Question

A gaseous mixture of propylene and methylene fluoride, occupies a volume of 2.40L at 29°C. The partial pressure of `C_3H_6` is 0.130 atm and that of CH2F2 is 0.460 atm. How many moles of `C_3H_6` are in the sample? What is the total mass of the sample?

Answer 1

`n=(PV)/(RT)` for each sample.

Explanation:

Dalton's law of partial pressures states that in a gaseous mixture, the partial pressure exerted by a component is the same as it would exert if it alone occupied the container. The total pressure is the sum of the individual partial pressures.

So what does this mean? You can solve for `n` individually, and then use `n_"propane"` and `n_"methylene fluoride"` to determine the mass of each participant.

`n_"propane"` `=` `(0.130*atmxx2.40*L)/(0.0821*L*atm*K^-1*mol^-1xx302*K)` `=` `??mol.`

`n_"methylene fluoride"` `=` `(0.460*atmxx2.40*L)/(0.0821*L*atm*K^-1*mol^-1xx302*K)` `=` `??mol.`