General Chemistry Exam. Name:_________________ Student number: ____________________ 單選題(共 55 題,每題 2 分,合計 110 分)將答案寫在另外一張答案紙上。請利用本試卷空 白處計算。交卷時,試卷及答案紙都必須交。作弊以 0 分計,並送學校懲處。 Gas constant: R=8.31451 J/K.mol 或 0.08206 L.atm/K.mol 1. A 100-mL sample of water is placed in a coffee cup calorimeter. When 1.0 g of an ionic solid is added, the temperature decreases from 21.5°C to 20.8°C as the solid dissolves. For the dissolving of the solid a) H < 0 b) Suniv > 0 c) Ssys< 0 d) Ssurr > 0 e) none of these 2. A chemical reaction is most likely to be spontaneous if it is accompanied by a) b) c) d) e) increasing energy and increasing entropy. lowering energy and increasing entropy. increasing energy and decreasing entropy. lowering energy and decreasing entropy. none of these (a-d) 3. For the dissociation reaction of the acid HF HF(aq) H+(aq) + F–(aq) S is observed to be negative. The best explanation is: a) b) c) d) e) This is the expected result since each HF molecule produces two ions when it dissociates. Hydration of the ions produces the negative value of S. The reaction is expected to be exothermic and thus S should be negative. The reaction is expected to be endothermic and thus S should be negative. None of these can explain the negative value of S. 4. The heat of vaporization for 1.0 mole of water at 100°C and 1.0 atm is 40.6 kJ/mol. Calculate S for the process H2O(l) H2O(g) at 100°C. a) d) 109 J/K mol –406 J/K mol b) e) –109 J/K mol none of these c) 406 J/K mol 5. For a particular chemical reaction H = 5.5 kJ and S = –25 J/K Under what temperature condition is the reaction spontaneous? a) b) c) d) e) When T < –220 K. When T < 220 K. The reaction is spontaneous at all temperatures. The reaction is not spontaneous at any temperature. When T > 220 K. 1 6. For the reaction A + B C + D, H° = +40 kJ and S° = +50 J/K. Therefore, the reaction under standard conditions is a) b) c) d) e) 7-10. spontaneous at temperatures less than 10 K. spontaneous at temperatures greater than 800 K. spontaneous only at temperatures between 10 K and 800 K. spontaneous at all temperatures. nonspontaneous at all temperatures. Substance X has a heat of vaporization of 55.4 kJ/mol at its normal boiling point (423 C). For the process X (l) X (g) at 1 atm and 423 C calculate the value of: 7. Suniv. a) 0 b) 79.6 J/K mol c) 103 J/K mol d) -79.6 J/K mol e) -103 J/K mol c) 103 J/K mol d) -79.6 J/K mol e) -103 J/K mol 8. Ssurr a) 0 b) 79.6 J/K mol 9. S a) 0 b) 79.6 J/K mol c) 103 J/K mol d) -79.6 J/K mol e) -103 J/K mol 0 b) 79.6 J/K mol c) 103 J/K mol d) -79.6 J/K mol e) -103 J/K mol 10. G a) 11. Given the following free energies of formation: G°f C2H2(g) 209.2 kJ/mol C2H6(g) –32.9 kJ/mol calculate Kp at 298 K for C2H2(g) + 2H2(g) a) e) 9.07 10–1 b) 97.2 c) 1.24 1031 d) 2.72 1042 None of these is within a factor of 10 of the correct answer. 12. Calculate G° for H2O(g) + (1/2)O2(g) H2(g) + O2(g) 2H2(g) + O2(g) a) b) c) d) e) C2H6(g) H2O2 2H2O(g) H2O2(g) at 600. K, using the following data: Kp = 2.3 106 at 600. K Kp = 1.8 1037 at 600. K +140 kJ –220 kJ –290 kJ –350 kJ +290 kJ 2 13. Consider a weak acid, HX. If a 0.10 M solution of HX has a pH of 5.83 at 25°C, what is G° f ort hea c i d’ sdi s s oc i at i onr e ac t i ona t25° C? a) –61 kJ b) –30. kJ c) 0 d) 30. kJ e) 61 kJ 14–16. Consider the galvanic cell shown below (the contents of each half-cell are written beneath each compartment): Pt Cr 0.50 M Br2 0.20 M Cr3+ 0.10 M Br– The standard reduction potentials are as follows: Cr3+ + 3e– Cr(s) E° = –0.73 V Br2(aq) + 2e– 2Br– E° = +1.09 V 14. What is E° for this cell? a) 1.82 V b) 0.36 V c) 4.75 V d) 1.79 V e) 4.40 V d) 1.88 V e) 0.59 V 15. What is the value of E for this cell at 25°C? a) 2.21 V b) 1.76 V c) 2.12 V 16. Which of the following statements about this cell is false? a) b) c) d) e) This is a galvanic cell. Electrons flow from the Pt electrode to the Cr electrode. Reduction occurs at the Pt electrode. The cell is not at standard conditions. To complete the circuit, cations migrate into the left half-cell and anions migrate into the right half-cell from the salt bridge. 17. The galvanic cell described by Zn(s) Zn2+(aq) Cu2+(aq) Cu(s) has a standard cell 2+ potential of 1.101 volts. Given that Zn(s) Zn (aq) + 2e–has an oxidation potential of 0.762 volts, determine the reduction potential for Cu2+. a) –1.863 V b) 1.863 V c) –0.339 V d) 0.339 V e) none of these 18–19. The following questions refer to a galvanic cell that utilizes the following reaction (unbalanced): (AuCl4)–(aq) + Cu(s) Au(s) + Cl–(aq) + Cu2+(aq) 18. Given the following information determine the standard cell potential: a) Species Standard Reduction Potential (V) Au3+(aq) 1.498 Cu2+(aq) 0.339 1.159 V b) 1.837 V c) 1.979 V d) 1.462 V e) 2.102 V 3 19. Determine the number of electrons transferred during the reaction (balanced). a) 2 b) 3 c) 4 d) 6 e) 9 20. Choose the correct statement given the following information: Fe3+(aq) + e– Fe2+(aq) E° = 0.77 volt Fe(CN)63–+ e– Fe(CN)64– E° = 0.36 volt a) b) c) d) e) Fe2+(aq) is more likely to be oxidized than Fe2+ complexed to CN–. Fe3+(aq) is more likely to be reduced than Fe3+ complexed to CN–. Both a and b are true. Complexation of Fe ions with CN–has no effect on their tendencies to become oxidized or reduced. None of these is true. 21. Determine G° for a cell that utilizes the following reaction: Cl2(g) + 2Br–(aq) 2Cl–(aq) + Br2 (l) The standard reduction for the chlorine gas is 1.360 volts and the standard reduction for the bromine liquid is 1.077 volts. a) 471 kJ b) 236 kJ c) 27.3 kJ d) 54.6 kJ e) 82.5 kJ 22. Which of the following would be the best oxidizing agent? a) Cl2 b) Fe d) Na+ c) Na e) F– 23. Which of the following is the best reducing agent? a) Cl2 b) H2 d) Mg2+ c) Mg e) Cl– 24. Copper is electroplated from CuSO4 solution. A constant current of 4.00 amp is applied by an external power supply. How long will it take to deposit 1.00 102 g of Cu? The atomic mass of copper is 63.546. a) 21.1 h b) 10.0 min c) 1.60 days d) 11.2 s e) 2.91 h 25. Which type of battery has been designed for use in space vehicles? a) d) lead storage fuel cells b) e) alkaline dry cell silver cells c) mercury cells 26. Gold is produced electrochemically from an aqueous solution of Au(CN)2–containing an excess of CN–. Gold metal and oxygen gas are produced at the electrodes. How many moles of O2 will be produced during the production of 1.00 mole of gold? a) 0.25 b) 0.50 c) 1.00 d) 3.56 e) 4.00 4 27. What are the oxidation numbers of the central metal atom in the following coordination compounds? K3[Fe(CN)6], [Cr(NH3)4Br2]Br, [Ni(H2O)6]Cl2, Na2[TaF7] are a) d) 3, 3, 3, 5 –3, 1, 2, 5 b) e) 3, 3, 2, 7 3, 3, 2, 5 c) –3, 3, 2, 5 28. Which of the following complexes shows geometric isomerism? a) d) [Co(NH3)5Cl]SO4 K[Co(NH3)2Cl4] b) e) [Co(NH3)6]Cl3 none of these c) [Co(NH3)5Cl]Cl2 29. What is the sum of the geometric and optical isomers that the complex ion Co(en)2Cl2+ exhibits? a) 0 b) 1 c) 2 d) 3 e) 4 30. Which of the following ligands might give linkage isomers? a) NO2– b) SCN– c) H2NH2CCH2NH2 d) a and b e) a, b, and c 31. For the process Co(NH3)5Cl2+ + Cl– Co(NH3)4Cl2+ + NH3 what would be the ratio of cis to trans isomer in the product? a) 1:1 b) 1 : 2 c) 1 : 4 d) 4 : 1 e) 2 : 1 32. Which of the transition metals is the best conductor of heat and electric current? a) copper b) silver c) gold d) tungsten e) titanium c) Cu(CN)32– 33. Which of the following is paramagnetic? a) Zn(H2O)62+ d) Mn(CN)62–(strong field) b) Co(NH3)63+ (strong field) e) none of these 34. Calculate the total number of unpaired electrons in the following complex ions: Zn(OH2)62+, Ni(CN)42–(square planar), Co(NH3)63+ (strong field). a) 0 b) 1 c) 2 d) 3 e) 4 35. How many unpaired electrons are present in the tetrahedral complex [CoCl4]2–? a) 1 b) 2 c) 3 d) 4 e) 5 36. The complex ion Co(NH3)62+ (three unpaired electrons) is classified as: a) b) c) weak field strong field no way to tell 5 37. Which of the following complexes can exhibit optical isomerism? (en = H2NCH2 CH2 NH2 and is bidentate) a) d) cis–Co(NH3)4Cl2 Co(NH3)3Cl3 b) trans–Co(en)2Br2 e) none of these c) cis–Co(en)2Cl2 38. Which of the following are structural isomers? I. coordination isomers II. linkage isomers III. geometric isomers IV. optical isomers a) I, III b) II, IV c) I, III, IV d) II, III e) I, II 39. Which of the following statements is true about the octahedral complexes of Ni2+? a) b) c) d) Both strong- and weak-field complexes are diamagnetic. The strong-field complex is diamagnetic and the weak-field complex is paramagnetic. The strong-field complex is paramagnetic and the weak-field complex is diamagnetic. Both strong- and weak-field complexes are paramagnetic. 40. What transition metal has the combination of toughness, stretchability, and resilience that makes it ideal for use in bicycle frames? a) titanium b) platinum c) tungsten d) nickel e) aluminum 41. Give the number of geometrical isomers for the octahedral compound [MA2B2C2], where A, B, and C represent ligands. a) 1 b) 2 c) 3 d) 5 e) none of these 42. Ethylenediamine (en) is a bidentate ligand. What is the coordination number of cobalt in [Co(en)2Cl2]Cl? a) four b) five c) seven d) eight e) six 43. Name the following: CH3 CH3CH2CCH3 CH2CH3 a) c) n-heptane 3,3-dimethylpentane b) d) 2-methyl-2-ethylbutane 2,2-diethylpropane 6 44. Name the following: a) 2,2,3,5-tetramethyl-7-propyl-7-t-butyldecane b) c) d) e) 6-propyl-2,6-di-t-butylnonane 2,2,5,7,8,8-hexamethyl-3,3-dipropylnonane isonanane none of these 45. A student gave a molecule the following name: 2-methyl-4-t-butylpentane However, the teacher pointed out that, although the molecule could be correctly drawn from this name, the name violates the IUPAC rules. What is the correct (IUPAC) name of the molecule? a) c) e) 2-t-butyl-4-methylpentane 2,4,5,5-tetramethylhexane none of these (a-d) b) d) 2,2,3,5-tetramethylhexane 1-sec-butyl-1,2,2-trimethylpentane 46. How many isomers are there of "dichloroethene"? a) 2 b) 3 c) 4 d) 5 e) 6 47. Chemical reactions involving alkanes in which hydrogen atoms are removed and the product is an unsaturated hydrocarbon are called a) b) c) d) e) combustion reactions. dehydrogenation reactions. substitution reactions. addition reactions. polymerization reactions. 7 48. Name the following: a) c) e) 2-chloro-3-chloro-cis-2-butene 2,3-dichloro-trans-2-butene 2,3-dichloro-1-methyl-propene b) d) 2,3-dichloro-cis-2-butene 1-chloro-1-methyl-2-chloro-propene 49. Pick the optically active molecule among the following: a) d) H H H C C H H HO H H C C HO H H H HO H H C O H H b) c) H C C Cl H H H e) none of these 50. Which of the following is optically active (i.e., chiral)? a) d) HN(CH3)2 2-chlorobutane b) e) CH2Cl2 3-chloropentane c) 2-chloropropane 51. If you were to heat pentanoic acid and 2-butanol with a strong acid, you would most likely discover in your flask: a) a ketone b) an ester c) an amine d) an alkane e) an aldehyde 52. Consider the polymer drawn below: CH3 C CH3 CH2 C CH3 CH3 CH2 C CH3 CH2 n CH3 What monomer(s) is (are) needed to produce the above polymer? a) CH2 = CH2 and CH3CH = CH2 b) CH2 = C(CH3)2 c) CH3CH = CHCH3 d) CO and CH2 = CH2 e) none of these 8 53. The structures of proteins are partially determined by the order of various amino acids in the macromolecule. This level of structural determination is known as a) b) c) d) e) primary structure. secondary structure. tertiary structure. quaternary structure. order of bases. 54. The condensation product of two amino acids is a(n) a) b) c) d) e) peptide. ketone. ether. ester. alcohol. 55. How many possible sequences can be made for a polypeptide with six different amino acids? a) b) c) d) e) 6 36 64 720 none of these (a-d) 9