Quiz 20:

1. Charles' law states that...

• A. the volume of an ideal gas is proportional to its temperature if its pressure is kept constant
• B. the volume of a gas is inversely proportional to its pressure if its temperature is kept constant
• C. the volume of a gas is directly proportional to its temperature and inversely proportional to its pressure.
• D. the volume of a gas is proportional to its pressure if its temperature is kept constant.
• E. the volume of a gas is inversely proportional to its temperature if its pressure is kept constant.

2. Which of the following is a correct statement?

• A. Molecular mass of a compound is the mass of one molecule of the compound expressed in grams.
• B. Molecular mass of a compound is equal to the mass of one mole of the substance.
• C. Molecular mass of a compound is the mass of Avogadro number of molecules of the compound expressed in atomic mass unit.
• D. Molecular mass of a compound is the mass of Avogadro number of molecules of the compound expressed in grams.
• E. Molecular mass of a compound is the mass of one molecule of the compound expressed in atomic mass unit

3. A gas has a volume of 30 L at a pressure of 50 kPa and a temperature of 30 °C. Calculate its volume at a pressure of 95 kPa and a temperature of 65 °C.

• A. 31.643 L
• B. 7.841 L
• C. 17.613 L
• D. 3.624 L
• E. 15.722 L

4. A gas in a balloon has a volume of 110 L at a temperature of 60 °C. Calculate its temperature when its volume is changed to 65 L at constant pressure.

• A. -48.834 °C
• B. -99.145 °C
• C. -35.112 °C
• D. -22.19 °C
• E. -76.227 °C

5. Calculate the volume of 0.4 moles of a gas at STP.

• A. 13.41 L
• B. 16.156 L
• C. 6.639 L
• D. 8.947 L
• E. 1.845 L

6. Calculate the pressure of 100 g of carbon mono-oxide ( CO ) gas that has a volume of 4 L at a temperature of 70 °C. (atomic masses of carbon and oxygen are 12 and 16 u respectively.)

• A. 3234.513 kPa
• B. 1194.653 kPa
• C. 2541.875 kPa
• D. 4166.087 kPa
• E. 3731.008 kPa

7. Calculate the pressure of a sample of a gas that contains 3e23 molecules and occupies a volume of 140 L at a temperature of 80 °C.

• A. 13.311 kPa
• B. 10.439 kPa
• C. 4.283 kPa
• D. 8.995 kPa
• E. 15.188 kPa

8. A 90 g sample of di-atomic hydrogen ( H2 ) gas is at a temperature of 30 °C. Calculate the average energy (translational kinetic energy) of one hydrogen molecule of the sample.

• A. 6.272e-21 J
• B. 0.681e-21 J
• C. 9.316e-21 J
• D. 7.418e-21 J
• E. 3.062e-21 J

9. A 50 g sample of di-atomic Nitrogen ( N2 ) gas is at a temperature of 40 °C. Calculate the total energy (translational kinetic energy) of the sample. (atomic mass of nitrogen is 14 u. )

• A. 8962.634 J
• B. 6958.661 J
• C. 5865.368 J
• D. 4892.043 J
• E. 12246.782 J

10. A 70 g sample of di-atomic Oxygen ( O2 ) gas is at a temperature of 50 °C. Calculate the RMS (root mean square) speed of the molecules of the sample. (atomic mass of Oxygen is 16 u. )

• A. 440.824 m ⁄ s
• B. 501.333 m ⁄ s
• C. 50.906 m ⁄ s
• D. 303.677 m ⁄ s
• E. 365.417 m ⁄ s