Is the Van der Waals Gas Equation More Accurate Than the Ideal Gas Equation?

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In the discussion about the van der Waals equation, it is clarified that the real pressure of a gas is lower than the ideal pressure, and the real volume can be less than the ideal volume under certain conditions. The confusion arises when considering how real volume could be perceived as larger than ideal volume. The ideal gas law does not account for the volume occupied by gas molecules, leading to the misconception that real volume should always be less at high pressures. However, at high pressures, the volume occupied by gas molecules becomes significant, resulting in a real volume that is greater than what the ideal gas law predicts. This highlights the limitations of the ideal gas model, particularly in scenarios where molecular size and interactions cannot be ignored.
requal
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Just wondering, for van der waals equation, the real pressure is smaller than the ideal pressure and the real volume is smaller than the ideal volume?
 
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Check - calculate P&V for several cases using both ideal gas equation and VdV equation.
 
Okay I found out that the real volume is indeed less than the ideal volume, but I don't get how the real volume is bigger than the ideal volume? I thought it would be the other way around because molecular volume becomes significant at high pressures meaning that gases have less free space to move around (because some of the space is taken up by the gas molecules themselves), and hence the real volume would be lower than the ideal volume? No?
 
requal said:
Okay I found out that the real volume is indeed less than the ideal volume, but I don't get how the real volume is bigger than the ideal volume?

This is a little bit convoluted and I have a feeling you are contradicting yourself - volume is less but you don't understand how it is bigger?

Ideal gas ignores molecule size, so at high pressures it theoretically compresses to zero, real volume is much larger than that.
 

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