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

  • Thread starter Thread starter requal
  • Start date Start date
  • Tags Tags
    Gas Van der waals
AI Thread Summary
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
Messages
6
Reaction score
0
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?
 
Chemistry news on Phys.org
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.
 

Thread 'Solubility of MgSO47H2O in water'

It seems like a simple enough question: what is the solubility of epsom salt in water at 20°C? A graph or table showing how it varies with temperature would be a bonus. But upon searching the internet I have been unable to determine this with confidence. Wikipedia gives the value of 113g/100ml. But other sources disagree and I can't find a definitive source for the information. I even asked chatgpt but it couldn't be sure either. I thought, naively, that this would be easy to look up without...
View full post »

Thread 'Why does having 8 valence electrons make an element inert?'

I was introduced to the Octet Rule recently and make me wonder, why does 8 valence electrons or a full p orbital always make an element inert? What is so special with a full p orbital? Like take Calcium for an example, its outer orbital is filled but its only the s orbital thats filled so its still reactive not so much as the Alkaline metals but still pretty reactive. Can someone explain it to me? Thanks!!
View full post »

Similar threads

About Van Der Waals interactions
Replies
2
Views
2K
Van der Waals' Forces and Hydrogen Bonding
Replies
2
Views
2K
Carbon atom larger than a water molecule? Measuring a molecule's size?
Replies
4
Views
6K
The van der Waals Equation: What is the exact meaning of 'volume of gas'?
Replies
5
Views
2K
Proof of second-order phase transition for a Van Der Waals Gas
Replies
6
Views
3K
Thermodynamics: Possible process between a van der Waals gas and an ideal gas
Replies
1
Views
1K
A I'm trying to follow the proof given in Box 5.3 of MCP (Thorne/Blandford)
Replies
4
Views
2K
Verifying properties of Van der Waals Gas
Replies
2
Views
1K
Does the Compressibility Factor of a Gas Relate to Van der Waals Constants?
Replies
1
Views
3K
Calculating Van Der Waals Forces: Gecko Climbing Walls
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top