Question

Four gases were combined in a gas cylinder with these partial pressures: 3.5 atm N2, 2.8 atm O2, 0.25 atm Ar, and 0.15 atm He.

Answer 1

Answer:

Mole fraction of $O_{2}$ = 0.42

Moles fraction of Ar = 0.037

Explanation:

Let's assume all the four gases and their mixture behave ideally.

According to Dalton's law of partial pressure for mixture of ideal gases-

                                    $P_{i}=x_{i}P_{total}$

where $P_{i}$ and $x_{i}$ are partial pressure and mole fraction of "i"-th gas respectively. $P_{total}$ is total pressure of gaseous mixture.

Here $P_{total}$ = $P_{N_{2}}+P_{O_{2}}+P_{Ar}+P_{He}$

                  = (3.5+2.8+0.25+0.15) atm

                   = 6.7 atm

So $x_{O_{2}}=\frac{P_{O_{2}}}{P_{total}}$  =  $\frac{2.8atm}{6.7atm}$  = 0.42

    $x_{Ar}=\frac{P_{Ar}}{P_{total}}$  = $\frac{0.25atm}{6.7atm}$  = 0.037