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Unformatted text preview: Sample Test 2
Test no. 2 will consist of 14 multiple-choice questions of the type below and three problems to be worked fully. The problems will be of the type assigned for homework. One or more will be directly from the homework sets. Note: any material covered in class may be subject to testing. RH = 2.180 x 10-18 J; h = 6.63x10-34 J s; You are expected to know speed of light c, conversion from J to cal. and mass of element up to and including Neon. 1. The oxidation numbers of nitrogen in N2O and N2F4 are, respectively, a. 2 and 3. b. 2 and +2. c. +1 and 1. d. +1 and +2. e. +1 and 3. 2 Which of the following chemical reactions is an oxidationreduction reaction? a. Zn(s) + S(s) ZnS(s) b. H2SO4 + 2NaOH Na2SO4 + 2H2O c. CO2+ H2O H2CO3 d. AgNO3 + NaCl AgCl + NaNO3 e. NaOH + HCl NaCl + H2O 3. All the following half-reactions are balanced EXCEPT a. 2H2O + 2e- H2 + 2OH-. b. NO3- + 4H+ + 3e- NO + 2H2O. c. 2Ta + 5H2O Ta2O5 + 10H+ + 10e-. d. H3PO3 + H2O H3PO4 + 2H+ + 2e-. e. H2O2 2OH- + 2e-. 4. When the equation HBrO3 + SO2 + H2O Br2 + H2SO4 is balanced, the coefficient for SO2 is a. 5. b. 4. c. 8. d. 10. e. 7. 5 Absolute zero is the temperature at which a. gaseous helium liquefies. b. a straight-line graph of P versus 1/V intersects the 1/V axis. c. a straight-line graph of V versus 1/P intersects the 1/P axis. d. a graph of P versus V at constant T intersects the V axis. e. a straight-line graph of V versus T intersects the T axis. 1 6. When ammonium nitrite undergoes decomposition, only gases are produced, according to the equation NH4NO2(s) N2(g) + 2H2O(g)
What is the total volume of gases produced at 1092 K and 1.00 atm pressure when 192 g of ammonium nitrite undergoes the foregoing decomposition reaction? a. b. c. d. e. 6 x 22.4 L 9 x 22.4 L 12 x 22.4 L 18 x 22.4 L 36 x 22.4 L 7. At 23C and 325 mmHg, an unknown pure gas has a density of 0.493 g/L. Which of the following gases could be the unknown gas? a. N2O b. He c. C2H6 d. CO e. F2 8. The properties of a real gas are MOST likely to deviate from those properties predicted for an ideal gas when a. the pressure is low. b. the temperature is high. c. the pressure is high and the temperature is low. d. the pressure is low and the temperature is high. e. All the above are true. 9. It takes 16.6 min for a 10.0-mL sample of an unknown gas to effuse through a pinhole. A 10.0-mL sample of helium, He, required 5.00 min. What is the molecular weight of the unknown gas? a. 13.3 g/mol b. 44.1 g/mol c. 177 g/mol d. 7.3 g/mol e. 53.1 g/mol 10. From a consideration of the van der Waals constants for water and sulfur dioxide, a(atm L2/mol 2 )
H2O SO2 5.54 6.87 b(L/mol)
0.0305 0.0568 we can conclude that a. H2O molecules are smaller and less attracted to each other than SO2 molecules. b. H2O molecules are smaller and more attracted to each other than SO2 molecules. c. H2O molecules are larger and more attracted to each other than SO2 molecules. d. H2O molecules are larger and less attracted to each other than SO2 molecules. e. None of these conclusions is correct. 2 11. A 150.0-g sample of metal at 80.0C is added to 150.0 g of H2O at 20.0C. The temperature rises to 23.3C. Assuming that the calorimeter is a perfect insulator, what is the specific heat of the metal? a. 0.48 J/(g C) b. 0.24 J/(g C) c. 0.48 J/(g C) d. 0.72 J/(g C) e. 0.96 J/(g C) 12. H2 and F2 react according to the following equation, forming HF. H2 + F2 2HF H = 271 kJ/mol If H2(g) and F2(g) were mixed in a thermally insulated vessel, the reaction that occurred would be a. exothermic, and the temperature of the reaction system would rise. b. endothermic, and the temperature of the reaction system would rise. c. endothermic, and the temperature of the reaction system would fall. d. exothermic, and the temperature of the reaction system would fall. e. We could not tell unless the original and final temperatures were given. 13. Given that O(g) + e O(g) + 2e O-(g) + e is a. b. c. d. e. 14. 844 kJ. 560 kJ. 0 kJ. 560 kJ. 844 kJ. O-(g) O2-(g) O2-(g) H = 142 kJ mol-1 H = 702 kJ mol-1 the enthalpy change for the reaction represented by the equation Rank the following regions of the electromagnetic spectrum in order of increasing energy. x rays, microwaves, infrared, ultraviolet a. b. c. d. e. x rays, microwaves, infrared, ultraviolet microwaves, ultraviolet, infrared, x rays microwaves, infrared, ultraviolet, x rays infrared, microwaves, ultraviolet, x rays infrared, ultraviolet, x rays, microwaves 3 15. Which of the following statements is (are) TRUE? 1. The product of wavelength and frequency of light is a constant. 2. As the energy increases, the frequency of the radiation decreases. 3. As the wavelength of light increases, the frequency increases. a. b. c. d. e. 1 only 2 only 3 only 1 and 3 only 2 and 3 only 16. What is the wavelength of light emitted when the hydrogen atom undergoes a transition from level n = 4 to level n = 2? a. b. c. d. e. 17. 663 nm 833 nm 546 nm 521 nm 486 nm All the following statements concerning the development of modern atomic theory are correct EXCEPT a. Rutherford's alpha particle scattering experiment demonstrated that most of the mass of an atom is in a small dense nucleus. b. the Heisenberg uncertainty principle; we know that it is impossible to determine accurately both the position and velocity of an atomic particle. c. Millikan's oil droplet experiment provided information for the calculation of the charge of an electron. d. de Broiglie reasoned that matter could have both wave and particle properties. e. Davisson and Germer obtained evidence for the particle character of electrons by diffracting a beam of electrons through a crystal. Answers:
1d 2a 3e 4a 5e 6e 7d 8c 9b 10 a 11 b 12 a 13 e 14 c 15 a 16 e 17 e Solutions to the numerical multiple-choice problems are also provided. 4 ...
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This note was uploaded on 06/03/2008 for the course CH 109 taught by Professor Davidovits during the Fall '07 term at BC.
- Fall '07