You have a gas, one of the three known phosphorus–fluorine compounds (PF₃, PF₅, and P₂F₄). To find out which, you have decided to measure its molar mass.
(a) First, you determine that the density of the gas is 5.60 g/L at a pressure of 0.971 atm and a temperature of 18.2°C. Calculate the molar mass and identify the compound.
(b) To check the results from part (a), you decide to measure the molar mass based on the relative rates of effusion of the unknown gas and CO₂. You find that CO₂ effuses at a rate of 0.050 mol/min, whereas the unknown phosphorus fluoride effuses at a rate of 0.028 mol/min. Calculate the molar mass of the unknown gas based on these results.