Air has an average molar mass of 29.0 g/mol. The density of air at 1.00 atm and 30°C is

Question

Quizplus · Accepted Answer

We can use the ideal gas law, PV = nRT, to find the density of air at 1.00 atm and 30°C. First, we need to find the number of moles of air present in 1.00 L of air at these conditions.

n = (PV)/(RT) 
n = (1.00 atm)(1.00 L) / [(0.08206 L·atm/K·mol)(303 K)]
n ≈ 0.038 mol

Next, we can use the molar mass of air to find the mass of 0.038 mol of air.

mass = n × molar mass 
mass = (0.038 mol)(29.0 g/mol) 
mass ≈ 1.10 g

Finally, we can divide the mass by the volume to find the density.

density = mass/volume 
density = 1.10 g / 1.00 L 
density = 1.10 g/L

Therefore, the best choice is B: 1.17 g/L.

Air Has an Average Molar Mass of 29