A quantity of N2 occupies a volume of 1.5L at 300K and 1.2atm. The gas expands to a volume of 3.1L as the result of a change in both temperature and pressure.

Find the density of the gas at these new conditions.

Answer: 0.661g/L

Explanation:

T = 300K

P = 1.2atm

V = 1.5L

R = 0.082atm. L/K / mol

n = ?

From the ideal gas equation PV = nRT

n = PV / RT = (1.2x1.5) / (300x0.082)

n = 0.0732mol

Molar Mass of N2 = 28g/mol

Mass conc. = n x molar Mass

Mass conc = 0.0732 x 28

Mass conc of N2 = 2.0496g

Volume = 3.1L

Mass = 2.0496g

Density = ?

Density = Mass / volume

Density = 2.0496/3.1

Density = 0.661g/L