The cylinder contains oxygen at a temperature of 290 K and a pressure of 1.5 • 10 ^ 5 Pa.

The cylinder contains oxygen at a temperature of 290 K and a pressure of 1.5 • 10 ^ 5 Pa. Oxygen mass 13 kg. What is the density of oxygen in the vessel?

Solution: let’s use the Clapeyron – Mendeleev equation:
p⋅V = mM⋅R⋅T, where
p = 1.5 * 10 to the 5th degree Pa-oxygen pressure;
V-volume of oxygen;
M = 0.032 kg \ mol-molar mass of oxygen;
R = 8.31 J / (mol ∙ K) – universal gas constant;
T = 290K-gas temperature;
ρ = m / V;
ρ = p⋅M / R⋅T = 1.5 * 10 to the 5th degree * 0.032 / 8.31 * 290 = 1.99 kg / m3