CHEM 177 SI
Chapter 10.2-10.10.7
4/22/2015
TINA AKINYI
1. Ar and He are both gases at room temperature. How do the average molecular velocities
(V) of their atoms compare at this temperature?
(A) VAr = 10VHe
(B) VHe = 3VAr
(C) VAr = 3VHe
2. Lithium reacts with water to produce hydrogen gas and lithium hydroxide. What volume
of hydrogen collected over water at 22˚C and 750 mm Hg pressure is produced by the
reaction of 0.208 g of Li? [VPH2O = 19.8 mm Hg]
(A) 367 mL
(B) 378 mL
(C) 735 mL
(D) 755 mL
3. A sample of a volatile liquid is introduced to an evacuated container with a movable
piston. Which change occurs as the piston is raised? (Assume some liquid remains.)
i) The fraction of the molecules in the gas phase increases
ii) The pressure in the container decreases
(A) I only
(B) II only
(C) Both I and II
(D) Neither I nor II
4. Compounds of uranium-235 and uranium-238 can be separated from one another by
(A) distillation.
(B) effusion.
(C) fractional crystallization.
(D) paper chromatography.
5. The average molecular velocity in a gas sample at 300 K is 500 m/s. The temperature of this
gas is increased until the average velocity of its molecules is 1000 m/s. What is the new
temperature?
(A) 420 K
(B) 573 K
(C) 600 K
(D) 1200K
6. Two samples of gas, one of argon and one of helium, have the same pressure, temperature
and volume. Which statement is true assuming both gases behave ideally?
(A) The helium sample contains more atoms than
the argon sample and the helium atoms have
a higher average speed.
(B) The two samples have the same number of
atoms but the helium atoms have a higher
average speed.
(C) The two samples have the same number of
atoms and both types of atoms have the
same average speed.
(D) The two samples have the same number of
atoms but the argon atoms have a higher
average speed.
7. A 12.0 g sample of gas occupies 19.2 L at STP. What is the molecular weight of this gas?
8. 5.600 g of solid CO2 is put in an empty sealed 4.00 L container at a temperature of 300 K.
When all the solid CO2 becomes gas, what will be the pressure in the container?
CHEM 177 SI
Chapter 10.2-10.10.7
4/22/2015
TINA AKINYI
9. A 1.25 mole sample of acetylene gas has a volume of 25 L at 25oC. What is the corrected
pressure according to van der Waal's?
a = 4.516 bar/L2mol * 100 kPa/bar = 451.6 kPa/L2mol
V = 25 L
b = 0.05220 L/mol
T = 25oC = 298.15 K
10. A 4.0 mole sample of nitromethane gas has a volume of 200 L at 27oC. What is the corrected
pressure according to van der Waal's?
a = 17.18 bar L2/mol X 100 kPa/bar = 1718.0 kPa L2/mol
V = 200 L
b = 0.1041 L/mol
T =27oC = 300.15 K