April 4, 2012CHEM 188 – Spring, 2012Hour Exam 3 (Early)April 4, 2012Instructions:Your scantron answer sheet must show your NAME, 7-DIGIT KU ID NUMBER, and LAB SECTION. (Begin these entries at the LEFT end of the space provided.) In answering the questions, be careful to fill in the corresponding circles on the answer sheet according to the number of the question on the exam. USE A SOFT (No. 2) PENCIL. Note that a periodic table of the elements is attached at the end of the exam.Useful information: Avogadro's Number NA = 6.022 × 10 23 mol1Gas constant R = 8.314 JK1mol1 = 0.0821 LatmK1mol1Boltzmann constant k = 1.38 × 1023 JK1Conversion factor: 1 Latm = 101.3 J1. A 75 kg person drinks 250 g of milk, which has a "caloric" value of approximately 3.0 kJ/g.If only 17% of the energy in milk is converted to mechanical work, how high (in meters) can the person climb based on this energy intake? [Hint: The work done in ascending is given by mgh, where m is the mass (in kilograms), g the gravitational acceleration (9.8 m/s2), and h the height (in meters.)]A. 170 B. 260 C. 350 D. 450 E. 5602. An ideal gas is allowed to expand at constant temperature from a volume of 1.00 L to 5.00 L against a constant external pressure of 2.00 atm. What is the value of w, the work done on the gas?A. -810 J B. – 8.00 J C. 0 J D. +8.00 J E. +810 J3. Calculate w, the work done on the system, when 80.0 g of potassium reacts with water to form hydrogen gas at 2.00 atm and 40oC. (Assume ideal gas behavior.) 2K(s) + H2O(l)  2KOH(aq) + H2(g)A. –0.333 kJ B. –0.666 kJ C. –1.33 kJ D. –2.66 kJ E. none of these14. A gas expands and does P-V work on the surroundings equal to 400 J. At the same time, itreleases 150 J of heat to the surroundings. What is the change, U, in the internal energy of the gas?A. 550 J B. 250 J C. 0 J D. –150 J E. –550 J5. Given the thermochemical equationH2(g) + Cl2(g)  2HCl(g) H = 184.2 kJcalculate the enthalpy change, H, for the reaction HCl(g)  ½ H2(g) + ½ Cl2(g)A. –184.6 kJ B. –92.3 kJ C. 0 kJ D. 92.3 kJ E. 184.6 kJ6. The combustion of methane produces heat according to the equationCH4(g) + 2O2(g)  CO2(g) + 2H2O(l) Horxn = 890 kJHow much heat is generated by the combustion of 20 g of methane?A. 890 kJ B. 1,100 kJ C. 2,800 kJ D. 4,200 kJ E. 5,600 kJ7. Given the following thermochemical equation, calculate the value of U for the formation of 3 moles of NH3 at 1.00 atm and 25oC? N2(g) + 3H2(g)  2NH3(g) + 92.6 kJA. –131.4 kJ B. –135.2 kJ C. –138.9 kJ D. –142.5 kJ E. –146.4 kJ8. If 325 g of water at 4.2°C absorbs 12.3 kJ of heat, what is the final temperature of the water? The specific heat of water is 4.184 J/g·°C.A. 10.0°C B. 12.2°C C. 13.2°C D. 15.6°C E. 18.0°C 9. A 1.75 g sample of octane (C8H18) was burned in an oxygen bomb calorimeter. The total heat capacity of the calorimeter plus water was 11.5 kJ/°C. If the temperature rise of the calorimeter with water was 7.30°C, calculate the molar value of U for the combustion of octane.A. 5,650 kJ/mol B. 5,470 kJ/mol C. –3,230 kJ/mol D. –2,810 kJ/mol E. 1,370 kJ/mol 210. To which one of the following reactions occurring at 25°C and 1.00 atm pressure does the symbol H°f[CO2(g)] refer?A. C(g) + O2(g)  CO2(s)B. C(s) + O2(g)  CO2(g)C. CO(g) + ½ O2(g)  CO2(g)D. C(s) + 2O(g)  CO2(g)E. CO2(g)  C(s) + O2(g) 11. All of the following have a standard enthalpy of formation value of zero at 25oC and 1.00 atm, except …1. He(g) 2. Fe(s)3. O3(g)4. NO(g)A. 2 only B. 3 only C. 4 only D. 2 & 4 E. 3 & 412. Determine the standard enthalpy of formation, ΔHof, for HBr(g), given the following thermochemical equation: H2(g) + Br2(l)  2HBr(g) + 72.4 kJA. –72.4 kJ B. –36.2 kJ C. 0 kJ D. 36.2 kJ E. 72.4 kJ13. Octane (C8H18) undergoes combustion according to the following thermochemical equation: 2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(l) H°rxn = 11,020 kJ/mol.Given that H°f[CO2(g)] = 393.5 kJ/mol and H°f[H2O(l)] = 285.8 kJ/mol, calculate the standard enthalpy of formation of octane.A. 210 kJ/mol B. 11,230 kJ/mol C. 22,040 kJ/mol D. 420 kJ/mol E. 420 kJ/mol14. Consider the following two reactions:(1) A  2B H1 = 200 kJ3(2) B  C H2 = 100 kJDetermine the enthalpy change, H3, for the process(3) A  2CA. –300 kJ B. –100 kJ C. 0 kJ D. +100 kJ E. +300 kJ15. Given that the molar enthalpy of formation, ΔHof, of H2O(l) is –285.8 kJ/mol, how many grams of H2 would be required to produce 200. kJ of heat from the complete combustion of H2(g) with an excess of O2(g)? 2H2(g) + O2(g)  2H2O(l)A. 0.705 g B. 1.41 g C. 2.82 g D. 5.64 g E. 11.3 g16. Which of the following is a spontaneous change? 1. ice melting at 5oC 2. heat flowing from a hot to a cold object 3. two gases mixingA. 1 only 2. 2 only C. 3 only D. 2 & 3 only E. 1, 2, & 317. Consider a sample of solid mono-deuterated methane, CH3D, consisting of six molecules of CH3D, each of which can be oriented in any of four directions. If these four directions are equally probable, how many ways, W, can these six molecules be arranged?A. 6 B. 48 C. 1,024 D. 4,096 E. 16,38418. In solid carbon monoxide, a given CO molecule may be oriented in either of two directions. If these two directions are equally probable (i.e., the arrangement is totally random), what would be the entropy of 0.500 mole of CO(s)?A. 0 J/K B. 0.58 J/K C. 1.44 J/K D. 2.88 J/K E. 5.76 J/K19. For which of the following processes will the entropy of the system increase? 1. a solid melts 2. a liquid freezes 3. a liquid boils 4. a vapor condenses 5. a gas is compressed isothermallyA. 1 & 3 only B. 2 & 4 only C. 3 & 5 only D. 1 & 5 only E. 1, 3 & 5 only420. Arrange the following compounds in order of increasing standard molar entropy at 25C: C3H8(g), C2H4(g), ZnS(s), and H2O(l).A. ZnS(s) < H2O(l) < C3H8(g) < C2H4(g)B. C2H4(g) < H2O(l) < C3H8(g) < NaCl(s) C. ZnS(s) < C3H8(g) < C2H4(g) < H2O(l) D. C3H8(g) < C2H4(g) < H2O(l) < ZnS(s)E. ZnS(s) < H2O(l) < C2H4(g) < C3H8(g)21. Which response includes all the following processes that are accompanied by an increase in entropy?1. 2I(g)  I2(g)2. I2(s) 