[steve569]

What equation would i use for this problem? what are partial pressures and mol percents??:

The total pressure of a mixture of 5.0g of argon, 5.0g of xenon, and 5.0g of krypton is 134.9 kPa. what are the mol percents and partial pressures of each of the gases?

[Borek]

Just definitions.

[pizza1512]

Well I just looked up the first definition on Wikipedia: 

Partial pressure is the pressure which the gas would have if it alone occupied the volume.

I would have thought that 'mols percent' is another definition for the concentration of something like when we use mols / dm³ for aqueous solutions.  So it is probably the number of moles you would expect to find in 100 cm³ of air.  I am not actually quite sure; this was only a suggestion.

A useful formula to know for this question is that 1 mol of any gas occupies 24 dm³ of space.

[DevaDevil]

Well I just looked up the first definition on Wikipedia: 

Partial pressure is the pressure which the gas would have if it alone occupied the volume.

So it is probably the number of moles you would expect to find in 100 cm³ of air.  I am not actually quite sure; this was only a suggestion.

ok: partial pressure's definition is right, but a bit troublesome formulated.
Say if you have 1 mol gas A and 2 mol gas B in a volume V at 3 atm, then the partial pressure of A would be 1 atm, because if the same amount of A as in that mixture (1/3 of the total moles present) would occupy the same volume (V) as that original mixture, it would have a pressure of 1/3 * 3 = 1 atm.

A useful formula to know for this question is that 1 mol of any gas occupies 24 dm3 of space.

Only at standard temperature and pressure.
However, for this question as originally posted by steve, the gaslaw is not needed, only the molar weights of the gases.

[justin122289]

To find the mole percents, you would have to first change all of the given masses to moles (using the molar masses). Then to find the mole percent of a specific gas, take the moles of the gas and divide it by the total moles of the system. That gives you a decimal, so multiply by 100 to get the percent. As for the partial pressures, I'd have to do a little more research to help you out there.

[DevaDevil]

To find the mole percents, you would have to first change all of the given masses to moles (using the molar masses). Then to find the mole percent of a specific gas, take the moles of the gas and divide it by the total moles of the system. That gives you a decimal, so multiply by 100 to get the percent. As for the partial pressures, I'd have to do a little more research to help you out there.

as long as we are gonna do a walkthrough anyway:

partial pressure is molar fraction multiplied by total pressure of the gases.

[Borek]

as long as we are gonna do a walkthrough anyway:

partial pressure is molar fraction multiplied by total pressure of the gases.

Told ya to use definition