Bell Work

1. Bell Work • Convert 15.3 atm to kPa • Convert 96.3 L of a gas at STP to moles. • What is the temperature and pressure at STP? • A scientist is trying to determine the pressure of a system that is made up of 4 gases. One gas has a pressure of 20 kPa. Another gas has a pressure of 5 kPa. The remaining two gases have a pressure of 2.5 kPa. What is the total pressure? • A system originally has a pressure of 25.2 kPa, a volume of 15.1 L and a temperature of 45.5 ˚C. What is the new volume if the pressure is decreased to 20.0 kPa and the temperature is increased to 60 ˚C? • How many moles are in a system that has a pressure of 2.5 atm, a volume of 33.3 L and a temperature of 75.2 ˚C?

2. Homework Answers • 4.69 • 1501 m/s • 17.75 g/mol • 0.485; slower • 128 g/mol; HI • 64 g/mol; SO2 • 1920 m/s

3. Reality Check • In comparing the rates of diffusion of CO2 with that of Kr, which gas will diffuse faster? • To two decimal places, what will vA/vB (treat this as x) be equal to if CO2 is considered to be A and Kr is considered to be B. • What is the molar mass of a gas if it diffuses at a rate of 647 m/s while chlorine (Cl2) gas diffuses at 840 m/s at the same temperature? After you are finished, continue working on the lab.

4. Unit 9 Review Gases

5. The Game Board

6. 1 Calculate the approximate volume of a 2.50 mol sample of gas at -8.0°C and a pressure of 3.50 atm. 15.5 L Back

7. 2 In the reaction N2 (g) + 3H2 --> 2NH3 (g), the volume ratio of H2 to N2 is___________ 3 to 1 Back

8. 3 A pressure of 165 kPa is equal to _____ atm. 1.63 Back

9. 4 What does the constant bombardment of gas molecules against the inside of a container cause? Pressure Back

10. 5 What happens to the volume of a gas during compression? The Volume Decreases Back

11. 6 A sample of a gas has a pressure of 2.25 atm, a volume of 650 mL and a temperature of 36°C. What would the volume of the gas be if the pressure is increased to 3.20 atm and the temperature is decreased to 31°C? 449.6 mL Back

12. 7 What temperature is needed to pressurize a 27.3 L container with 6.34 moles of air to 564.8 kPa? 292.5 K Back

13. 8 When pressure, volume, and temperature are known, the ideal gas law can be used to calculate ______________. Molar amount (moles) Back

14. 9 According to the diagram to the right, what PV/nRT value do ideal gases have all the time? 1.0 Back

15. 10 What is the SI unit of pressure? Pascal Back

16. 11 If a gas with an odor is released in a room, it quickly can be detected across the room because it ______________. Diffuses Back

17. 12 A pressure of 355000 Pa is equal to _____ psi. 51.5 Back

18. 13 The principle that under similar pressures and temperatures, equal volumes of gases contain the same number of molecules is attributed to ________________. Avogadro Back

19. 14 Nitrogen reacts with hydrogen to make ammonia [N2 (g) + 3H2 (g) --> 2NH3 (g)]. If one needs to produce 4 L of ammonia, how many liters of nitrogen are needed? 2 L Back

20. 15 A sample of a gas occupies a volume of 1.1 L at 33°C. What temperature is needed to increase the volume of the gas to 1.9 L, if the pressure remains constant? 528.5 K or 255°C Back

21. 16 A 10.5 L sample of a gas has a mass of 95.9 g at 7.6 atm and 35°C. What is the molar mass of the gas? (Hint: divide the given mass by n). 30.4 g/mol Back

22. 17 According to the diagram to the right, at what pressure do all the gases most resemble an ideal gas? Back 0 atm

23. 18 A pressure of 560 mmHg is equal to _____ kPa. 74.7 Back

24. 19 Who is accredited with the idea that in a reaction, two volumes of hydrogen gas will combine with one volume of oxygen gas to produce two volumes of water vapor? Gay-Lussac Back

25. 20 The pressure of each gas in a mixture is called the ____________________ pressure. Partial Back

26. 21 A sample of a gas has a pressure of 567 mmHg at 23°C. What would the gas pressure be at 41°C, if the volume remains constant? 601 mmHg Back

27. 22 To two decimal places, what will vA/vB be equal to if N2 is considered to be gas A and NO is considered to be gas B. (A diffusion problem) 1.03 Back

28. 23 Standard temperature and pressure for a gas is ____________________ 0°C and 1 atm. Back

29. 24 The total pressure of a system of four gases is 35 atm. The first gas has a pressure of 5 atm. The second gas has a pressure of 8 atm. The remaining two pressures are the same. What is the partial pressure of the other two gases? 11 Back

30. 25 Charles’s law is the direct relationship between ____________________ and volume. Temperature Back

31. 26 What is the molar mass of a gas if it diffuses at a rate of 258 m/s while Iodine gas diffuses at 125 m/s at the same temperature? 29.7 g Back

32. 27 2H2O(l) + electricity  2H2(g) + O2(g) What mass of H2O is needed to create 15.64 L of O2, if the temperature is 25°C and the pressure is 1.2 atm? 27.6 g Back

33. 28 The average kinetic energy of random motion is proportional to the temperature in what unit? Kelvin Back

34. 29 A sample of oxygen occupies 350 mL when the pressure is 5 atm. At constant temperature, what volume does the gas occupy when pressure falls to 3 atm? 583 mL Back

35. 30 Who developed the concept that the total pressure of a mixture of gases is the sum of their partial pressures? Dalton Back

36. 31 What is the theory that explains that the behavior of physical systems depends on the combined actions of the molecules constituting the system? Kinetic Molecular Theory Back

37. 32 A mixture of gases with a pressure of 800.0 mm Hg contains 60% nitrogen and 40% oxygen by volume. What is the partial pressure of oxygen in this mixture? 320 mm Hg Back

38. 33 Line D represents water. If the atmospheric pressure in a flask is lowered to 70 kPa, water would boil at what temperature? 92 C Back

39. 34 T1 = 76 C P1 = 4 atm V1 = 560 mL T2 = 92 C P2 = 2 atm V2 = ? 1171 mL Back

40. 35 The rate of diffusion of a gas depends on the ____________ of the gas. Molar Mass Back