CHEM 102 Winter 19 Final Exam (A) Questions and Answers,100% CORRECT

CHEM 102 Winter 19 Final Exam (A) Questions and Answers Potentially useful data: x  1 atm = 760 torr = 760 mm Hg 2 a [A]t = – kt + [A]o ∆G° = ∆H° – T ∆S° ln[A]t = – kt + ln[A]o ∆G = ∆G° + RT ln Q 1/[A]t = kt +1/[A]o ∆G° = – RT ln K First order half-life: t1/2 = ln2 / k ∆G° = – nFE° pH  pKa  log base acid  E  E  R T ln Q n F R = 8.314 J mol-1 K-1 F = 96500 C/mol e- 1. Please choose the letter “A” as your answer for this question. 2. Which of the following substances can be used as a monomer for addition polymerization? a) H2C=CHBr b) H2C=C-CH=O c) H3C-CH2-CH3 d) HCŁC-CH2-CH3 e) all except c) 3. Which of the following reactions has a negative S°? a) 2 H2 (g) + O2 (g)  2 H2O (g) b) BaF2 (s)  Ba2+ (aq) + 2 F (aq) c) CH3OH (aq)  CH3OH (l) d) both a) and c) e) All of the above. 4. How many C-H bonds are present in a molecule of cyclohexane? a) 8 b) 10 c) 12 d) 14 e) 16 Page 1 of 13 5. Which is the correct name for the following compound? a) 3-methyl-2-pentene b) 2-ethylbutane c) 2-ethyl-2-butene d) 3-methyl-3-pentene e) 3-methylpentane 6. What would be a correct expression of the overall reaction rate for the production of ammonia? N2 (g) + 3 H2 (g) → 2 NH3 (g) a) rate = + 2∆[NH3]/∆t b) rate = - 3∆[H2]/∆t c) rate = + 2/3 ∆[NH3]/∆t d) rate = - 1/2 ∆[N2]/∆t e) rate = - 1/3 ∆[H2]/∆t 7. Estimate the [H3O+] in a buffer that consists of 0.30 M HCOOH (Ka = 1.7 × 10–4) and 0.20 M HCOONa. a) 1.1 × 10–4 M b) 2.6 × 10–4 M c) 4.3 × 10–4 M d) 6.7 × 10–5 M e) 7.6 × 10–5 M 8. Which substance exhibits ONLY London dispersion intermolecular forces between its molecules? a) HF b) SiCl4 c) PF3 d) OF2 e) CH3Cl 9. Which statement is FALSE about a compound A that has the structure below? CH3 H3C C H H C CH CH2 CH3 a) Methylcyclohexane is a structural isomer of compound A. b) Compound A is unsaturated. c) Compound A is a hydrocarbon. d) There are two possible, distinct 3-D orientations of the C-H bonds around the C=C bond. e) The addition of two hydrogen atoms to compound A would convert this compound into an alkyne. 10. Determine the molar solubility of Al(OH)3 in a solution containing 0.05 M AlCl3. Ksp for Al(OH)3 is 1.3 × 10-33. a) 2.6 × 10-9 M b) 5.2 × 10-31 M c) 9.9 × 10-12 M d) 1.04 × 10-29 M e) 6.5 × 10-35 M 11. Which class of compounds below could be associated with geometric isomers? a) alkenes b) alkynes c) alkylbenzenes d) alkyl ethers e) alkanes 12. The cell notation for a voltaic cell constructed with copper and silver is shown below. Cu (s) | Cu2+ (aq) || Ag+ (aq) | Ag (s) Which process occurs at the cathode? a) Ag+ (aq) + e–  Ag (s) b) Cu2+ (aq) + 2e–  Cu (s) c) Ag (s)  Ag+ (aq) + e– d) Cu (s)  Cu2+ (aq) + 2e– e) Cu (s) + 2 Ag+ (aq)  Cu2+ (aq) + 2 Ag (s) 13. Rank the following substances in order of increasing (that is, from lowest to highest) solubility in water. butane methyl propanoate butanoic acid a) butane < butanoic acid < methyl propanoate b) butanoic acid < butane < methyl propanoate c) methyl propanoate < butanoic acid < butane d) butane < methyl propanoate < butanoic acid e) Not enough information to rank. 14. A solution containing more than the equilibrium amount of dissolved solute is called . a) unsaturated b) concentrated c) supersaturated d) saturated e) None of the above. 15. Which of the following molecular formulas could indicate a CYCLOALKENE? a) C6H6 b) C5H10 c) C4H10 d) C4H6 e) C5H12 16. Which could be a good indicator for the titration of a weak acid with a strong base? a) methyl orange (transition range pH 3.1 to 4.4) b) methyl purple (transition range pH 4.8 to 5.4) c) bromophenol blue (transition range pH 3.0 to 4.6) d) methyl red (transition range pH 4.0 to 6.3) e) None of the above. 17. The solubility of Mn(OH)2 is 2.2 × 10–5 M. What is the Ksp of Mn(OH)2? a) 1.1 × 10–14 M b) 4.3 × 10–14 M c) 2.1 × 10–14 M d) 4.8 × 10–10 M e) 2.2 × 10–5 M 18. Which of the following processes is non-spontaneous? a) the transfer of heat from a warm object to a cold one b) the melting of ice at 25 oC c) the decomposition of water into H2(g) and O2(g) gas d) the freezing of water at -5 oC e) the dissolution of table salt in water 19. Consider the overall reaction below for an electrochemical cell with Ecell = 2.350 V at 200.0 °C. G at this temperature is and the cell is . 2 Na (l) + FeCl2 (s)  2 NaCl (s) + Fe (s) a) + 226.8 kJ; spontaneous b) + 453.5 kJ; non-spontaneous c) – 226.8 kJ; non-spontaneous d) – 453.5 kJ; spontaneous e) – 453.5 kJ; at redox equilibrium 20. Which substance below has the highest vapor pressure at the same temperature? a) CH3-OH (l) b) CH3-O-CH3 (l) c) H2O (l) d) C20H44 (l) e) CH3-COOH (l) 21. Consider the chemical equation below. Which molecule contains the reducing agent? CH4 + O2 → CO2 + H2O a) O2 b) CO2 c) H2O d) CH4 e) None of the above. This is not a redox process. Use the phase diagram below to answer questions 22 and 23: 22. Each point in the phase diagram above represents a different combination of temperature and pressure for a substance. What action could result in the vaporization of the substance? a) decreasing the pressure of the substance at point 4 b) increasing the pressure of the substance at point 5 c) increasing the temperature of the substance at point 6 d) decreasing the pressure of the substance at point 2 e) decreasing the temperature of the substance at point 1 23. Choose the TRUE statement. a) The triple point would be at a higher temperature than point 4. b) The 6 to 1 transition would be endothermic. c) The 2 to 5 transition would be exothermic. d) The 3 to 2 transition would increase the substance entropy. e) The intersection of the three curves shows the critical point. 24. Kinetics studies for the reaction below showed that the reaction became three times faster when the concentration of B was tripled at the same temperature. The reaction is order in B. A + B → P a) one-half b) first c) zero d) second e) third 25. Consider a reaction that has a negative ∆H and a positive ∆S. Predict the spontaneity of this process. a) spontaneous only at high temperatures b) spontaneous at all temperatures c) non-spontaneous at all temperatures d) non-spontaneous only at high temperatures e) not enough information 26. The cell shown below has Eocell = + 1.41 V. Al(s) | Al3+(aq) || Ni2+(aq) | Ni(s) The concentration of Al3+(aq) is 0.050 M and the concentration of Ni2+(aq) is 2.0 M. Estimate the cell potential at 25 oC. a) +1.34 V b) +1.44 V c) -1.41 V d) +1.38 V e) +1.48 V 27. The second-order decomposition of HI has a rate constant of 1.80 × 10-3 M-1s-1. If the initial concentration of HI is 4.78 M, estimate [HI] after 27.3 s. a) 3.87 M b) 0.258 M c) 4.55 M d) 2.20 M e) 2.39 M 28. Consider the following reactions at equilibrium. Based on Le Châtelier's principle, identify the reaction for which an increase in pressure at constant temperature would NOT temporarily change the partial pressures of reactants and products. a) N2 (g) + 3 H2 (g) 4 2 NH3 (g) b) N2O4 (g) 4 2 NO2 (g) c) N2 (g) + 2 O2 (g) 4 2 NO2 (g) d) 2 N2 (g) + O2 (g) 4 2 N2O (g) e) N2 (g) + O2 (g) 4 2 NO (g) 29. What are the STRONGEST attractive interactions between molecules of H2S? a) dipole-dipole forces b) covalent bonds c) ion-dipole forces d) London (dispersion) forces e) hydrogen bonding 30. How much energy is required to heat 87.1 g acetone, CH3-CO-CH3, from a solid at -154.0 oC to a liquid at - 42.0 oC? The following physical data may be useful: boiling point acetone = 56.1 oC melting point acetone = - 95.0 oC heat of vaporization for acetone = 539 J/g heat of fusion for acetone = 125 J/g specific heat of acetone liquid = 2.16 J/g oC specific heat of acetone solid = 1.65 J/g oC a) 8.48 kJ b) 18.5 kJ c) 29.3 kJ d) 32.2 kJ e) 9.97 kJ 31. A 25.0 mL sample of CH3COOH(aq) is titrated with a 0.175 M NaOH(aq). When 37.5 mL of the base are added, the equivalence point is reached. Estimate the concentration of CH3COOH(aq). a) 0.119 M -4 b) 1.83 × 10 M c) 0.175 M d) 0.365 M e) 0.263 M 32. What is the pH of 0.1 M HCl(aq)? a) 0.05 b) 1 c) 10-1 d) 10-2 e) 2 33. The equilibrium shown by the chemical equation below is characterized by Kp = 7.52 × 10-2 at 480.0 °C. 2 H2O (g) + 2 Cl2 (g) 4 HCl + O2 (g) Estimate the value of Kp for the reaction shown by the following equation, at the same temperature. 2 HCl (g) + 1/2 O2 (g) H2O (g) + Cl2 (g) a) 0.274 b) 3.65 c) 13.3 d) - 3.76 × 10-2 e) 5.66 × 10-3 34. Nitrogen dioxide decomposes to nitric oxide and oxygen, as shown by the equation below: 2 NO2 → 2 NO + O2 At 300 °C, [NO2] drops from 0.01 to 6.5 × 10-3 M in 100 s. Estimate the rate of appearance of O2 during this period of time. a) 1.8 × 10-5 M/s b) 3.5 × 10-5 M/s c) 7.0 × 10-5 M/s d) 3.5 × 10-3 M/s e) 7.0 × 10-3 M/s 35. Calculate the pH of a solution that is 0.210 M in nitrous acid, HNO2 (Ka = 4.50 × 10-4) and 0.290 M in potassium nitrite, KNO2 . a) 3.49 b) 5.21 c) 13.9 d) 10.5 e) 4.56 36. The solubility of polar solids in water generally DECREASES when . a) more H-bonds form between solute and solvent b) temperature decreases c) temperature increases d) fewer H-bonds form between solute and solvent e) both b) and d) 37. Use the experimental data below to determine the rate law for the following reaction: S O2 + 3 I–(aq)  2SO2 + I3– Experiment [S2O82-]0 [I–]0 Initial Rate 1 0.038 0.060 1.4 × 10–5 M/s 2 0.076 0.060 2.8 × 10–5 M/s 3 0.076 0.030 1.4 × 10–5 M/s a) rate = k[S2O82-][I-]3 b) rate = k[S2O82-] c) rate = k[S O 2-]2[I-]2 d) rate = k[I-] e) rate = k[S O 2-][I-] 38. How many electrons are transferred in the reaction indicated by the chemical equation below? 3 Mg (s) + N2 (g)  Mg3N2 (s) a) 2 b) 3 c) 6 d) 4 e) None. This is not a redox reaction. 39. Consider the following reaction: 2 A + B + 2 C → P If the reaction is zero order with respect to A, second order with respect to B, and first order with respect to C, what are the units of measure for the rate constant? Assume the time measured in seconds. a) M-2 s-1 b) M-1 s-1 c) s-1 d) M-3 s-1 e) M s-1 40. Which is the WEAKEST acid and why? a) HF, since fluorine is the most electronegative, but H-F is the shortest bond. b) HBr, since bromine has the largest volume, but the H-Br bond is shorter. c) HCl, since chlorine is more electronegative, but the H-Cl bond is stronger. d) HI, since iodine is the least electronegative, but the H-I bond is the weakest bond. e) All of the above acids have the same strength, since hydrogen directly bonds to a halogen. 41. What would be the standard cell potential for a spontaneous electrochemical cell constructed with the two metals below? Cu2+(aq) + 2e–  Cu(s) E° = 0.34 V Sn4+(aq) + 2e–  Sn2+(aq) E° = 0.13 V a) 0.47 V b) 0.21 V c) – 0.21 V d) – 0.47 V e) 0.42 V 42. What molar ratio of CH3COOH to CH3COONa should be used to prepare a buffer solution with a pH of 4.00 ± 0.02? The pKa of CH3COOH is 4.75. a) 0.18 b) 0.84 c) 1.19 d) 5.50 e) 0.10 43. What type of polymer is represented by the following repeating segment? O C a) polyamide (condensation polymer) b) polyester (condensation polymer) c) polyether (addition polymer) d) polyester (addition polymer) e) polyamide (addition polymer) CH22CH22 O C OCH22CH22O 44. What mass of CuBr2 is needed to prepare 750 mL of 1.25 M CuBr2 (aq)? a) 134 g b) 938 g c) 372 g d) 209 g e) The density of the solution is needed to determine. 45. Estimate the percent concentration by mass of 0.711 M CsCl (aq) that has a density of 1.091 g/mL. a) 1.10 % b) 0.387 % c) 11.0 % d) 0.651 % e) 0.775 % 46. What would be best to use to make a buffer solution with a neutral pH? a) an equimolar mixture of a strong acid and a strong base b) an equimolar mixture of an extremely weak acid and an extremely strong base c) a weak acid with a Ka near 1.00  10-7 and its conjugate base d) a weak acid with a pKa near -7 and its conjugate base e) None of the above. 47. What happens to the solubility equilibrium of 0.1 M Ca(OH)2 if HCl is added? The equilibrium will . a) shift to the right because the [ - b) shift to the left because the [ - c) not shift, since HCl does not appear in the Ksp expression d) shift to the right because both the [Ca2+] and [OH- e) shift to the left because the [ - 48. Consider 1 L of a buffer solution, in which [HF] = 0.10 M and [NaF] = 0.050 M. Which action will result in exceeding the buffer's capacity? a) adding 0.060 moles of HCl b) adding 0.20 moles of NaOH c) adding 0.050 moles of NaOH d) adding 0.01 moles of HCl e) both a) and b) 49. According to the Second Law of Thermodynamics, the . a) energy of the universe is constant b) entropy of the universe is constant c) enthalpy of the universe is constant d) energy of the universe is decreasing e) entropy of the universe is increasing 50. What indicates the presence of WEAK intermolecular forces in a liquid? a) high heat of vaporization b) high critical temperature c) low vapor pressure d) high volatility e) high boiling point 51. A reaction is described by the following rate law: rate = k[A][B]2[C]1/2 If [A] is doubled, [B] is decreased by a half, while [C] and the temperature stay constant, the reaction rate will decrease by a factor of . a) 4 b) 8 c) 2 d) 5.5 e) 3.5 chem102w19_final exam A Answer Section MULTIPLE CHOICE 1. ANS: A PTS: 0 2. ANS: E PTS: 1 3. ANS: D PTS: 1 4. ANS: C PTS: 1 5. ANS: A PTS: 1 6. ANS: E PTS: 1 7. ANS: B PTS: 1 8. ANS: B PTS: 1 9. ANS: E PTS: 1 10. ANS: C PTS: 1 11. ANS: A PTS: 1 12. ANS: A PTS: 1 13. ANS: D PTS: 1 14. ANS: C PTS: 1 15. ANS: D PTS: 1 16. ANS: E PTS: 1 17. ANS: B PTS: 1 18. ANS: C PTS: 1 19. ANS: D PTS: 1 20. ANS: B PTS: 1 21. ANS: D PTS: 1 22. ANS: A PTS: 1 23. ANS: B PTS: 1 24. ANS: B PTS: 1 25. ANS: B PTS: 1 26. ANS: B PTS: 1 27. ANS: A PTS: 1 28. ANS: E PTS: 1 29. ANS: A PTS: 1 30. ANS: C PTS: 1 31. ANS: E PTS: 1 32. ANS: B PTS: 1 33. ANS: B PTS: 1 34. ANS: A PTS: 1 35. ANS: A PTS: 1 36. ANS: E PTS: 1 37. ANS: E PTS: 1 38. ANS: C PTS: 1 39. ANS: A PTS: 1 40. ANS: A PTS: 1 41. ANS: B PTS: 1 42. ANS: D PTS: 1 43. ANS: B PTS: 1 44. ANS: D PTS: 1 45. ANS: C PTS: 1 46. ANS: C PTS: 1 47. ANS: A PTS: 1 48. ANS: E PTS: 1 49. ANS: E PTS: 1 50. ANS: D PTS: 1 51. ANS: C PTS: 1