Experiment Initial [A] Initial [B] Initial Rate

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Edmund Townsend
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1 Chem 120 Practice Final Winter of The following are initial rate data for: A + 2 B C + 2 D Experiment Initial [A] Initial [B] Initial Rate 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] 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 x 10 4 B x 10 4 C. 670 D x 10 6 E x 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 B. 5.1 C. 17 D. 19 E. 25

2 Chem 120 Practice Final Winter of If the reaction 2H 2S(g) 2H 2(g) + S 2(g) is carried out at 1065 C, K p = 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 atm of H 2(g)? A atm B atm C atm D atm E 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 = at 400ºC mol HI was injected into a 2.00 L reaction vessel at 400ºC. Calculate the concentration of H 2 at equilibrium. A M B M C M D M E 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

3 Chem 120 Practice Final Winter of 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 L of nitric oxide at the same initial pressure and temperature? [ H f (NO) = 90.4 kj/mol; H f (NO 2) = kj/mol; H f (O 3) = kj/mol] A kj B kj C kj D kj E 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 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 = Calculate G for this reaction at 1500 C. A. 105 kj/mol B kj/mol C kj/mol D 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 = kj/mol, S = J/mol K; for N 2O 4(g), H f = 9.66 kj/mol, S = 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 = J/mol K. What is G for this process at 25 C? Si(s) + C(graphite) SiC(s) A kj/mol B x 103 kj/mol C kj/mol D kj/mol

4 Chem 120 Practice Final Winter of 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 = kj/mol For 3 CO2(g) C3O2(g) + 2 O2(g), G = kj/mol A kj/mol B kj/mol C kj/mol D 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, , and S in J/mol.K = 191.5, 237.7, and (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 , (b) , (c) B , (b) 213.7, (c) C , (b) , (c) D , (b) , (c) E , (b) (c)

5 Chem 120 Practice Final Winter of 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 K B. 298 K C. 280 K D K E. 318 K 18. What is the ph of a M solution of C 18H 21O 3N (codeine)? K b = 8.9 x A B C D E 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 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 M in diethylamine, (CH 3CH 2) 2NH, and M in diethylammonium chloride, (CH 3CH 2) 2NH 2Cl. (CH 3CH 2) 2NH + H 2O (CH 3CH 2) 2NH OH - K b = 6.9 x 10-4 A. ph = B. ph = 6.3 x 10-4 C. ph = 3.20 D. ph = E. ph = 10.80

6 Chem 120 Practice Final Winter of A 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 A B C D E When making ml of a buffer solution at ph 4.00 from M NaCHO 2 and 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 A L NaCHO 2 and 0.11 L HCHO 2 B L NaCHO 2 and 0.17 L HCHO 2 C L NaCHO 2 and 0.11 L HCHO 2 D L NaCHO 2 and L HCHO What is the ph of a solution prepared by adding 5.00 g NH 4Cl to ml of 0.40 M NH 3? The K b of NH 3 is 1.8 x A B C D A solution is prepared by diluting mole of a base to 1.00 liter. The solution has a ph = What is K b of the base? A. 2.2 x B C D E What is the OH - ion concentration in a M HNO 3 solution? A M B M C M D. Zero E 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.

7 Chem 120 Practice Final Winter of 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 mmhg and its density is g/cm 3 ; the vapor pressure of pure carbon tetrachloride is mmhg and its density is g/cm 3. If this solution is ideal, its total vapor pressure at 20 C is A mmhg. B mmhg. C mmhg. D mmhg. E mmhg. 29. A solution is prepared at 27 C from g C 6H 14 and 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 mmhg C mmhg D 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 and 0.565m B and 0.710m C and 19.52m D and 0.630m 31. Suppose that we dissolve enough sugar in g H 2O to cause the solution to have a freezing point of C. How many grams of water must we add to the solution so that the freezing point will be C? For water, K f = 1.86 C/m. A g B 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 ml of solution at 27 C, the osmotic pressure is 2.13 torr. What is the molar mass of the solute? A g/mol B x 10 4 g/mol C x 10-4 g/mol D x 10-5 g/mol E g/mol

8 Chem 120 Practice Final Winter of 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 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 C B C C C D C E 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

9 Chem 120 Practice Final Winter of 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

10 Chem 120 Practice Final Winter of 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

11 Chem 120 Practice Final Winter of 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 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

12 Chem 120 Practice Final Winter of 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.

13 Chem 120 Practice Final Winter of 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 = min -1. If [A] is M initially, what will be the concentration of A after 2.00 h? A M B M C M D M E x 10-3 M 50. The combustion of methane is represented by the equation CH4 + 2 O2(g) CO2(g) + 2 H2O(l) H = kj What is q for the combustion of 105 L of CH4(g), measured at 23 C and 746 mmhg? A x 10 3 kj B x 10 4 kj C x 10 3 kj D kj E 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 B C D E

14 Chem 120 Practice Final Winter of Find G f for C4H8. Its standard heat of formation is 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)): J/ mol K. A kj/mol B kj/mol C kj/mol D J/mol E 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 g/l B g/l C g/l D g/l E 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 J/ C B J/ C C J/ C D x 10 5 J/ C E J/ C

15 Chem 120 Practice Final Winter 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

2. Which of the following liquids would have the highest viscosity at 25 C? A) CH 3 OCH 3 B) CH 2 Cl 2 C) C 2 H 5 OH D) CH 3 Br E) HOCH 2 CH 2 OH

2. Which of the following liquids would have the highest viscosity at 25 C? A) CH 3 OCH 3 B) CH 2 Cl 2 C) C 2 H 5 OH D) CH 3 Br E) HOCH 2 CH 2 OH CHEF124 Mid Term Revision (Trimester 3, 2012/13) 1. Identify the dominant (strongest) type of intermolecular force present in (a) RbCl(s) ionic (b) NH 3 (l) - hydrogen bonding (c) Cl 2 (l) dispersion (d)