# Question #5d452

##### 1 Answer

Mar 10, 2014

The Ideal Gas Law has a variation from the original or PV=nRT to

PM = dRT, where M is the molar mass in g/mol and d is the density.

To isolate M in the equation it can be rearranged to M = dRT/P

Plugging in values the equation would become

P = 1.00 atm

M = ???

d = 2.45 g/L

R = 0.0821 atm L / mol K

T = 20 C + 273 = 293 K

M = 2.45 g/L (0.0821 atm L /mol K) 293 K / 1.00 atm

The units that do not cancel are g/mol, providing an answer of

58.93 g/mol

I hope this was helpful.

SMARTERTEACHER