Question

A tank at is filled with of chlorine pentafluoride gas and of dinitrogen difluoride 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. chlorine pentafluoride mole fraction: partial pressure: dinitrogen difluoride mole fraction: partial pressure: Total pressure in tank:

Answer 1

A 8.00 L tank at 26.9 C is filled with 17.3 g of sulfur hexafluoride gas and 5.53 g of dinitrogen difluoride 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.

Answer: a) Mole fraction of sulfur hexafluoride = 0.59

Mole fraction of dinitrogen difluoride = 0.41

b) partial pressure of sulfur hexafluoride = 0.365 atm

partial pressure of dinitrogen difluoride = 0.254

c) Total pressure = 0.619atm

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$    

$\text{Moles of sulfur hexafluoride}=\frac{17.3g}{146g/mol}=0.118moles$

$\text{Moles of dinitrogen difluoride}=\frac{5.53g}{66g/mol}=0.083moles$

Total moles = 0.118 + 0.083 = 0.201

According to ideal gas equation:

$PV=nRT$

P = pressure of gas = ?

V = Volume of gas = 8.00 L

n = number of moles = 0.201

R = gas constant =$0.0821Latm/Kmol$

T = temperature =$26.9^0C=(26.9+273)K=299.9K$

$P=\frac{nRT}{V}$

$P=\frac{0.201\times 0.0820 Latm/Kmol\times 299.9K}{8.00L}=0.619atm$

$\text{Mole fraction of sulfur hexafluoride}=\frac{\text{Moles of sulfur hexafluoride}}{\text {Total moles}}=\frac{0.118}{0.201}=0.59$

$\text{Mole fraction of dinitrogen difluoride}=\frac{\text{Moles of dinitrogen difluoride}}{\text {Total moles}}=\frac{0.083}{0.201}=0.41$

$\text{partial pressure of sulfur hexafluoride}=\text {mole fraction}\times \text{total pressure}=0.59\times 0.619=0.365atm$

$\text{partial pressure of dinitrogen difluoride}=\text {mole fraction}\times \text{total pressure}=0.41\times 0.619=0.254atm$