Question

Calculating mole fraction in a gas mixture A8.00 L tank at 24.0 °C is filled with 18.2 g of sulfur tetrafluoride gas and 7.54 g of boron trifluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction of each gas. Round each of your answers to 3 significant digits. mole fraction X 5 ? sulfur tetrafluoride boron t oride

Answer 1

Molar mass of SF4,

MM = 1*MM(S) + 4*MM(F)

= 1*32.07 + 4*19.0

= 108.07 g/mol

Molar mass of BF3,

MM = 1*MM(B) + 3*MM(F)

= 1*10.81 + 3*19.0

= 67.81 g/mol

n(SF4) = mass/molar mass

= 18.2/108.07

= 0.1684

n(BF3) = mass/molar mass

= 7.54/67.81

= 0.1112

n(SF4),n1 = 0.1684 mol

n(BF3),n2 = 0.1112 mol

Total number of mol = n1+n2

= 0.1684 + 0.1112

= 0.2796 mol

Mole fraction of each components are

X(SF4) = n1/total mol

= 0.1684/0.2796

= 0.6023

X(BF3) = n2/total mol

= 0.1112/0.2796

= 0.3977

Answer:

0.602

0.398