objective Knowledge Check Question 7 A 700L tank at 203 C is

objective Knowledge Check Question 7 A 7.00L tank at 20.3 °C is filled with 2.74 g of carbon dioxide gas and 18.7 g of chlorine pentafluoride 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. mole fraction: carbon dioxide partial pressure mole fraction: chlorine pentafluoride partial pressure 0am Total pressure in tank

Solution

atomic weights : C= 12.0107 g/mole, O= 15.9994, Cl=35.453, F= 18.9984032

molar mass of CO2= 12.0107+2*15.9994 =44.0095 and that of Chlorine pentafluoride (ClF5)= 35.453+5*18.9984032=130.44 g/mole

moles= mass/molar mass

moles : CO2= 2.74/44.0095=0.06248, ClF5= 18.7/130.44 =0.1434

total moles of mixture, n = 0.06248+0.1434 =0.20588

mole fraction = moles of component/total moles

mole fraction : CO2= 0.06248/0.20588= 0.3034, ClF5=1-0.3034= 0.6966

total pressure from gas law, PV= nRT, P= nRT/V= 0.20588*0.0821*(20.3+273)/7=0.708 atm

partial pressure = mole fraction* total pressure , partial pressure: CO2=0.3034*0.708=0.215 atm and that of ClF5= 0.708-0.215= 0.493 atm