A 1.75 L vessel contains 3.60 g of a gas at 1.25 atm and 31.0°C.

Question

1. Calculate the density of the gas in g/L
2. What is the molar mass of the gas? 

Answer 1

PV = nRT

P = 1.25 atm

V = 1.75 L

n = ? moles

R = 0.0821 Latm/Kmol'

T = 31C + 273 = 304K

Solving for n, we have...

n = PV/RT = (1.25)(1.75) / (0.0821)(304)

n = 0.08765 moles

1). density of the gas = 3.60 g / 1.75 L = 2.06 g / L

2). molar mass of the gas = 3.60 g / 0.08765 moles = 41.1 g / mole