume (normal volume/number of moles).
This cubic equation is as follows: PV^3 + V^2(Pb - RT) + aV - ab = 0
An Ideal gas obeys Boyle's Law, a real gas does not.
Boyle's Law states that the pressure of a gas is inversely proportional to its volume. This means for example that if you double the pressure of a gas it's volume will be exactly halved. Or if you triple the pressure of the gas it's volume will then be a third of the original volume. Only gases at very low pressure behave in a nearly ideal way. The graph of Pressure vs Volume for real gases is nonlinear. The behaviour or real gases can be expressed as a cubic equation of state. The van der Waals equation of state is the simplest of these cubic equations of state. Several others have been proposed that model the behaviour of real gases more accurately than the van der Waals equation of state.
Boyle's Law states that the pressure of a gas is inversely proportional to its volume. This means for example that if you double the pressure of a gas it's volume will be exactly halved. Or if you triple the pressure of the gas it's volume will then be a third of the original volume. Only gases at very low pressure behave in a nearly ideal way. The graph of Pressure vs Volume for real gases is nonlinear. The behaviour or real gases can be expressed as a cubic equation of state. The van der Waals equation of state is the simplest of these cubic equations of state. Several others have been proposed that model the behaviour of real gases more accurately than the van der Waals equation of state.
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