Why does the ideal gas state equation fail at high pressures for real gases?

In summary, the ideal gas state equation, PV = nRT, fails at high pressures for real gases due to the effects of intermolecular forces and the finite size of gas molecules. These factors cause deviations from ideal gas behavior and result in lower volumes and pressures than predicted by the equation. The equation should only be used at low pressures and high temperatures, where these effects are negligible. Other factors that can contribute to the failure of the equation at high pressures include non-ideal behavior, such as chemical reactions and phase changes.
  • #1
Bugsy23
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Why does the ideal gas state equation fail at high pressures for real gases? I think it has something to do with the forces between the molecules in the gas, but I'm not sure the exact reason
 
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  • #2
It has to do with the compressibility of non-ideal gases which is due to some extent to the forces between molecules.

For really high pressures it also has to do with quantum effects due to the properties of indistinguishable particles and the Pauli exclusion principle.
 

1. Why does the ideal gas state equation fail at high pressures for real gases?

The ideal gas state equation, PV = nRT, assumes that gas molecules have no volume and do not interact with each other. However, at high pressures, the volume of gas molecules becomes significant and the attractive forces between molecules start to affect their behavior. This leads to deviations from the ideal gas behavior and the failure of the ideal gas state equation.

2. What is the effect of intermolecular forces on the ideal gas state equation?

Intermolecular forces, such as London dispersion forces and dipole-dipole interactions, become more significant at high pressures. These forces cause gas molecules to attract each other and take up space, leading to a decrease in the volume available for the gas molecules to move around. This results in a decrease in pressure, which is not accounted for in the ideal gas state equation.

3. Can the ideal gas state equation be used at all pressures?

No, the ideal gas state equation is only valid at low pressures and high temperatures, where the volume and intermolecular forces of gas molecules are negligible. At high pressures, the equation fails to accurately predict the behavior of real gases and should not be used.

4. How do real gases deviate from ideal gas behavior at high pressures?

At high pressures, real gases deviate from ideal gas behavior by exhibiting lower volumes and lower pressures than predicted by the ideal gas state equation. This is due to the effects of intermolecular forces and the finite size of gas molecules, which are not taken into account by the ideal gas state equation.

5. Are there any other factors that can cause the failure of the ideal gas state equation at high pressures?

In addition to intermolecular forces, real gases can also deviate from ideal gas behavior at high pressures due to non-ideal behavior, such as chemical reactions between gas molecules or phase changes. These factors can also affect the volume and pressure of gas molecules and lead to deviations from the ideal gas state equation.

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