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Mass of empty flask and cover: 120.02 Mass of flask/cover/vapor: 120.76 Temperat

ID: 878058 • Letter: M

Question

Mass of empty flask and cover: 120.02

Mass of flask/cover/vapor: 120.76

Temperature of vapor, in Celsius: 95.0 degrees Celsius

Temperature of vapor, Kelvin: 368 K

Pressure of vapor, mm Hg: 754.9 mm Hg

Pressure of vapor, atm: 0.9933 atm

Mass of flask/cover with water, grams: 277.91 g

Temperature of water in flask, degrees Celsius: 26 degrees Celsius

Density of water at this temperature, g/mL: 0.99681 g/mL

Volume of flask: 282 mL

Moles of vapor in flask: 0.00927 mol

-What is the molar mass of vapor?

Explanation / Answer

Molar mass of sample= mass of sample/ moles of sample

Mass of vapor = 120.76-120.02= 0.74 gms

Volume of flask at STP = 225*(0.9933/1)273/368=165.79ml =0.166 liter

1 gmole occupies 22.4 liters

0.165 liters corresponds to =0.166/22.4 =0.007411 moles

Molar mass= mass/ moles= 0.74/0.007411=99.95 g/mol