Question

A 8.00 L tank at 11.3 °C is filled with 8.67 g of sulfur tetrafluoride gas and 16.4 g of dinitrogen difluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction of each gas. Be sure each of your answer entries has the correct number of significant digits. gas mole fraction xs ? sulfur tetrafluoride dinitrogen difluoride

Answer 1

gas	mole fraction
sulfur tetrafluoride	0.244
dinitrogen difluoride	0.756

Explanation

mass SF₄ = 8.67 g

moles SF₄ = (mass SF₄) / (molar mass SF₄)

moles SF₄ = (8.67 g) / (108.0586 g/mol)

moles SF₄ = 0.080234 mol

mass N₂F₂ = 16.4 g

moles N₂F₂ = (mass N₂F₂) / (molar mass N₂F₂)

moles N₂F₂ = (16.4 g) / (66.01 g/mol)

moles N₂F₂ = 0.24845 mol

Total moles = (moles SF₄) + (moles N₂F₂)

Total moles = (0.080234 mol) + (0.24845 mol)

Total moles = 0.32868 mol

mole fraction SF₄ = (moles SF₄) / (Total moles)

mole fraction SF₄ = (0.080234 mol) / (0.32868 mol)

mole fraction SF₄ = 0.244

mole fraction N₂F₂ = 1 - (mole fraction SF₄)

mole fraction N₂F₂ = 1 - (0.244)

mole fraction N₂F₂ = 0.756