165 g of an unknown gas at 71 C and 110 atm is stored in a 2

1.65 g of an unknown gas at 71 °C and 1.10 atm is stored in a 2.45-L flask. What is density and molar mass of gas.

Solution

density = mass / volume
= 1.65 g/2.45 L
= 0.673 g/L

P = 1.1atm
T= 71.0 oC
= (71.0+273) K
= 344 K
density = 0.673 g/L
Lets derive the equation to be used
use:
p*V=n*R*T
p*V=(mass/molar mass)*R*T
p*molar mass=(mass/V)*R*T
p*molar mass=density*R*T

Put Values:
1.1 atm * MM = 0.673g/L * 0.08206 atm.L/mol.K *344.0 K
MM = 17.3 g/mol
Answer:
density = 0.673 g/L
Molar mass = 17.3 g/mol