Ideal gas problem- pV=nRT?

Question

Find the molecular weight of a gas of which 5.03 g occupies a volume of 4.4L when the pressure is 1.333 atm and the temperature 65.5 degrees Celcius.

Answer 1

pV=nRT

where

P is the absolute pressure [Pa],
Vis the volume [m3],
n is the amount of substance of gas [mol],
R is the gas constant [8.314 472 m3·Pa·K−1·mol−1],
T is the temperature in kelvin [K].
4.4 L = 0.0044 cubic meters
65.5 degrees Celsius = 338.65 kelvin
1.33300 atm = 135066.225 pascal

135066.225 * 0.0044 cubic meters = n * 8.314 * 338.65
n = 135066.225 * 0.0044 / 8.314 * 338.65
n = (135066.225 * 0.0044) / (8.31400 * 338.65) = (135 066.225 * 0.0044) / (8.31400 * 338.65) = 0.211075749 moles

5.03 / 0.211075749 = 23.8303075 grams / mole

Answer 2

You have to convert:
temperature to Kelvin
volume to cubic metres
atm to Pascals

and then you can use n = pV/RT

and then Mr = mass/n

Answer 3

Convert Temp to Kelvin and solve for n (number of moles). Because molecular weight is g/mol, take your grams and divide it by how many moles you have to get g/mol.