Experiment Initial [A] Initial [B] Initial Rate

Chem 120 Practice Final Winter 2014 1 of 14 1. The following are initial rate data for: A + 2 B C + 2 D Experiment Initial [A] Initial [B] Initial Rate 1 0.10 0.10 0.300 2 0.20 0.10 0.600 3 0.10 0.20 1.200 A. The rate law is Rate = k[a] 1 [B] 2. B. The rate law is Rate = k[a] 0 [B] 2. C. The rate law is Rate = k[a] 2 [B] 0. D. The rate law is Rate = k[a] 2 [B] 1. E. The rate law is Rate = k[a] 1 [B] 1. 2. A particular first-order reaction has a rate constant of 1.35 x 10 2 s -1 at 25.0 C. What is the magnitude of k at 75.0 C if E A = 85.6 kj/mol? A. 3.47 x 10 4 B. 1.92 x 10 4 C. 670 D. 3.85 x 10 6 E. 1.36 x 10 2 3. For the overall chemical reaction shown below, which one of the following statements can be rightly assumed? 2H 2S(g) + O 2(g) 2S(s) + 2H 2O(l) A. The reaction is third-order overall. B. The reaction is second-order overall. C. The rate law is, rate = k[h 2S] 2 [O 2]. D. The rate law is, rate = k[h 2S] [O 2]. E. The rate law cannot be determined from the information given. 4. The reaction A(g) + 2B(g) C(g) was allowed to come to equilibrium. The initial amounts of reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 mol B. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate K c for this reaction. A. 0.060 B. 5.1 C. 17 D. 19 E. 25

Chem 120 Practice Final Winter 2014 2 of 14 5. If the reaction 2H 2S(g) 2H 2(g) + S 2(g) is carried out at 1065 C, K p = 0.0120. Starting from pure H 2S introduced into an evacuated vessel at 1065 C, what will the total pressure in the vessel be at equilibrium if the equilibrated mixture contains 0.300 atm of H 2(g)? A. 1.06 atm B. 1.36 atm C. 2.39 atm D. 4.20 atm E. 1.51 atm 6. When the substances in the equation below are at equilibrium, at pressure P and temperature T, the equilibrium can be shifted to favor the products by CuO(s) + H 2(g) H 2O(g) + Cu(s) Hº rxn = -2.0 kj/mol A. increasing the pressure by means of a moving piston at constant T. B. increasing the pressure by adding an inert gas such as nitrogen. C. decreasing the temperature. D. allowing some gases to escape at constant P and T. E. adding a catalyst. 7. Hydrogen iodide decomposes according to the equation 2HI(g) H 2(g) + I 2(g), for which K c = 0.0156 at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC. Calculate the concentration of H 2 at equilibrium. A. 0.275 M B. 0.138 M C. 0.0275 M D. 0.0550 M E. 0.220 M 8. The following reactions occur at 500 K. Arrange them in order of increasing tendency to proceed to completion (least completion greatest completion). A. 2 < 1 < 3 < 4 B. 3 < 1 < 4 < 2 C. 3 < 4 < 1 < 2 D. 4 < 3 < 2 < 1 E. 4 < 3 < 1 < 2

Chem 120 Practice Final Winter 2014 3 of 14 9. Ozone (O 3) in the atmosphere can be converted to oxygen gas by reaction with nitric oxide (NO). (Nitrogen dioxide is also produced in the reaction.) What is the enthalpy change when 8.50L of ozone at a pressure of 1.00 atm and 25 C reacts with 12.00 L of nitric oxide at the same initial pressure and temperature? [ H f (NO) = 90.4 kj/mol; H f (NO 2) = 33.85 kj/mol; H f (O 3) = 142.2 kj/mol] A. -69.2 kj B. -19.7 kj C. -1690 kj D. -97.6 kj E. -167 kj 10. Given the thermochemical equation 2SO 2 + O 2 2SO 3, H rxn = -198 kj/mol, what is the standard enthalpy change for the decomposition of one mole of SO 3? A. 198 kj/mol B. -99 kj/mol C. 99 kj/mol D. 396 kj/mol E. -198 kj/mol 11. At 1500 C the equilibrium constant for the reaction CO(g) + 2H 2(g) CH 3OH(g) has the value K p = 1.4 10-7. Calculate G for this reaction at 1500 C. A. 105 kj/mol B. 1.07 kj/mol C. -233 kj/mol D. -105 kj/mol E. 233 kj/mol 12. Find the temperature at which K p = 4.00 for the reaction N 2O 4(g) 2NO 2(g). [Given: at 25 C, for NO 2(g), H f = 33.85 kj/mol, S = 240.46 J/mol K; for N 2O 4(g), H f = 9.66 kj/mol, S = 304.3 J/mol K; assume that H and S are independent of temperature.] A. 197 C B. 56 C C. 36 C D. 79 C E. 476 C 13. The process below has H = -112 kj/mol and S = -8.07 J/mol K. What is G for this process at 25 C? Si(s) + C(graphite) SiC(s) A. -110 kj/mol B. 2.29 x 103 kj/mol C. -13.9 kj/mol D. -114 kj/mol

Chem 120 Practice Final Winter 2014 4 of 14 14. Use the reactions and G values below to determine G for: 3 CH4(g) + 4 O2(g) C3O2(g) + 6 H2O(g) For CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g), G = -800.8 kj/mol For 3 CO2(g) C3O2(g) + 2 O2(g), G = +1073.4 kj/mol A. 272.6 kj/mol B. -345.8 kj/mol C. -1329.0 kj/mol D. 817.8 kj/mol 15. The normal freezing point of ammonia is -78 C. Predict the signs of H, S, and G for ammonia when it freezes at -80 C and 1 atm: NH 3(l) NH 3(s) A. A B. B C. C D. D E. E 16. Consider the reaction: 3 N2(g) + 2 O3(g) 6 NO(g) H f in kj/mol = 0.00, 142.26, and 90.37 S in J/mol.K = 191.5, 237.7, and 210.6 (a) What is the H rxn for this reaction in kj/mol? (b) What is S rxn for this reaction in J/mol.K? (c) What is G rxn for this reaction in kj/mol at 500 K? A. 257.70, (b) -213.70, (c) -150.85 B. -257.7, (b) 213.7, (c) -150.85 C. 257.70, (b) 213.70, (c) 150.85 D. -257.70, (b) -213.70, (c) 150.85 E. -257.70, (b) 213.7 (c) 150.85

Chem 120 Practice Final Winter 2014 5 of 14 17. The vapor pressure of cyclohexane, C 6H 12, is 97.6 mmhg at 25 C, and H vapn = 23.1 kj/mol. At what temperature will the vapor pressure of cyclohexane be 175 mmhg? A. 4.84 K B. 298 K C. 280 K D. 0.00314 K E. 318 K 18. What is the ph of a 0.030 M solution of C 18H 21O 3N (codeine)? K b = 8.9 x 10-7. A. 6.43 B. 10.21 C. 12.48 D. 3.79 E. 10.98 19. Which of the following is true concerning this acid-base reaction? HS - + CH 3Cl CH 3SH + Cl - A. CH 3Cl is a Brønsted-Lowry acid. B. HS - is a Brønsted-Lowry acid. C. CH 3Cl is a Lewis base. D. HS - is a Lewis base. E. HS - is a Lewis acid. 20. Which of the following 0.100 M aqueous solutions has the highest ph? A. NaNO 3 B. Na 3PO 4 C. HOBr D. CH 3COOK E. NH 4I 21. Calculate the ph of a solution that is 0.132 M in diethylamine, (CH 3CH 2) 2NH, and 0.145 M in diethylammonium chloride, (CH 3CH 2) 2NH 2Cl. (CH 3CH 2) 2NH + H 2O (CH 3CH 2) 2NH 2 + + OH - K b = 6.9 x 10-4 A. ph = 11.98 B. ph = 6.3 x 10-4 C. ph = 3.20 D. ph = 12.14 E. ph = 10.80

Chem 120 Practice Final Winter 2014 6 of 14 22. A 100.0-mL solution is 0.74 M HC 2H 3O 2 and 0.62 M NaC 2H 3O 2. What is the ph of the solution that results from adding 1.00 g NaOH to this solution? The K a of HC 2H 3O 2 is 1.8 x 10-5. A. 4.50 B. 4.99 C. 4.67 D. 4.85 E. 5.12 23. When making 500.0 ml of a buffer solution at ph 4.00 from 0.100 M NaCHO 2 and 0.200 M HCHO 2, what volume of each solution should be used to obtain a solution with the maximum buffering capacity at this ph? The K a of HCHO 2 is 1.8 x 10-4. A. 0.39 L NaCHO 2 and 0.11 L HCHO 2 B. 0.33 L NaCHO 2 and 0.17 L HCHO 2 C. 0.39 L NaCHO 2 and 0.11 L HCHO 2 D. 0.44 L NaCHO 2 and 0.060 L HCHO 2 24. What is the ph of a solution prepared by adding 5.00 g NH 4Cl to 100.0 ml of 0.40 M NH 3? The K b of NH 3 is 1.8 x 10-5. A. 5.11 B. 8.41 C. 9.62 D. 8.89 25. A solution is prepared by diluting 0.200 mole of a base to 1.00 liter. The solution has a ph = 12.68. What is K b of the base? A. 2.2 x 10-25 B. 0.0023 C. 0.011 D. 0.24 E. 0.015 26. What is the OH - ion concentration in a 5.2 10-4 M HNO 3 solution? A. 1.9 10-11 M B. 1.0 10-7 M C. 5.2 10-4 M D. Zero E. 1.0 10-4 M 27.The ph of a solution of NH 4C 2H 3O 2 is approximately 7. The best explanation is that: A. all salts of weak acids and weak bases are neutral. B. This salt does not react with water. C. ammonium acetate is a weak electrolyte. D. aqueous ammonia and acetic acid have approximately equal ionization constants.

Chem 120 Practice Final Winter 2014 7 of 14 28. A solution is 40.0% by volume benzene (C 6H 6) in carbon tetrachloride at 20 C. The vapor pressure of pure benzene at this temperature is 74.61 mmhg and its density is 0.87865 g/cm 3 ; the vapor pressure of pure carbon tetrachloride is 91.32 mmhg and its density is 1.5940 g/cm 3. If this solution is ideal, its total vapor pressure at 20 C is A. 84.64 mmhg. B. 84.30 mmhg. C. 82.96 mmhg. D. 81.63 mmhg. E. 165.93 mmhg. 29. A solution is prepared at 27 C from 100.0 g C 6H 14 and 100.0 g C 7H 16. At this temperature, P of C 6H 14 is 165 mmhg and P of C 7H 16 is 52.8 mmhg. What is the vapor pressure of the solution at 27 C? A. 218 mmhg B. 113.2 mmhg C. 117.2 mmhg D. 108.9 mmhg 30. A 810-mL solution contains 750 grams of C 2H 5OH (ethanol) and 85.0 grams of C 6H 12O 6 (glucose). What are the mole fraction and molality of glucose in the solution? A. 0.0281 and 0.565m B. 0.0298 and 0.710m C. 0.972 and 19.52m D. 0.0290 and 0.630m 31. Suppose that we dissolve enough sugar in 100.0 g H 2O to cause the solution to have a freezing point of -3.20 C. How many grams of water must we add to the solution so that the freezing point will be - 1.00 C? For water, K f = 1.86 C/m. A. 3100 g B. 0.538 g C. 320 g D. 220 g E. 420 g 32. When we dissolve a 1.50 g-sample of a compound in enough solvent to give 800.0 ml of solution at 27 C, the osmotic pressure is 2.13 torr. What is the molar mass of the solute? A. 16.5 g/mol B. 1.65 x 10 4 g/mol C. 1.36 x 10-4 g/mol D. 9.10 x 10-5 g/mol E. 21.7 g/mol

Chem 120 Practice Final Winter 2014 8 of 14 33. Suppose that we had a solvent for which the solid-liquid equilibrium line sloped to the left instead of to the right. What effect would addition of a nonvolatile solute have on the boiling point and freezing point of the solution compared to that of the pure solvent? A. The freezing point would not change, but the boiling point would increase. B. The freezing point would decrease, and the boiling point would increase. C. The freezing point would increase, and the boiling point would decrease. D. The freezing point would increase, and the boiling point would increase. E. The freezing point would decrease, and the boiling point would decrease. 34. What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25 C? K b of water is 0.52 C/m. Assume the density of the solution is the same as that of pure water. A. 0.22 C B. 0.429 C C. 100.43 C D. 99.78 C E. 100.22 C 35. In which structure(s) below does the nitrogen have a formal charge of -1? A. I and IV B. I and III C. I, III, and IV D. II only E. I only

Chem 120 Practice Final Winter 2014 9 of 14 36. The structures below represent: H CH 3 CH 3 H CH 3 H H CH 3 A. enantiomers. B. conformational isomers. C. diastereomers. D. a single compound. E. meso forms. 37. Which compound is not a constitutional isomer of the others? A. III B. I C. IV D. II E. All of the above are isomers of each other. 38. The correct IUPAC name for the follow structure A. 2-Bromo-4-chloro-4,5-dimethylhexane B. 2-(2-Bromopropyl)-2-chloro-3-methylbutane C. 4-Bromo-2-chloro-2-isopropylpentane D. 5-Bromo-3-chloro-2,3-dimethylhexane E. 2-Bromo-4-chloro-4-isopropylpentane

Chem 120 Practice Final Winter 2014 10 of 14 39. Which functional group is not contained in prostaglandin E1? A. 3 alcohol B. Carboxylic acid C. 2 alcohol D. Alkene E. Ketone 40. Which of the following is the enantiomer of the following substance? A. 3 only B. Both 2 and 3 C. 2 only D. Both 1 and 2 E. 1 only

Chem 120 Practice Final Winter 2014 11 of 14 41. Compounds 1 and 2 are: A. diastereomers. B. constitutional isomers. C. not isomeric. D. identical. E. enantiomers. 42. How many stereocenters are present in estradiol? A. 5 B. 3 C. 7 D. 2 E. 8 43. Give the product(s) of the following reaction: CH2=CHCH3 + HCl? A. CH2(Cl)CH2CH3 B. CH2 (Cl)CH(Cl)CH3 + H2 C. CH3CH2CH3 + H2 D. CH3CH(Cl)CH3

Chem 120 Practice Final Winter 2014 12 of 14 44. What is the expected major production for the hydrogenation of an alkene? A. Dihaloalkane B. Alkane C. Haloalkane D. Alcohol E. Ether 45. What is produced from the polymerization of the compound below? A. B. C. D. 46. Give the product(s) of the following reaction in the presence of H2SO4, CH2=CHCH3 + H2O A. CH3CH(OH)CH3 B. no reaction occurs C. CH2(OH)CH(OH)CH3 + H2 D. CH3CH2CH3 + H2O2 47. Which of these contains a chiral carbon atom? A. CH3COOH B. CH2Cl2 C. CH3CH2CHBrCH3 D. E.

Chem 120 Practice Final Winter 2014 13 of 14 48. Hydrolysis of gives what products? a. H2O b. HCOOH c. CH3COOH d. CH3CH2OH e. CH3OH A. b and e B. a and c C. b and d D. c and d E. c and e 49. In a first-order reaction, A products, k = 0.0150 min -1. If [A] is 0.400 M initially, what will be the concentration of A after 2.00 h? A. 0.413 M B. 0.0661 M C. 2.42 M D. 0.388 M E. 6.34 x 10-3 M 50. The combustion of methane is represented by the equation CH4 + 2 O2(g) CO2(g) + 2 H2O(l) H = -890.3 kj What is q for the combustion of 105 L of CH4(g), measured at 23 C and 746 mmhg? A. -3.78 x 10 3 kj B. -9.35 x 10 4 kj C. +3.78 x 10 3 kj D. -210 kj E. -4.86 x 10 4 kj 51. A solution has a 1:4 mole ratio of pentane to hexane. The vapor pressures of the pure hydrocarbons at 20 C are 441 mmhg for pentane and 121 mmhg for hexane. What is the mole fraction of pentane in the vapor phase? A. 0.911 B. 0.549 C. 0.200 D. 0.507 E. 0.477

Chem 120 Practice Final Winter 2014 14 of 14 52. Find G f for C4H8. Its standard heat of formation is -0.13 kj/mol, and it has a standard molar entropy of 306 J/mol K. UPDATE: S f (C, graphite): 5.74 J/mol K and S f (H2(g)): 130.7 J/ mol K. A. -91.3 kj/mol B. 71.2 kj/mol C. 67.2 kj/mol D. -71.4 J/mol E. -51.7 kj/mol 53. Which of the following statements dealing with equilibria is incorrect? A. Catalysts have no effect on the value of the equilibrium constant. B. We do not need to know the mechanism of a reaction to write an equilibrium constant expression. C. At equilibrium in a reversible reaction, the rate of the forward reaction is equal to the rate of the reverse reaction. D. Kp and Kc are numerically equal if a reversible reaction involves only gases. E. The vapor pressure of a liquid can be expressed as an equilibrium constant. 54. Calculate the density, in g/l, of N2(g) at 715 torr and 98 C. A. 0.0309 g/l B. 0.00114 g/l C. 3.28 g/l D. 0.433 g/l E. 0.865 g/l 55. Calculate the heat capacity of a sample of radiator coolant if a temperature rise from -5 C to 142 C requires 932 J of heat. A. 6.80 J/ C B. 6.56 J/ C C. 0.158 J/ C D. 1.37 x 10 5 J/ C E. 6.34 J/ C

Chem 120 Practice Final Winter 2014 15 of 14 Answers: 1. A 13. A 25. E 37. E 49. B 2. B 14. C 26. A 38. D 50. A 3. E 15. E 27. D 39. A 51. E 4. C 16. C 28. B 40. D 52. B 5. E 17. E 29. B 41. B 53. D 6. C 18. B 30. A 42. A 54. E 7. C. 19. D 31. D 43. D 55. E 8. C. 20. B 32. B 44. B 9. A 21. E 33. B 45. D 10. C 22. B 34. E 46. A 11. E 23. C 35. E 47. C 12. D 24. D 36. D 48. E