NAMES:

1) Argon (molar mass = 39.94 g mol^-1) and an unknown organic vapor are placed in a chamber at 0.5 atm each.  This chamber is separated from another chamber that has a detector in it for Ar only and a total pressure guage by a thin diaphram.  At a given time, a small hole is created in the diaphram and the gases leak (effuse) into the detection chamber.  Since the total pressure and the partial pressure of Ar are measured, then the pressure increase in the unknown is also known.  It was found by this technique that the Ar pressure build-up was 2.5 times faster than the unknown.  What is the molar mass of the unknown?
 
 
 
 
 
 
 
 
 
 
 

                                                                                                                              g mol^-1

2) How much faster does ²³⁵UF₆ diffuse compared to ²³⁸UF₆?  Give the answer to at least 4 significant figures.  
(The molar mass is known to at least 6 sif figs.)
 
 
 
 
 
 
 
 
 
 
 
 

                                                                    By a factor of:                                              .
                                        ( that is the ratio of v(235)/v(239) )