Answers to Practice Gas Law Problems
1.
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3.
Calculate the density of carbon monoxide at STP.
Molar Mass of CO = 28.0 g/mol
MM=dRT/P
d=
so d = MM·P/RT
(28 g/mol)(1 atm)
(0.0821 L·atm/mol·K)(273K)
d = 1.25 g/L
4.
A 1.49-L sample of gas is collected over water at 60C and 95.4 kPa. What is the volume
of the dry gas at 799 mm Hg?
The water vapor pressure at 60ºC is 19.91 kPa (FROM THE TABLE!!!!!)
P1 = 95.4 kPa – 19.91 kPa 75.5 kPa
Convert P2 to kPa:
101.3 kPa 799 mm Hg = 106 kPa
760 mm Hg
P1V1 = P2V2
(75.5 kPa)(1.49 L) = (106 kPa)(V2)
1.06 L = V2
5.
50.0 mL of liquid methanol (CH3OH) is burned with 22.8 L of oxygen at 27C at a
pressure of 2.00 atm. The density of the methanol is 0.850 g/mL. Calculate the moles of
product(s) if the reaction goes to completion.