Answer:
Mole fraction SF₆: 0.119
Mole fraction CO₂: 0.881
Step-by-step explanation:
Mole fraction: Moles of gas / Total moles
Molar mass SF6: 146.0 g/m
Molar mass CO2: 44.0 g/m
Moles : mass / molar mass
Moles SF₆ : 8.79 g/ 146.0 g/m = 0.060 moles
Moles CO₂: 19.5 g / 44.0 g/m = 0.443 moles
Total moles: 0.060 moles + 0.443 moles = 0.503 moles
Mole fraction SF₆: 0.060 moles/0.503 moles = 0.119
Mole fraction CO₂: 0.443 moles/0.503 moles = 0.881
Sum of mole fraction every gas = 1