Physical Chemistry 1 Prob Set

Mata, Arrianne Jaye N. Prof. Eric RoqueBS CHE301/ Monday (2:00-5:00 pm) Physical Chemistry 1

Physical Chemistry 1 Problem Set

Boyle’s Law – Pressure-Volume Relationship

1. The pressure of 200 mL of a gas at constant temperature is changed from 380 torr to 760 torr. The new volume of the gas is?

a. 100 mL b. 200 mL

c. 300 mL d. 400 mL

2. A sample of gas occupies a volume of 225 mL at a pressure of 720.0 torr and a temperature of 20.0 °C. Calculate the new pressure if the volume is increased to 350.0 mL, at constant temperature.

a. 163 torr b. 263 torr

c. 363 torr d. 463 torr

3. A sample of air occupies 73.3m L at 98.7 atm at 0 °C. What volume will the air occupy at 4.02 atm and 0 °C?

a. 150 L b. 225 L

c. 320 L d. 425 L

4. A sample of Helium occupies 535 mL at 988 mmHg and 25 °C. If the sample is transferred to a 1.05-L flask, what will be the gas pressure in the flask?

a. 1030 mL b. 1800 mL

c. 320 mL d. 500 mL

5. A cylinder of oxygen has a volume of 2.25 L. The pressure of the gas is 1470 pounds per square inch (psi) at 20 °C. What volume will the oxygen occupy at standard atmospheric pressure (14.7 psi) assuming no temperature change?

a. 503 mm Hg b. 203 mm Hg

c. 303 mm Hg d. 430 mm Hg

Charles’s Law – Volume-Temperature Relationship

1. Three liters of hydrogen at -20 °C are allowed to warm to a room of 27 °C. What is the volume at room temperature if the pressure remains constant?

a. 1.10 L b. 2.00 L

c. 3.56 L d. 4.50 L

2. If 10.5 L of nitrogen are cooled from 95 °C to 0 °C, what is the new volume?

a. 8 L b. 2 L

c. 3 L d. 5 L

3. A sample of oxygen gas occupies a volume of 2.10 L at 25 °C. What volume will this sample occupy at 150 °C?(Assume no change in pressure)

a. 2.98 L b. 4.80 L

c. 3.10 L d. 4.10 L

4. A sample of hydrogen occupies 692 L at 602 °C. If the pressure is held constant, what volume will the gas occupy after being cooled to 23 °C?

a. 400 L b. 200 L

c. 304 L d. 234 L

5. At what Celsius temperature will the initial volume of oxygen in no.2 question occupy 0.750 L?(Assume no change in pressure)

a. -167 °C b. -267 °C

c. -300 °C d. -400 °C

Ideal Gas Law

1. Use the Ideal gas law to calculate (a) the volume occupied by 1.00 mol of nitrogen gas at 244 K and 1.00 atm pressure, and (b) the pressure exerted by 0.500 mol of oxygen in a 15.0-L container at 303 K.

a. 80 L; 0.546 atm b. 20 L; 0.829 atm

c. 30 L; 0.676 atm d. 50 L; 0.898 atm

2. Determine (a) the pressure exerted by 0.0330 mol of oxygen in an 18.0-L container at 313 K, and (b) the volume occupied by 0.200 mol of nitrogen gas at 298 K and 0.980 atm.

a. 0.0471 atm; 4.99 L b. 0.0675 atm; 4.55 L

c. 0.0911 atm; 6.55 L d. 0.0673 atm; 5.55 L

3. Determine the volume of nitrogen gas produced from the decomposition of 130 g sodium azide (about the amount in a typical automobile airbag) at 25 °C and 1 atm.

a. 81.0 L b. 70.0 L

c. 73.4 L d. 52.4 L

4. Calculate the volume of 0.40 g methane, CH4, occupies at 25 °C and 1.0 atm.

a. 0.22 L b. 0.51 L

c. 0.30 L d. 0.61 L

5. What volume will 2.64 mol N2 occupy at 0.640 atm at 31 °C?

a. 102.95 L b. 223.3 L

c. 320 L d. 501.6 L

Dalton’s Law of Partial Pressures

1. Halothane is a commonly used surgical anesthetic delivered by inhalation. What is the partial pressure of each gas if 15.0 g halothane gas is mixed with 22.6 g oxygen gas and the total pressure is 862 mmHg?

a. 83.8 mm Hg; 778 mm Hg b. 85.8 mm Hg; 788 mm Hg

c. 82.8 mm Hg; 747 mm Hg d. 83.8 mm Hg; 798 mm Hg

2. A 500 mL sample of oxygen, O2, was collected over water at 23 °C and 760 torr pressure. What volume will the dry O2 occupy at 23 °C and 760 torr? The vapor pressure of water at 23 °C is 21.2 torr.

Ptotal = 760 torr = PO2 + PH2O

= 760 torr – 21.2 torr = 739 torr (pressure of dry O2)

a. 345 mL b. 205 mL

c. 486 mL d. 434 mL

3. What is the total pressure (in atm) exerted by a mixture of 12.0 g of N2 and 12.0 g of O2 in a 2.50 L container at 25.0 °C?

a. 1.62 atm b. 1.34 atm

c. 1.89 atm d. 1.77 atm

4. A 355-mL flask contains 0.146 g neon gas, Ne, and an unknown amount of argon das, Ar, at 35 °C and a total pressure of 626 mm Hg. How many grams of Ar are in the flask?

a. 7.92 atm b. 2.34 atm

c. 8.89 atm d. 1.87 atm

5. A 250 mL sample of oxygen gas is collected by water displacement. As a result, the oxygen is saturated with water vapor. The partial pressure of water vapor at the prevailing temperature is 22 torr. Calculate the partial pressure of the oxygen if the total pressure of the sample is 720 torr.



Combined Gas Law

1. Helium –filled balloons are used to carry scientific instruments high into the atmosphere. Suppose that such a balloon is launched on a summer day when the temperature at ground level is 22.5 °C and the barometer reading is 754 mmHg. If the balloon’s volume is 1.00 x 106 L at lauch, what will its volume be at a height of 37 K, where the pressure is 76.0 mmHg and the temperature is 240 K?

a. 7.05 x 106 L b. 6.05 x 106 L

c. 8.05 x 106 L d. 9.05 x 106 L

2. A small sample of a gas is prepared in the laboratory and found to occupy 21 mL at a pressure of 710 mmHg and a temperature of 22.3 °C. The next morning the temperature has changed to 26.5 °C, and the pressure is found to be 740 mmHg. No gas has escaped from the container. What volume does the sample of gas now occupy?

a. 0.02 L b. 0.01 L

c. 0.03 L d. 0.04 L

3. A gas has a volume of 800.0mL at -23.00 ºC and 300mmHg. What would the volume of the gas be if the conditions were changed to 227.0 ºC and 600mmHg?

a. 0.7 L b. 0.5 L

c. 0.8 L d. 0.1 L

4. What is the final volume of a 400.0mL gas sample that is subjected to a temperature change from 22 ºC to 30 ºC and a pressure change from 760 mmHg to 360 mmHg?

a. 0.44 L b. 0.87 L

c. 0.30 L d. 0.61 L

5. What is the final volume of a gas that is at 2 atm and 200 K but it started at 300L, .25 atm, and 400K?

a. 45 L b. 46 L

c. 47 L d. 48 L

Graham’s Law

1. The mass of a bromine molecule is 160 u, and the mass of an argon molecule is 40 u. Compare the rates at which these gases will diffuse.

a. 2 ; The Ar will diffuse twice as fast as Br2

1

b. 5 ; The Ar will diffuse twice as fast as Br2

1

c. 3; The Br2 will diffuse twice as fast as Ar 1

d. 2 ; The Ar will diffuse twice as fast as Br2

1

2. Assume a balloon that went flat first showed a sign of “flatness” 12 hours after it was filled. How long would it take for the other balloon to begin to show signs of going flat?

a. 32 hrs. b. 34 hrs.

c. 36 hrs. d. 38 hrs.

3. Hydrogen gas is lighter than oxygen gas therefore we should expect H2 to effuse at a faster rate than O2. Assuming equal temperature and pressure of the two gases, we can set up a ratio of the rates of effusion.

The rate of effusion is directly proportional to the rms speed of the molecules.

a. 4 b. 6

c. 5 d. 7

4. Calculate the ratio of the effusion rates of the hydrogen gas (H) and Uranium hexafluoride (UF).(H=2.016 g/mol; UF=352.02 g/mol)

a. 12.2 b. 14.2

c. 13.2 d. 15.2

5. An unknown gas composed of homonuclear diatomic molecules effuses at a rate that is only 0.355 times that of O2 at the same temperature. What is the identity of the unknown gas?

a. 254 g/mol; I2 b. 456 g/mol; O2

c. 355 g/mol; I2 d. 378 g/mol; O2

Gay-Lussac’s Law - Pressure-Temperature Relationship

1. A sample of O2 under 2.00 atm occupies 500 ml at 25.0˚C. What pressure will the sample have at 0.0˚C?

a. 2.11 atm b. 1.83 atm

c. 4.59 atm d. 1.87 atm

2. If a gas has a pressure of 450 mm Hg and a volume of 250 L at a temperature of 22.0˚C, what would the new temperature be at 760 mm Hg? (give answer in ˚C)

a. 225.2 °C b. 425.2 °C

c. 325.2 °C d. 525.2 °C

3. A gas at 20.0˚C is increased to 40.0˚C. What would be the new pressure be if the original pressure was 725 torr?



4. A sample of gas at 25 ˚C has a pressure of 1.2 atm. Calculate the final pressure in atmospheres if the temperature is changed to 100 ˚C at constant volume.

5. This gas law works only if temperature is recorded in ____________________ units.

a. Kelvin b. Fahrenheit

c. Celsius d. Rankine

Amagat’s Law

1. Calculate the partial volume of nitrogen if the other gases have the partial volume of 24 L, 15 L and 68 L. The total volume is 220 L.

a. 113 L b. 122 L

c. 213 L d. 123 L

2. Find the total volume given the following gases: N = 55 L, O = 36 L, H = 75 L.

a. 166 L b. 324 Lc. 56 L d. 123 L3. What is the partial volume of hydrogen if the partial volume of oxygen is 20 mL

, if the total volume of a mixture of hydrogen gas and oxygen gas is 80 mL.

a. 99.98 L a. 69.98 L

a. 79.98 L d. 59.98 L

4. What is the total volume given the partial gases: N = 35 L, O = 27 L and H = 17 L?

a. 79 L b. 67 Lc. 66 L d. 90 L

5. A 10 mol sample has a pressure of 3 atm at 450 K. The first gas has a partial volume of 4 L. The second gas have a partial volume of 20 L. What is the partial volume of the third gas?

a. 123.15 L b. 133.15 L

c. 99.15 L d. 100.15 L

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Physical Chemistry 1 Prob Set