# What is the mass of oxygen occupying a vessel with a volume of 2.1 liters at a pressure of 300 kPa

**What is the mass of oxygen occupying a vessel with a volume of 2.1 liters at a pressure of 300 kPa and a temperature of 30 degrees. The molar mass of oxygen is 32 * 10 (-3) kg / mol.**

Answer: 8 g.

Solution: Mendeleev-Clapeyron equation:

p * V = n * R * T, where p is the pressure in Pa, V is the volume in m ^ 3, n is the amount of gas substance in moles, R is the universal gas constant (R = 8.31 J / (mol ∙ k )), T-temperature in Kelvin. We translate the values into the SI system: V = 2.1 / 1000 = 0.0021 m ^ 3, p = 300 * 1000 = 300000 Pa, T = 30 + 273 = 303 K. Substitute the values into the formula: n = p * V / R * T = (300000 * 0.0021) / (8.31 * 303) = 0.25 mol.

the mass of oxygen is calculated by the formula: m = n * M, M-molar mass: m = n * M = 0.25 * 0.032 = 0.008 kg = 8 g.