5 Steps to a 5 AP Chemistry

7.A reaction produces a gaseous mixture of carbon

dioxide, carbon monoxide, and water vapor.

After one reaction, the mixture was analyzed and

found to contain 0.60 mol of carbon dioxide,

0.30 mol of carbon monoxide, and 0.10 mol of

water vapor. If the total pressure of the mixture

was 0.80 atm, what was the partial pressure of

the carbon monoxide?

(A) 0.080 atm

(B) 0.34 atm

(C) 0.13 atm

(D) 0.24 atm

(E) 0.48 atm

8.A sample of methane gas was collected over

water at 35°C. The sample was found to have a

total pressure of 756 mm Hg. Determine the

partial pressure of the methane gas in the sample

(vapor pressure of water at 35°C is 41 mm Hg).

(A) 760 mm Hg

(B) 41 mm Hg

(C) 715 mm Hg

(D) 797 mm Hg

(E) 756 mm Hg

9.A sample of oxygen gas with a volume of 8.00 L

at 127°C and 775 mm Hg is heated until it

expands to a volume of 20.00 L. Determine the

final temperature of the oxygen gas, if the pres-

sure remains constant.

(A) 727°C

(B) 318°C

(C) 1000°C

(D) 160°C

(E) 45°C

10.The average kinetic energy of nitrogen molecules
changes by what factor when the temperature is
increased from 30°C to 60°C?

(A) (333 – 303)

(B) 2

(C)^1 ⁄ 2

(D)

(E) 28

11.A 1.15-mol sample of carbon monoxide gas has a

temperature of 27°C and a pressure of 0.300 atm.

If the temperature is lowered to 17°C, at constant

volume, what would be the new pressure?

(A) 0.290 atm

(B) 0.519 atm

(C) 0.206 atm

(D) 0.338 atm

(E) 0.310 atm

12.An ideal gas sample weighing 1.28 grams at

127 °C and 1.00 atm has a volume of 0.250 L.

Determine the molar mass of the gas.

(A) 322 g/mol

(B) 168 g/mol

(C) 0.00621 g/mol

(D) 80.5 g/mol

(E) 49.4 g/mol

13.Increasing the temperature of an ideal gas from

50 °C to 75°C at constant volume will cause

which of the following to increase for the gas?

I. the average distance between the molecules

II. the average speed of the molecules

III. the average molecular mass of the gas

(A) III only

(B) I only

(C) II only

(D) II and III

(E) I and II

14.If a sample of CH 4 effuses at a rate of 9.0 mol

per hour at 35°C, which of the gases below will

effuse at approximately twice the rate under the

same conditions?

(A) CO

(B) He

(C) O 2

(D) F 2

(E) SiH 4

303 333−

Gases  115