# The cylinder with a capacity of 8 liters contains oxygen at a temperature of 30C and a pressure

**The cylinder with a capacity of 8 liters contains oxygen at a temperature of 30C and a pressure of 3 * 10 ^ 3Pa. Determine the mass of gas in the cylinder**

V = 8 l = 0.008 m3.

t = 30 ° C.

P = 3 * 103 Pa.

M = 0.032 kg / mol.

R = 8.31 m2 * kg / s2 * K * mol.

m -?

Let us write down the Mendeleev-Cliperon law for oxygen: P * V = m * R * T / M, where m is the mass of oxygen, R is the universal gas constant, T is the absolute temperature of oxygen, M is the molar mass, P is the gas pressure, V is the volume that the gas occupies.

m = P * V * M / R * T.

We find the absolute temperature by the formula: T = 273 + t.

T = 273 + 30 ° C = 303 ° K.

m = 3 * 10 ^ 3 P * 0.008 m3 * 0.032 kg / mol / 8.31 m2 * kg / s2 * K * mol * 303 ° K = 0.0003 kg.

Answer: the cylinder contains m = 0.0003 kg of oxygen.