Practice Final-Hale

Practice Final-Hale - The cobalt steel alloy is used in...

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Unformatted text preview: The cobalt steel alloy is used in what industry? Vanadium steel is an alloy where the two main elements are iron and what other metal? Which would you expect to be more acidic: CrO, Cr2 O3 or CrO 2 ? What is the shape of PCl5 ? What is the oxidation number of Co in [CoCl2 (NH3 )4 ]+? What is the coordination number of [CoCl2 (NH3 )4 ]+? Why does Li melt at a higher temperature than Na? Does the following complex form a low or high spin complex? [CrCl5 ]3- Explain the trends in atomic size with respect to the d-block elements. What oxides tend to be basic, acidic and amphoteric? (general trends not specific) Which Sn-O bond is the strongest? Which is more acidic? SnO 2 or SnO 4 Draw the mirror image of the following and state whether or not they are chiral. Cl Br F Cl F Br Br Cl F F Br Cl Br I Cl F I Cl Br I Cl F I F (Questions 1 and 2) Americium-241 is used in a number of smoke detectors; as this radioisotope decays it causes particles to ionize, conduct an electric current and thereby cause the alarm to buzz. The complete decay of Am 241 involves (successively) , , , , , , , , , , and production. 1. The isotope that undergoes the first particle emission is: a. U-233 b. Pa-233 c. Pa-239 d. Am-241 2. The isotope obtained when Am-241 has completed this decay sequence is: a. Pb-208 b. Re-205 c. Bi-209 d. Au-209 3. Species with unpaired electrons are paramagnetic and a. are seldom found in compounds of Groups IA, IIA, and IIIA. b. exist for at least one oxidation state of transition metals. c. are attracted to a magnetic field. d. Each of these statements is true. 4. Diamagnetic substances a. are attracted to a magnetic field because they contain unpaired electrons. b. are repelled by a magnetic field because they contain only paired electrons. c. become permanently aligned in a magnetic field. d. are not affected by a magnetic field. 5. Which of the following is paramagnetic? a) Zn(H2O)6+2 b) Co(NH3)6+3 d) Cu(H2O)6+ e) none of these c) Ni(CN)6-2 (square planar) 6. Of the following, the central metal ion most likely to form a colorless complex is a. Ti3+. b. Mn4+. c. Co2+. d. Zn2+. 7. The half-life of nickel-63 is 85 years. How old is a painting with an activity that is 3.5% of the steady-state rate for Ni-63? a. 0.027 yr b. 3.0 yr c. 410 yr d. 2400 yr 8. If water is replaced by ammonia in the [Fe(H 2O)6]3+ complex, the splitting of the dorbitals would a. increase. b. decrease. c. not be affected. d. increase for the iron complex, but might decrease with other metals. 9. Water gas, a commercial fuel, is made by the reaction of hot coke with steam. C(s) + H2O(g) ----> CO(g) + H 2(g) When equilibrium is established at 800C the concentrations of CO, H2, and H2O are 4.00 x 10-2 , 4.00 x 10-2, and 1.00 x 10-2 mole/liter, respectively. What is the value of G for this reaction at 800C? a) 109 kJ b) 43.5 kJ c) 193 kJ d) 16.3 kJ e) none of these 10. The color of transition metal complexes depends on the a. identity of the central atom. b. oxidation state of the central atom. c. identity of the ligand. d. Each of these statements is true. 11. A mixture of hydrogen and chlorine remains unreacted until it is exposed to ultraviolet light from a burning magnesium strip. Then the following reaction occurs very rapidly: H2 + Cl2 -----> 2HCl G = -45.54 kJ H = -44.12 kJ S = -4.76 J/K Select the statement below which BEST explains this behavior. a) The reactants are thermodynamically more stable than the products. b) The reaction has a small equilibrium constant. c) The ultraviolet light raises the temperature of the system and makes the reaction more favorable. d) The negative value for S slows down the reaction. e) The reaction is spontaneous by thermodynamics, but the reactants are kinetically stable. 12. A spontaneous chemical reaction is FAVORED by which of the following? a) increasing energy and increasing entropy b) lowering energy and increasing entropy c) increasing energy and decreasing entropy d) lowering energy and decreasing entropy 13. How many seconds will be required to deposit 6.23 g of Ag from a solution that contains Ag+ ions if a current of 0.35 A is used? a. 1.7 x 106 b. 1.6 x 104 c. 2.0 x 103 d. 2.1 x 102 14. All potentials in tables of standard reduction potentials are measured with respect to the standard hydrogen electrode as cathode, which is considered to have a potential of a. +1.76 V. b. +1.00 V. c. -1.00 V. d. 0.00 V. 15. In crystal field theory a. the approach of ligands to a central atom is described in terms of electrostatic interactions that result in a difference in the energies of d-orbitals on the central atom. b. the directions in which the d-orbitals point are no longer equivalent, and some of the orbitals are higher in energy than others. c. the movement of electrons across the small energy difference in d-orbitals accounts for the color of the complexes. d. All of the above are true. FOR THE NEXT THREE QUESTIONS CONSIDER THE FOLLOWING TABLE: a. dxy dxz dyz c. dxy dxz dx2-y2 dz2 dz2 dyz dx2-y2 b. dx2-y2 dxy dz2 dyz d. dx2-y2 dxy dz2 dxz dyz dxz 16. The d-orbital splitting in a tetrahedral complex would follow which pattern? 17. The d-orbital splitting in a square planar complex would follow which pattern? 18. The d-orbital splitting in an octahedral complex would follow which pattern? 19. The half-life of Sr-90 is 28.1 years. How long will it take a 10.0-g sample of Sr-90 to decompose to 0.10 g? a. 80. years 20. b. 140 years c. 190 years d. 2800 years If for the reaction, 2 Ag+(aq) + Co(s) --> 2 Ag(s) + Co2+(aq), E is 0.97 V when [Ag+] = 0.0025 M and [Co2+] = 0.032 M, then E for this reaction is a. 1.08 V. b. 1.05 V. c. 0.89 V. d. 0.86 V. 21. The reduction potentials for Au3+ and Ni2+ are +1.50 V and -0.23 V, respectively. What is G at 25C for the reaction below? 2Au3+ + 3Ni -----> 3Ni 2+ + 2Au a. -5.00 x 102 kJ b. +5.00 x 102 kJ c. -2140 kJ d. +1.00 x 103 kJ e. -1.00 x 103 kJ 22. Using the integrated second order rate law, derive the expression for the half life of a second order reaction: ln2 [A]o 1 a. t1/2 = b. t1/2 = c. t1/2 = k 2k k[A]o d. Only first order reactions have half-lives 23. A reaction can proceed by two different pathways. A plot of ln k versus 1/T is shown for the two pathways in the graph below. Which of the following statements is FALSE? I II ln k 1/T a) The activation energy for pathway II is the same as that for pathway I. b) At a given temperature the rate constant for pathway II will be SMALLER than that for pathway I. c) The change in kII for a given increase in temperature will be the same as the change in kI for the same increase in temperature. d) The A factors for the two pathways are the same. e) At all temperatures kI >> k II. 24. At a particular temperature, N2O5 decomposes according to a first-order rate law with a half-life of 3.0 s. If the initial concentration of N2O5 is 1.0 x 1016 molecules/mL, what will be the concentration in molecules/mLafter 10.0 sec? a) 9.9 x 1014 d) 6.3 x 103 b) 1.8 x 1012 e) 9.4 x 102 c) 7.3 x 109 25. The reaction 2NO + O2 2NO2 obeys the rate law -[O2]/t= k[NO]2[O2]. Which of the following mechanisms is consistent with the experimental rate law? a) NO + NO ----> N2O2 N2O2+ O2 ----> 2NO2 b) NO + O2 <--> NO3 NO3+ NO ---->2NO2 c) 2NO <--> N2O2 N2O2 ----> NO2+ O NO + O ----> NO2 d) O2+ O2----> O2+ O2* O2*+ NO ----> NO2+ O O + NO ----> NO2 e) none of these (slow) (fast) (fast equilibrium) (slow) (fast equilibrium) (slow) (fast) (slow); * indicates vibrationally excited oxygen (fast) (fast) 26. In which group do the atoms become larger in going down the group? a) group 1A d) group 7A b) group 4A c) group 5A e) groups 1A, 4A, 5A, and 7A 27. Which of the following processes result(s) in an increase in the entropy of the system? All systems are closed systems. I. II. Br2(g) Br2(l) IV. O2(298 K) O2(373 K) a) I b) II, V III. NaBr(s) Na+ (aq) + Br-(aq) V. NH3(1 atm, 298 K) NH3 (3 atm, 298 K) d) I, II, III, IV e) I, II, III, V c) I, III, IV 28. For the dissociation reaction of the acid HF HF H+ + FS is observed to be negative. The BEST explanation for this is: a) This is the expected result since each HF molecule produces two ions when it dissociates. b) Hydration of the ions produces the negative value of S. c) The reaction is expected to be exothermic and thus S should be negative. d) The reaction is expected to be endothermic and thus S should be negative. e) None of these can explain the negative value of S. 29. For the reaction A + B C + D, H = +40 kJ and S = +50 J/K. Therefore, the reaction at standard conditions is a) spontaneous at temperatures less than 10 K. b) spontaneous at temperatures greater than 800 K. c) spontaneous only at temperatures between 10 K and 800 K. d) spontaneous at all temperatures. e) nonspontaneous at all temperatures. 30. As O2(l) is cooled at 1 atm, it freezes at 54.5 K to form Solid I. At a lower temperature, Solid I rearranges to Solid II, which has a different crystal structure. Thermal measurements show that H for the I ---> II phase transition = -743.1 J/mol, and S for the same transition = -17.0 J/K mol. At what temperature are Solids I and II in equilibrium? a) 2.06 K b) 43.7 K c) 31.5 K d) 53.4 K e) They can never be in equilibrium because they are both solids. 31. Consider the process Rb(l) Rb(g) at 1 atm and 686C. Rubidium has a heat of vaporization of equal to 69.0 kJ/mol at its boiling point (686C). Calculate the value of Stotal., Ssurroundings, S, and G (in that order): a) All values are zero for this process b) 0, 69.0 kJ/mol, -71.9 J/K mol, 0 c) 71.9 J/mol K, -7.97 kJ/mol, 7.97 kJ/mol, 0 d) 0, -71.9 J/K mol, 71.9 J/mol K, 0 e) 0, 71.9 J/K mol, -71.9 J/mol K, 0 32. Given the following free energies of formation calculate Kp at 298 K for: C2H2(g) + 2H2(g) C2H6(g) C2H2(g) Gf = 209.2 kJ/mol C2H6(g) Gf = -32.9 kJ/mol a) 9.07 x 10-1 b) 97.2 31 c) 1.24 x 10 d) 2.74 x 1042 e) None of these is within a factor of 10 of the correct answer. (Questions 33-34) Consider the reaction of N2O5 at 25C for which the following data are relevant: 2N2O5(g) 4NO2(g) + O2(g) Substance Hf S N2O5 11.29 kJ/mol 355.3 J/K mol NO2 33.15 kJ/mol 239.9 J/K mol O2 ? 204.8 J/K mol 33. What is H for the reaction? a) 110.02 kJ b) 21.86 kJ d) 155.20 kJ e) -155.20 kJ What is S for the reaction (in J/K)? a) 89.5 b) 249.2 d) 249.2 e) -115.6 c) -21.86 kJ 34. c) 453.8 1. For the following reaction CuO(s) + H2 (g) ' Cu(s) + H2 O(g) at 298 K, H r = --87.0 kJ and S r = 47.0 J@ K --1 . Calculate G r at 150 K. __ A. __ B. __ C. __ D. __ E. --7140 kJ +94.0 kJ --80.0 kJ --94.0 kJ +80.0 kJ 2. Given: Cr(OH)3 (s) ' CrO4 2-- (aq), basic solution. How many electrons appear in the balanced half-reaction? __ A. __ B. __ C. __ D. __ E. 3 6 4 5 7 3. For the cell diagram Pt|H2 (g)|H + (aq) ~ Fe 3+ (aq),Fe 2+ (aq)|Pt which reaction occurs at the anode? __ A. __ B. __ C. __ D. __ E. 2H + (aq) + 2e-- Fe 2+ (aq) ' ' H2 (g) + e-- 2Fe2+ (aq) + 2H+ (aq) Fe3+ (aq) 2Fe 3+ (aq) + H2 (g) Fe 3+ (aq) + e-- H 2 (g) ' ' Fe2+(aq) ' 2H+ (aq) + 2e-- 4. Write the cell diagram for the reaction Cl2 (g) + 2Br-- (aq) ' 2Cl-- (aq) + Br2 (l) __ A. __ B. __ C. __ D. __ E. Pt|Br 2 (l)|Br -- (aq) ~ Cl -- (aq)|Cl 2 (g)|Pt Pt|Cl 2 (g)|Br -- (aq) ~ Cl -- (aq)|Br 2 (l)|Pt Pt|Cl -- (aq),Br -- (aq) ~ Br 2 (l)|Cl 2 (g)|Pt Pt|Br 2 (l)|Cl 2 (g) ~ Cl -- (aq)|Br -- (aq)|Pt Pt|Cl 2 (g)|Cl -- (aq) ~ Br -- (aq)|Br 2 (l)|Pt 1 5. Consider the following reaction: 2Ag+ (aq) + Cu(s) ' Cu2+ (aq) + 2Ag(s) If the standard reduction potentials of Ag+ and Cu2+ are +0.80 V and +0.34 V, respectively, calculate the value of E for the given reaction. __ A. __ B. __ C. __ D. __ E. --1.26 V +1.48 V --0.46 V +1.26 V +0.46 V 6. Which species will reduce Mn3+ but not Cr3+ ? __ A. __ B. __ C. __ D. __ E. Pb Zn Fe Al In 2 + 7. Which of the following is the strongest reducing agent? __ A. __ B. __ C. __ D. __ E. F-- Cr 2 + H2 Co2+ Fe2+ 8. If E for the disproportionation of Cu+ (aq) to Cu2+ (aq) and Cu(s) is +0.37 V at 25C, calculate the equilibrium constant for the reaction. __ A. __ B. __ C. __ D. __ E. 35.7 3.9 2.5 1.8 3.3 > > > > 107 4 101 4 106 101 2 9. If the standard free energy change for combustion of 1 mole of CH4(g) is --818 kJ/mol, calculate the standard voltage that could be obtained from a fuel cell using this reaction. __ A. __ B. __ C. __ D. __ E. +1.06 V +8.48 V --1.06 V +4.24 V +0.53 V 2 10. Consider the following cell: Ni(s)|Ni 2+ (aq, 0.200 M)~ Cl -- (aq, 0.0200 M)|Cl 2 (g, 0.500 atm)|Pt If the standard voltage for this cell is 1.59 V at 25C, calculate the voltage of this cell. __ A. __ B. __ C. __ D. __ E. +1.59 V +1.65 V +1.70 V +1.81 V 3 +1.48 V 11. Magnesium is produced by electrolysis of molten magnesium chloride. What are the products at the anode and cathode, respectively? __ A. __ B. __ C. __ D. __ E. Cl 2 (g) and Mg(l) Cl -- (aq) and MgO(l) O 2 (g) and Mg(l) Mg(l) and O2 (g) Cl 2 (g) and MgO(l) 12. If 306 C of charge is passed through a solution of Cu(NO3)2(aq), calculate the number of moles of copper deposited. __ A. __ B. __ C. __ D. __ E. 1.00 mol 2.00 mol 0.00159 mol 0.00317 mol 0.00634 mol 13. How long will it take to deposit 0.00470 moles of gold by electrolysis of KAuCl4 (aq) using a current of 0.214 amperes? __ A. __ B. __ C. __ D. __ E. 106 min 70.7 min 23.0 min 212 min 35.3 min 14. Which metal would be suitable to provide cathodic protection from corrosion for an iron bridge? __ A. __ B. __ C. __ D. __ E. None of the metals listed is suitable. Sn Pb Ni Cu 3 15. The products of the electrolysis of NaF(aq) are __ A. __ B. __ C. __ D. __ E. H 2 (g) and O2 (g). H 2 (g) and F2 (g). Na(l) and F2 (g). Na(l) and O2 (g). H 2 (g), OH-- (aq), and F2 (g). 16. Suppose that in starting a car on a cold morning a current of 125 amperes is drawn for 15 seconds from a standard lead-acid car battery. How many grams of Pb would be consumed? The atomic weight of lead is 207.19 g/mole. __ A. __ B. __ C. __ D. __ E. 8.05 2.01 0.018 0.036 4.02 17. A copper pipe in an older house was joined to another copper pipe by solder, which is an alloy of Sn and Pb. municipal water contains dissolved oxygen. What sort of corrosion would you expect to take place at the soldered joint in the plumbing system? __ A. __ B. __ C. __ D. __ E. The solder would behave as the cathode for the reduction of dissolved oxygen. No electrochemical corrosion reaction would occur. Copper would behave as the cathode for the reduction of dissolved oxygen and the solder would behave as the anode to yield soluble Sn2+(aq) and Pb2+(aq). Solder would behave as the cathode for the reduction of dissolved oxygen and the copper pipe would behave as the anode to yield soluble Cu2+(aq). Both the copper pipes and the solder at the joint would undergo anodic dissolution, while oxygen would be reduced in the interior core of the water column in the pipe. 18. The second law of thermodynamics can be stated in which one the following equivalent ways for a chemical reaction? __ A. __ B. __ C. __ D. __ E. H < 0 for a spontaneous process. S < 0 for a spontaneous process. G < 0 for a spontaneous process. -T S < 0 for a spontaneous process. all of the above statements are true 4 19. For the reaction 2NO2 (g) ' 2NO(g) + O2 (g) initial rate = k[NO 2 ]o 2 . For concentration in M and time in s, the units of the rate constant k are __ A. __ B. __ C. __ D. __ E. [email protected] [email protected] [email protected] s--1 M 2@ s--1 Br2 (g) ' 2NOBr(g) in NO and first-order in Br2 . If the initial concentrations of NO and M and 0.0100 M, respectively, the rate after 50% of the Br2 has percent of the initial rate? 20. The reaction 2NO(g) + is second-order Br 2 are 0.0200 reacted is what __ A. __ B. __ C. __ D. __ E. 12.5% 37.5% 18.8% 2.50% 50.0% 21. The rate of formation of NO2(g) in the reaction 2N2 O 5 (g) ' 4NO2 (g) + O2 (g) is 5.78 (mol NO2)@ L --1 @ s --1 . What is the rate at which N2O 5 is used? __ A. __ B. __ C. __ D. __ E. 2.89 (mol N2 O 5 )@ L --1 @ s -- 1 11.6 (mol N2 O 5 )@ L --1 @ s -- 1 5.78 (mol N2 O 5 )@ L --1 @ s -- 1 1.45 (mol N2 O 5 )@ L --1 @ s -- 1 0.723 (mol N2 O 5 ) @ L --1 @ s -- 1 22. If the rate of reaction increases by a factor of 9.6 when the concentration of reactant increases by a factor of 3.1, the order of the reaction with respect to this reactant is __ A. __ B. __ C. __ D. __ E. 2 1 3 4 1.5 5 23. For the reaction 2A + B ' products determine the rate law for the reaction given the following data: Initial Concentration, M A B 0.10 0.10 0.20 0.10 0.30 0.10 0.20 0.20 0.30 0.30 Initial Rate, [email protected] 2.0 8.0 1.8 8.0 1.8 x x x x x 10--2 10--2 10--1 10--2 10--1 __ A. __ B. __ C. __ D. __ E. 24. rate = k[A] rate = k[A][B] rate = k[A][B] 0 rate = k[A]2 rate = k[B]2 Given: SO2 Cl 2 (g) ' SO2 (g) + Cl2 (g) rate = k[SO 2 Cl 2 ] If 95% of the SO2Cl2 has reacted after 12 s, calculate the rate constant. __ A. __ B. __ C. __ D. __ E. 0.48 s-- 1 0.25 s-- 1 4.0 s-- 1 43 s-- 1 0.60 s-- 1 25. Calculate the rate constant at 53C for the reaction (NH3)5CoNC--R 3+(aq) + OH--(aq) ' (NH3)5CoNHCOR 2+(aq) if k = 5.8 > 106 M--1 @ s --1 at 25C and E a = 92 kJ/mol. __ A. __ B. __ C. __ D. __ E. > 107 M--1 @ s-- 1 1.4 > 108 M--1 @ s -- 1 9.0 > 109 M--1 @ s -- 1 7.3 > 107 M--1 @ s -- 1 2.5 > 107 M--1 @ s -- 1 1.3 26. Consider the mechanism: NO2(g) + F2(g) ' NO2F(g) + F(g) F(g) + NO2(g) ' NO2F(g) An intermediate in this reaction is __ A. __ B. __ C. __ D. __ E. slow fast There is no intermediate in this reaction. NO 2F(g) and F(g) F(g) NO 2F(g) NO 2 (g) 6 27. The rate law for the following mechanism is ClO--(aq) + H2O(l) i HOCl(aq) + OH--(aq) I--(aq) + HOCl(aq) ' HOI(aq) + Cl--(aq) HOI(aq) + OH--(aq) ' OI--(aq) + H2O(l) __ A. __ B. __ C. __ D. __ E. rate = k 1 k 2 K[ClO -- ][I -- ] rate = k 1 K[ClO -- ][I-- ][OH -- ] rate = k 1 K[ClO -- ][I-- ][OH -- ]-- 1 rate = k 1 K[ClO -- ][I -- ] rate = k 1 [I -- ][HOCl] K, fast k1, slow k2, fast 7 Name: __________________________ Date: _____________ 1. The maximum oxidation states for chromium and manganese are A) both +7. B) +7 and +8, respectively. C) +3 and +4, respectively. D) +5 and +6, respectively. E) +6 and +7, respectively. 2. What is the formula of the compound formed when potassium dichromate is dissolved in aqueous potassium hydroxide? A) K2CrO4 B) K2Cr2O7 C) CrO3 D) Cr(OH)3 E) Cr2O3 3. All of the following ligands are monodentate except A) ammine. B) cyano. C) aqua. D) carbonyl. E) oxalato. 4. What is the oxidation number of cobalt in [CoCl(NH3)5]Cl2? A) +4 B) +1 C) +6 D) +2 E) +3 5. What is the name of the complex [Cr(en)2(OH2)Cl]Cl2? A) diethylenediaminebis(aquachloro)chromium(III) chloride B) aquachlorobis(ethylenediamine)chromium(III) chloride C) chloroaquabis(ethylenediamine)chromate(III) chloride D) aquachlorobis(ethylenediamine)chromium(II) dichloride E) aquachloridebis(ethylenediamine)chromium(III) chloride Page 1 6. How many geometric isomers are possible for the complex ion [Co(NH3)3(OH2)3]3+? A) 4 B) 1 C) 0 D) 2 E) 3 7. Which of the following complexes is chiral? A) trans-[Cr(en)2Cl2]+ B) cis-[Cr(en)2Cl2]+ C) cis-[Cr(NH3)4Cl2]+ D) trans-[Cr(en)2(NH3)Cl]2+ E) [Co(OH2)3(NH3)3]3+ 8. Which of the following is expected to be the best oxidizing agent? A) Cu+(aq) B) Ti3+(aq) C) CrO42-(aq) D) VO2+ E) Cr2+(aq) 9. Which of the following would be the strongest acid in aqueous solution? A) Mg(OH2)62+(aq) B) V(OH2)62+(aq) C) Ni(OH2)62+(aq) D) Sc(OH2)63+(aq) E) Fe(OH2)62+(aq) 10. Which of the following complex ions has the largest d-orbital splitting energy? A) [Co(NH3)6]3+ B) [Co(CN)6]3C) [Co(ox)3]3D) [CoCl6]3E) [Co(OH2)6]3+ Page 2 11. Which of the following complex ions is colorless? A) [Cr(OH2)6]3+ B) [Ti(OH2)6]3+ C) [Ni(OH2)6]2+ D) [V(OH2)6]2+ E) [Zn(OH2)6]2+ 12. How many unpaired electrons are predicted for [Mn(CN)6]4-? A) 1 B) 2 C) 3 D) 5 E) 0 13. How many nucleons does boron-11 contain? A) 6 B) 10 C) 5 D) 11 E) 16 14. When an b particle is emitted, the atomic number A) increases by 4. B) decreases by 1. C) increases by 1. D) decreases by 4. E) increases by 2. 15. What nuclide undergoes a decay to produce the daughter nuclide radon-222 (Z = 86)? A) radium-226 B) thorium-230 C) polonium-222 D) protactium-230 E) uranium-236 Page 3 16. The nuclear equation for the disintegration of In-116 produces Sn-116 and A) a positron. B) helium-4. C) a neutron. D) gamma rays. E) an electron. 17. Bombarding 54Fe with a neutron results in emission of a proton and formation of A) 55Fe. B) 54Cr. C) 54Co. D) 54Mn. E) 49Ti. 18. Which of the following is most likely to undergo a decay? A) 24Na B) 47K C) 14C D) 232Th E) 3H 19. What is the element produced when 44Ti undergoes electron capture? A) Ar B) K C) Sc D) V E) Ca 20. Which of the following is most penetrating? A) a B) b C) b+ D) p E) n Page 4 21. When 214Pb decays as part of the 238U decay series, there are two a particles and four b particles lost starting with b emission from 214Pb. What is the final product? A) 207Pb B) 206Pb C) 210Bi D) 210Po E) 210Pb 22. The half-life of strontium-90 is 28.1 years. Calculate the percent of a strontium sample left after 100 years. A) 76% B) 0.34% C) 63% D) 82% E) 8.5% 23. A sample of a dish from an archaeological dig gave 18,500 disintegrations per gram of carbon per day. A 1.00-g sample of carbon from a modern source gave 22,080 disintegrations per day. If the decay constant of carbon-14 is 1.2 10-4 y-1, what is the age of the dish? A) 1500 y B) 8300 y C) 68000 y D) 640 y E) 30000 y 24. The nuclear binding energy for lithium-7 is the energy released in the nuclear reaction A) 31H + 7n 7Li B) 6Li + n 7Li C) 31H + 4b 7Li D) 31H + 4n 7Li E) 71H 7Li Page 5 25. Calculate the energy change when one 235U nucleus undergoes the fission reaction 235 U + n 142Ba + 92Kr + 2n The masses needed are 235U, 235.04 u; 142Ba, 141.92 u; 92Kr, 91.92 u; n, 1.0087 u. And there are 1.6605 x 10-27 kg/u. A) -3.2 10-28 J B) +1.8 10-10 J C) -1.7 10-10 J D) +2.9 10-11 J E) -2.8 10-11 J 26. What is the d-electron configuration of the tetrahedral complex ion [FeCl4]-? A) e2t3 B) e4t1 C) e5 D) e1t4 E) e3t2 27. A galvanic cell has in one compartment an aqueous solution of Cd+2 in contact with a Cd electrode. In the other compartment there is a 1.00M solution of Ni+2 in contact with a Ni electrode. The cell has an electromotive force of 0.240V at 25C. What is the concentration of Cd+2? The standard reduction potential of Ni2+ is -0.23 V and for Cd2+ it is -0.4V. A) 2 x 10-4 M B) 4 x 10-4 M C) 2 x 10-3 M D) 4 x 10-3 M E) none of the above 28. S2O8- (aq) + 3I- (aq) _ 2 SO4-2 (aq) + I3- (aq) This reaction has a rate constant of 4.79 M-1s-1. How long does it take for the reactant concentration to drop from 0.0720M to 0.0290M? A) 3.5 sec B) 4.3 sec C) 5.4 sec D) 6.8 sec E) 1.9 sec Page 6 29. What is the product that forms from the reaction K2O + P4O6 _ A) KPO2 B) KPO3 C) K2PO4 D) K3PO3 E) K3PO4 30. The standard reduction potential for the I2/I- electrode is +0.54 V, and the standard emf of the cell Pt(s)|I2(s)|I-(aq)|Ag+(aq)|Ag(s)| is +0.26 V at the same temperature. What is the standard reduction potential of the Ag+/Ag couple? A) +0.80 V B) -0.80 V C) +0.28 V D) -0.28 V E) none of these 31. The mechanism proposed for the reaction between nitric oxide and bromine is: Step 1: NO + Br2 NOBr2 (slow) (fast) Step 2: NOBr2 + NO NOBr + NOBr Write the rate law for the formation of NOBr A) Rate=k[NO][NOBr2] B) Rate=k[NO][Br2] C) Rate=k[NO]2[Br2] D) Rate=k[NOBr2]2 E) Rate=k[NO]2 32. Sodium azide is used to inflate protective air bags in automobiles. What mass of solid sodium azide is needed to provide 50.0L of N2 at 1.5 atm and 25C? MW sodium azide = 65.02 g/mol A) 133 g B) 138 g C) 289 g D) 298 g E) 66 g Page 7 33. The activity of a sample containing Carbon-14 is 4.7 Bq. Express this activity in millicuries. A) 1.27 x 10-5 MCi B) 1.74 x 1016 MCi C) 3.41 x 10-4 MCi D) 5.76 x 105 MCi E) 5.76 x 10-5 MCi 34. What are the decay products of 146C A) 146C + g B) 147N + 42He2+ C) 137N + 01e D) 147N + 0-1e E) It doesn't decay. 35. Which of the following reactions is the first step in forming plutonium in a nuclear reactor? A) 23892U + 10n ---> 23992U B) 23592U + 10n ---> 23692U C) 23892U ---> 23490Th + 42He D) 23892U ---> 23893Np + 0-1e E) 23592U ---> 23593Np + 0-1e 36. What is the following reaction called? 3H2 + N2 2NH3 A) Haber Process B) Ostwald Process C) Shift Reaction D) Rauschig Process E) Claus Process Page 8 37. Which of the following might be an initiation step in a chain reaction? A) Br2 + heat or light 2Br B) Br + H2 HBr + H C) H + Br2 HBr + Br D) Br + Br Br2 E) H + Br HBr . . . . . . . . . 38. Given: Ag+(aq) + e- Ag(s) Fe3+(aq) + e- Fe2+(aq) Cu2+(aq) + 2e- Cu(s) Which is the strongest reducing agent? A) Ag B) Cu2+ C) Cu D) Ag+ E) Fe2+ E = 0.80 V E = 0.77 V E = 0.34 V 39. If the standard potential for Ti3+(aq)/Ti2+(aq) is -0.37 V and the standard potential for Ti2+(aq)/Ti(s) is -1.63 V, calculate the standard potential for Ti3+(aq) + 3e- Ti(s). A) -1.19 V B) -0.40 V C) -2.00 V D) -1.26 V E) -1.21 V Page 9 40. Consider the following cell: Zn(s)Zn2+(aq, 0.100 M) m Cl-(aq, ? M)Cl2(g, 0.500 atm)Pt For this cell, E = 2.12 V and E = 2.27 V at 25C. Calculate the Cl-(aq) concentration in the cathode compartment. A) 1.2 10-1 M B) 4.3 10-5 M C) 2.9 10-3 M D) 1.5 10-3 M E) 6.5 10-3 M 41. For the reaction S2O82-(aq) + 3I-(aq) 2SO42-(aq) + I3-(aq), rate = k[S2O82-][I-]. When the reaction is followed under pseudo-first-order conditions with [S2O82-] = 200 mM and [I-] = 1.5 mM, the rate constant was 1.82 s-1. The second order rate constant, k, for the reaction is A) 1.21 103 M-1s-1. B) 6.07 103 M-1s-1. C) 9.10 M-1s-1. D) 1.37 10-2 M-1s-1. E) 1.82 M-1s-1. 42. The activation energy of a reaction is given by A) +(slope of a plot of lnk vs 1/T) R. B) -(slope of a plot of lnk vs 1/T) R. C) -R (slope of a plot of lnk vs 1/T). D) +(slope of a plot of lnk vs 1/T) R. E) -(slope of a plot of lnk vs 1/T) R. 43. Consider the following possible reactions: 1. B(OH)3(aq) + H2O(l) 2. SiH4(g) + H2O(l) (trace OH-(aq)) 3. CCl4(l) + H2O(l) 4. SiCl4(l) + H2O(l) Which of the reactions that occur are Lewis acid-base reactions? A) (3) and (4) B) (2) C) (1), (3), and (4) D) (1) E) (1) and (4) Page 10 44. What occurs when beryllium is added to aqueous sodium hydroxide? A) Be(OH)2(s) precipitates. B) Beryllium reacts to evolve hydrogen gas and form [Be(OH)4]2-(aq). C) Beryllium reacts to evolve hydrogen gas form [Be(OH2)6]2+(aq). D) O2(g) is produced. E) No reaction occurs because beryllium does not react in aqueous sodium hydroxide. 45. Calculate the emf for a Daniell Cell (E0 = 1.1 V ) with a Zn2+ concentration of 0.1M and a Cu2+ concentration of 0.1M. A) -2.2 V B) 0 V C) 1.1 V D) 2.0 V E) 2.2 V 46. Magnesium nitride dissolves in water to produce A) HNO3(aq) and MgO(s). B) N2(g) and MgO(s). C) NH3(g) and Mg(OH)2(s). D) Mg(NO3)2(aq). E) N2H4(l) and Mg(OH)2(s). 47. The geometry of PCl4+ is A) T-shaped. B) tetrahedral. C) seesaw. D) trigonal bipyramidal. E) trigonal pyramidal. 48. The oxoacids of Group 17 have the general formula HXOn where X is a halogen and n = 1 to 4. Which of the following is true? A) As the oxidation number of X increases, the strength of the acid decreases. B) As the oxidation number of X increases, the oxidizing strength of the acid increases. C) Only the oxoacids with oxidation number +1 are strong acids. D) The oxoacids with oxidation number +1 are reducing agents. E) The oxoacids with oxidation number +7 are weak oxidizing agents. Page 11 49. The products of the disproportionation of chlorine in water are A) HClO and O2 B) HClO and HCl C) ClO2 and H2 D) OH- and HCl E) HClO4 and HClO 50. The anhydride of phosphoric acid is produced by the reaction A) H3PO4(aq) HPO3(aq) + H2O(l). B) 2H3PO4(l) H4P2O7(l) + H2O(l). C) P4(s) + 3O2(g) P4O6(s). D) P4(s) + 5O2(g) P4O10(s). E) P4(g) + 3OH-(aq) + 3H2O(l) 3H2PO2-(aq) + PH3(g). Page 12 ...
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This note was uploaded on 08/27/2009 for the course CHEM 6 taught by Professor Hale during the Spring '09 term at CSU Northridge.

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