1. General Chemistry Principles & Modern Applications 9 th Edition Petrucci/Harwood/Herring/Madura Chapter 6 Gases Dr. Travis D. Fridgen Memorial University of Newfoundland © 2007 Pearson Education

2. In which of the figures below is the pressure in the gas bulb greater than atmospheric pressure? 1.2.3.

3. In which of the figures below is the pressure in the gas bulb greater than atmospheric pressure? 1.2.3.

4. Edgar Degas, Danseuses bleues, 1890 Musee d’Orsay, Paris What is the pressure exerted by a 50 kg ballet dancer standing on her toe (~2 cm 2 ). Assume g is ~10 m s -2. (Note: atmospheric pressure is ~1x10 5 Pa 4. 2.5x10 6 Pa 1. 0.025 Pa 2. 250 Pa 3. 2.5x10 4 Pa 5. 2.5x10 8 Pa

5. Edgar Degas, Danseuses bleues, 1890 Musee d’Orsay, Paris What is the pressure exerted by a 50 kg ballet dancer standing on her toe (~2 cm 2 ). Assume g is ~10 m s -2. (Note: atmospheric pressure is ~1x10 5 Pa 4. 2.5x10 6 Pa 1. 0.025 Pa 2. 250 Pa 3. 2.5x10 4 Pa 5. 2.5x10 8 Pa

6. Boyle’s law as an equation is An expression for the final volume, V 2, occupied by a gas from the initial volume, V 1, when the pressure is changed from P 1 to P 2 at constant temperature is,

7. Boyle’s law as an equation is An expression for the final volume, V 2, occupied by a gas from the initial volume, V 1, when the pressure is changed from P 1 to P 2 at constant temperature is,

8. 100 L P 1 =30 atmP 1 =10 atm V=? A 100 L vessel at 30 atm is attached to another vessel and gas is allowed to equilibrate between the two. The pressure was then found to be 10 atm. Use Boyle’s Law to determine the Volume of the second, oddly shaped, container. 2. 100 L 3. 200 L 4. 300 L 1. 50 L 5. 400 L

9. 100 L P 1 =30 atmP 1 =10 atm V=? A 100 L vessel at 30 atm is attached to another vessel and gas is allowed to equilibrate between the two. The pressure was then found to be 10 atm. Use Boyle’s Law to determine the Volume of the second, oddly shaped, container. 2. 100 L 3. 200 L 4. 300 L 1. 50 L 5. 400 L

10. Charles’ law as an equation is An expression for the final volume, V 2, occupied by a gas from the initial volume, V 1, when the temperature is increased from T 1 to T 2 at constant pressure is,

11. Charles’ law as an equation is An expression for the final volume, V 2, occupied by a gas from the initial volume, V 1, when the temperature is increased from T 1 to T 2 at constant pressure is,

12. Without doing detailed calculations, which of the following gases has the greatest density at STP? 1. O 2 2. N 2 3. Kr 4. CH 4 5. C 3 H 6

13. Without doing detailed calculations, which of the following gases has the greatest density at STP? 1. O 2 2. N 2 3. Kr 4. CH 4 5. C 3 H 6

14. You take a 2.0 L volume of gas at 25 o C. You double both the volume and the temperature to 4.0 L and 50 o C, respectively. The pressure of the gas… 2 L 4 L 25 o C 50 o C Caricature of Bunsen by William B. Jensen 1. Doubles 2. Quadruples 3. Halves 4. Remains the same 5. None of these answers

15. You take a 2.0 L volume of gas at 25 o C. You double both the volume and the temperature to 4.0 L and 50 o C, respectively. The pressure of the gas… 2 L 4 L 25 o C 50 o C Caricature of Bunsen by William B. Jensen 1. Doubles 2. Quadruples 3. Halves 4. Remains the same 5. None of these answers

16. You take a 4.0 L volume of gas at 300 K. You compress the gas to a 2.0 L volume and simultaneously heat the vessel to 600 K. The pressure of the gas… 2 L 4 L 600 K 300 K Caricature of Bunsen by William B. Jensen 1. Doubles 2. Quadruples 3. Halves 4. Remains the same 5. None of these answers

17. You take a 4.0 L volume of gas at 300 K. You compress the gas to a 2.0 L volume and simultaneously heat the vessel to 600 K. The pressure of the gas… 2 L 4 L 600 K 300 K Caricature of Bunsen by William B. Jensen 1. Doubles 2. Quadruples 3. Halves 4. Remains the same 5. None of these answers

18. The contents of two 5 L containers, one containing H 2 and the other containing He are combined as depicted to the right. What is the final Pressure of the 5.0 L vessel? 5.0 L @ 20 o C ? ? ? ? ? 0.50 mol H 2 P=2.4 atm 1.25 mol He P=6.0 atm 0.50 mol H 2 1.25 mol He P=? 1. 1.75 atm 2. 2.4 atm 3. 6.0 atm 4. 8.4 atm 5. 10.8 atm

19. The contents of two 5 L containers, one containing H 2 and the other containing He are combined as depicted to the right. What is the final Pressure of the 5.0 L vessel? 5.0 L @ 20 o C ? ? ? ? ? 0.50 mol H 2 P=2.4 atm 1.25 mol He P=6.0 atm 0.50 mol H 2 1.25 mol He P=? 1. 1.75 atm 2. 2.4 atm 3. 6.0 atm 4. 8.4 atm 5. 10.8 atm

20. In the electrolysis of a sample of water 100 mL of O 2 was collected. What volume of H 2 was collected? 1. 20 mL 2. 50 mL 3. 100 mL 4. 150 mL 5. 200 mL

21. In the electrolysis of a sample of water 100 mL of O 2 was collected. What volume of H 2 was collected? 1. 20 mL 2. 50 mL 3. 100 mL 4. 150 mL 5. 200 mL

22. 0.5 mol of water was decomposed in an electrolysis experiment. What volume each of H 2 and O 2 were collected at STP? 1. 22.4 L of each. 2. 11.2 L of each. 3. 11.2 L H 2, 22.4 L of O 2. 4. 22.4 L H 2, 11.2 L of O 2. 5. 22.4 L H 2, 44.8 L of O 2.

23. 0.5 mol of water was decomposed in an electrolysis experiment. What volume each of H 2 and O 2 were collected at STP? 1. 22.4 L of each. 2. 11.2 L of each. 3. 11.2 L H 2, 22.4 L of O 2. 4. 22.4 L H 2, 11.2 L of O 2. 5. 22.4 L H 2, 44.8 L of O 2.

24. What volume of hydrogen at STP is required to hydrogenate one mole of oleic acid (C 17 H 33 COOH) to one mole of stearic acid (C 17 H 35 COOH)? 1. 11.2 L 2. 22.4 L 3. 44.8 L 4. 56.0 L 5. 67.2 L

25. What volume of hydrogen at STP is required to hydrogenate one mole of oleic acid (C 17 H 33 COOH) to one mole of stearic acid (C 17 H 35 COOH)? 1. 11.2 L 2. 22.4 L 3. 44.8 L 4. 56.0 L 5. 67.2 L

26. NaH and CaH 2 react with water to produce hydrogen gas according to the following equation. The molar masses of Na and Ca are, 22.99 and 40.08 g mol -1, respectively. Which produces the most H 2 per gram? 1. NaH 2. CaH 2 3. Per gram, both produce the same.

27. NaH and CaH 2 react with water to produce hydrogen gas according to the following equation. The molar masses of Na and Ca are, 22.99 and 40.08 g mol -1, respectively. Which produces the most H 2 per gram? 1. NaH 2. CaH 2 3. Per gram, both produce the same.

28. According to the kinetic molecular theory the root mean square speed of ammonia, NH 3, is 660 m s -1 at 298 K. That means that 30 ms after taking the top off a bottle of ammonium hydroxide a person at the back of a room, 20 m away, will experience the debilitating odor of ammonia (choose the best response). 1. True 2. False 3.This is a flaw with the kinetic molecular theory.

29. According to the kinetic molecular theory the root mean square speed of ammonia, NH 3, is 660 m s -1 at 298 K. That means that 30 ms after taking the top off a bottle of ammonium hydroxide a person at the back of a room, 20 m away, will experience the debilitating odor of ammonia (choose the best response). 1. True 2. False 3.This is a flaw with the kinetic molecular theory.

30. The normal economical cruising speed of a Boeing 767 is 854 km h -1 (237 m s -1 ). Xe (131.29 g mol -1 ) has about the same root mean square speed at 298 K. Which of the following gases would beat the Boeing 767 in a race? 1. Cl 2 2. Kr 3. Br 2 4. Both 1 and 2. 5. All of these. 17 Cl 35.4527 35 Br 79.904 36 Kr 83.80

31. The normal economical cruising speed of a Boeing 767 is 854 km h -1 (237 m s -1 ). Xe (131.29 g mol -1 ) has about the same root mean square speed at 298 K. Which of the following gases would beat the Boeing 767 in a race? 1. Cl 2 2. Kr 3. Br 2 4. Both 1 and 2. 5. All of these. 17 Cl 35.4527 35 Br 79.904 36 Kr 83.80

32. 5. None of the above answers explains this strange observation. At 320 K and 16 atm, the molar volume of ammonia, NH 3, is about 10% less than that of an ideal gas. The best explanation for this observation is 1. The volume of an NH 3 molecule is significant at this concentration. 2.The volume of an NH 3 molecule is smaller than that of an ideal gas. 3.At this temperature, a significant amount of NH 3 decomposes to N 2 and H 2. 4.Intermolecular forces of attraction for NH 3 become significant at this temperature and pressure.

33. 5. None of the above answers explains this strange observation. At 320 K and 16 atm, the molar volume of ammonia, NH 3, is about 10% less than that of an ideal gas. The best explanation for this observation is 1. The volume of an NH 3 molecule is significant at this concentration. 2.The volume of an NH 3 molecule is smaller than that of an ideal gas. 3.At this temperature, a significant amount of NH 3 decomposes to N 2 and H 2. 4.Intermolecular forces of attraction for NH 3 become significant at this temperature and pressure.

34. There are always attractive forces between a collection of atoms or molecules which may not be negligible as suggested by the kinetic molecular theory. The strength of these forces depend upon the nature of the atom or molecule. If a mole of gas is at STP and there are very strong attractive intermolecular forces between the gas particles the volume will be atm P 1. 22.4 L 2. greater than 22.4 L 3. less than 22.4 L 3. none of these

35. There are always attractive forces between a collection of atoms or molecules which may not be negligible as suggested by the kinetic molecular theory. The strength of these forces depend upon the nature of the atom or molecule. If a mole of gas is at STP and there are very strong attractive intermolecular forces between the gas particles the volume will be atm P 1. 22.4 L 2. greater than 22.4 L 3. less than 22.4 L 3. none of these

36. If you have a mole of a real gas in which there are substantial intermolecular forces between the gas molecules in a 22.4 L container at 273 K (standard temperature) will the pressure be 1. 1 atmosphere 3. less than 1 atm 2. greater than 1 atm

37. If you have a mole of a real gas in which there are substantial intermolecular forces between the gas molecules in a 22.4 L container at 273 K (standard temperature) will the pressure be 1. 1 atmosphere 3. less than 1 atm 2. greater than 1 atm