Collected data: Mass of flask and foil (g): 61.0484 Mass of flask foil and conde
ID: 525397 • Letter: C
Question
Collected data:
Mass of flask and foil (g): 61.0484
Mass of flask foil and condensed vapor (g): 61.310
Temperature of boiling water bath: 100 C
Volume of flask (ml) : 148
Barometric pressure (mmHg): 763.6
Room temperature (C) : 22
Vapor Pressure at room temp (mmHg): 100
Calculations:
Corrected density of air at experimental conditions?
Initial mass of air in flask
final partial pressure of air in flask
final mass of air in flask
mass of air lost
corrected mass of condensed vapor
molecular weight of unknown liquid
Anything helps! Thank you!
Explanation / Answer
Mass of vapor in flask = (mass of flask, foil and condensed vapor) – (mass of flask and foil) = (61.310 g) – (61.0484 g) = 0.2616 g.
Final partial pressure of air in flask = (barometric pressure) – (vapor pressure of water at room temperature) = (763.6 mmHg) – (100 mmHg) = 663.6 mmHg = (663.6 mmHg)*(1 atm/760 mmHg) = 0.873 atm.
Temperature of boiling water bath = temperature of vapor = 100C = (100 + 273) K = 373 K
Volume of vapor in flask = 148 mL = (148 mL)*(1 L/1000 mL) = 0.148 L
Use the ideal gas law to find the number of moles of the gas.
P*V = n*R*T
===> n = P*V/RT = (0.873 atm)*(0.148 L)/(0.082 L-atm/mol.K).(373 K) = 0.004224 mole.
Molar mass of the liquid = molar mass of vapor = (mass of vapor)/(number of moles of vapor formed) = (02616 g)/(0.004224 mole) = 61.93 g/mol (ans).
I used the data which I thought will be relevant.