Chemistry gas question?

Question

A 7.25 kg sample of xenon is stored in a high-pressure cylinder with a volume of 10.0 L at 28.5 C. What is the pressure using the ideal gas equation and the pressure using van der Waals equation. Also, in regards to van der Waals equation, is the correction for volume or the correction for intermolecular forces more important in this case? Please help

Answer 1

The van der Waals equation is an attempt to improve the ideal gas law by including repulsive and attractive molecular interactions and the non-zero volume taken up by the molecules themselves. The equation is

see site http://www.hull.ac.uk/php/chsajb/general/vanderwaals.html

where p is the pressure, V is the volume, n is the number of moles, R is the gas constant and T is the temperature as in the ideal gas law.

In the ideal gaw law, the gas particles are assumed not to interact and to have no size. In the van der Waals equation, built into the ideal gas law are The repulsive interactions and non-zero size of the molecules are taken into account by supposing that the molecules are only free to move in a volume V-nb where nb is approximately the volume occupied by the molecules themselves.

The pressure exerted by the gas on the walls of the container is related to the number and frequency of the collisions with the wall. These are both reduced by attractive forces between the molecules and this is included in the -a(n/V)2 term.

Xenon has few attractive forces since it is a noble gas without polarity, etc.

Ideal gas law is plug and chug: P=(nRT)/V

There is a van der Waal's calculator at the website, so you can plug in. Xenon is not there, but Argon is...

Answer 2

Use PV = nRT


first convert Xenon into moles... which is around 55.2 mol and convert temp to Kelvin

P (10) = (55.2)(.08206)(301.8)

P = 136.71 atm

forgot everything about van der waals... sorry...