Question

A 9.0 L tank at 2.14 degrees C is filled with 5.18g of carbon monoxide gas and 12.1g of boron trifluoride gas. You can assume both gases behave as ideal gases under these conditions.

Calculate the mole fraction and partial pressure of each gas, and the total pressure in the tank. Be sure your answers have the correct number of significant digits.

Answer 1

moles of CO = 5.18 / 28 = 0.185

moles of BF3 = 12.1 / 67.8 = 0.178

total moles = 0.185 + 0.1785 = 0.3635

P V = n R T

P x 9 = 0.3635 x 0.0821 x 275.29

Ptotal = 0.913 atm

partial pressure of CO = mole fraction x Ptotal

                                    = (0.185 / 0.3635) x 0.913

partial pressure of CO = 0.465 atm

partial pressure of BF3 = (0.1785 / 0.3635) x 0.913

partial pressure of BF3 = 0.448 atm