[suomi]

Hi,

I solved the following problem and here are my results:

Calculate the pressure of 1.00 mol of methane behaving as

a) an ideal gas
b) van der Waals gas

under both of the following set of conditions:
1) 298K and 10.0L
2) 502K in 102 mL

using R= 0.082058 L*atm*mol-1*K-1 i got:

ideal gas:
1) 2.45 atm
2) 404 atm

van der Waals gas:
1) 2.43 atm
2) 481 atm

My question is how I should compare and evaluate these results. My results don't seem to make sense to me,because I thought that a real gas would more likely to behave like an ideal gas with the increase in temperature. It seems that both values of ideal and v.d.W. gas are more close to each other at a lower temperature(298K) than at a high temperature (502K).

I would appreciate your help:)

[Cavillus]

Hi,

I solved the following problem and here are my results:

Calculate the pressure of 1.00 mol of methane behaving as

a) an ideal gas
b) van der Waals gas

under both of the following set of conditions:
1) 298K and 10.0L
2) 502K in 102 mL

using R= 0.082058 L*atm*mol-1*K-1 i got:

ideal gas:
1) 2.45 atm
2) 404 atm

van der Waals gas:
1) 2.43 atm
2) 481 atm

My question is how I should compare and evaluate these results. My results don't seem to make sense to me,because I thought that a real gas would more likely to behave like an ideal gas with the increase in temperature. It seems that both values of ideal and v.d.W. gas are more close to each other at a lower temperature(298K) than at a high temperature (502K).

I would appreciate your help:)

Well, the ideal gas model is supposed to be matching real gases at low P and high T.
Looking at the results you obtained, it's hard to claim a match when the pressure is 400-500 atm, even if the T is higher.
IMHO, the most important factor is pressure here, because it varies a lot in the two different situations.

[fledarmus]

Ask yourself these questions:

What are the assumptions underlying the ideal gas law?

Under what conditions are those assumptions valid?

If these conditions are not met, in what ways would the real gas differ from the ideal gas prediction?