A 5.00 L container of unknown gas at 25.0°C has a pressure of 2.45 atm. The mass of the gas is 32.1 g. What gas is in the container?

Question

Quizplus · Accepted Answer

We can use the ideal gas law, PV=nRT, to calculate the number of moles of gas present in the container:

n = (PV)/(RT) = (2.45 atm x 5.00 L) / (0.0821 L·atm/mol·K x 298 K) = 0.125 mol

Then, we can calculate the molar mass of the gas:

molar mass = mass/number of moles = 32.1 g / 0.125 mol = 256.8 g/mol

This molar mass is closest to that of sulfur dioxide (SO2), which has a molar mass of 64.06 g/mol. The molar mass of chlorine gas (Cl2) is 70.90 g/mol, fluorine gas (F2) is 37.99 g/mol, nitrogen gas (N2) is 28.02 g/mol, and oxygen gas (O2) is 32.00 g/mol. Therefore, the gas in the container is most likely sulfur dioxide (SO2).

A 500 L Container of Unknown Gas at 25