CHEM 177 SI
Chapter 10.2-10.10.7
11/18/2015
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. 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
3. Compounds of uranium-235 and uranium-238 can be separated from one another by
(A) Distillation.
(B) Effusion.
(C) Fractional crystallization.
(D) Paper chromatography.
4. 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
5. 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.
6. 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? Assume the
temperature is constant, and the volume of the container doesn’t change.