Question

A 2 L flask contains 22 g of carbon dioxide and 1 g of helium at `20^(@)C` . Calculate the partial pressure exerted by `CO_(2)` and He if the total pressure is 3 atm.

Answer 1

Number of moles of `CO_(2)=("Weight of "CO_(2))/("Molecular Weight of "CO_(2))=22/44 = 0.5`.
Number of moles of He = `1/4 = 0.25`
Partial pressure = Mole fraction `xx` total pressure
`pco_(2) =(0.5)/(0.5+0.25) xx3=2`
`p_(He) =(0.25)/(0.75) xx 3 = 1` atm.