Re: gas in 325ml box has pressure of 695torr @19deg C How many mol of gas?

You are approaching the problem the right way.

PV = nRT
solving for n gives:  n = PV/RT

You have to convert each piece of data (volume, pressure, etc) into units that 
will cancel out to give you the number of moles.  I am not going to complete 
this step for you because it's just a matter of looking up the conversation 
factors and doing a bit of math.  But you are headed in the right direction.

Enjoy!

Kieran