molar mass= grams/ moles
the grams are already given 65.18 grams. we have to find the moles to get the molar mass using the ideal gas law formula
ideal gas law---> PV= nRT
P=2.25 atm
V= 4.81 Liters
R= 0.0821 atm·L/ mol·K
T= 350 K
n= moles ???
we can rearrange the formula to solve for moles.
n= PV/RT
n= (2.25 x 4.81) / (0.0821 x 350 K)= 0.377 moles
molar mass= 65.18 grams/ 0.377 moles= 173 g/mol