Ideal Gas Law Questions!

What is the molar mass of Freon-11 gas if its density is 6.13 g/L at 273K and 1 atm?

a. 0.274 g/mol

b. 3.64 g/mol

c. 78.2 g/mol

d. 137 g/mol

e. 365 g/mol

Just assume you have 1.0 L of it at standard conditions. Then

n = v / V, where v = 1.0 L, V = 22.4 L/mol

n = 1.0 L / 22.4 L/mol = 0.04464 moles

Now you also know that

n = m / M therefore:

M = m / n

The mass of 1.0 L is 6.13 g

So the Molar mass will be 6.13 g / 0.04464 mol or 137 g/mol

22.4 liters/mole at STP x 6.13 grams/liter = 137.3

option D.