t 013 points Previous Answers FOLLOW-UP PROBLM 5.9 Applying Dalton\'s Law of Par
ID: 540958 • Letter: T
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t 013 points Previous Answers FOLLOW-UP PROBLM 5.9 Applying Dalton's Law of Partial Pressures To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. A chemical engineer places a mixture of noble gases consisting of 5.30 g of He, 14.9 g of Ne, and 35.4 g of Kr in a piston-cylinder assembly at STP. Calculate the partial pressure of each gas. Phe- 11 13.92 Your response differs from the correct answer by more than 100%, atm Phe2.20 Your response differs from the correct answer by more than 100%, atm Pk 2615x Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. atm Submit Answer 4 pointsExplanation / Answer
A tank contains 5.30 g He, 14.9 g Ne and 35.4 g Kr
At STP pressure is 1 atm.
Calculate the moles of each gas in piston cylinder by dividing their molar mass
Molar mass of He =4.002602 g/mol
Moles of He = 5.30 g/4.002602 g/mol = 1.324 moles
Molar mass of Ne = 20.1797 g/mol
Moles of Ne are in the tank = 14.9 g/20.1797 = 0.738 moles
Molar mass of Kr = 83.798 g/mol
Moles of Kr in the tank = 35.4/83.798 = 0.422 moles
Total moles of gas in piston cylinder = 1.324 moles + 0.738 moles +0.422 moles = 2.484 moles
Calculate the moles fraction of each gas in piston cylinder
Mole fraction of He = 1.324 moles/2.484 moles = 0.533
Mole fraction of Ne = 0.738/2.484 = 0.297
Mole fraction of Kr = 0.422 moles/2.484 = 0.170
Dalton's law for can be rearranged to give the partial pressure of a gas in a mixture in terms of the mole fraction of gas.
Partial pressure of gas = Mole fraction x total pressure.
So,
Partial pressure of He = 0.533 x 1atm = 0.533 atm.
Partial pressure of Ne = 0.297 x 1 atm. = 0.297 atm.
Partial pressure of Kr = 0.170 x 1 atm. = 0.170 atm.
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