Chemistry 106, Final Examination, Fall Semester 2010, Dec 15, AM-1PM.

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1 Chemistry 106, Final Examination, Fall Semester 2010, Dec 15, AM-1PM. 1. What element is being reduced in the following redox reaction? A) C B) O C) Mn D) H MnO4 (aq) + H2C2O4(aq) Mn2+(aq) + CO2(g) 2. Balance the following redox reaction if it occurs in acidic solution. What are the coefficients in front of Zn and H+ in the balanced reaction? Zn2+(aq) + NH4 + (aq) Zn(s) + NO3 (aq) A) Zn = 1, H + = 8 B) Zn = 1, H + = 4 C) Zn = 4, H + = 10 D) Zn = 2, H + = 4 E) Zn = 3, H + = 5 3. Identify the location of oxidation in an electrochemical cell. A) The anode. B) The cathode. C) The electrode. D) The salt bridge. E) The socket. Answer: A 4. Determine the redox reaction represented by the following cell notation. Mg(s) Mg2+(aq) Cu2+(aq) Cu(s) A) Cu(s) + Mg2+(aq) Mg(s) + Cu2+(aq) B) Mg(s) + Cu2+(aq) Cu(s) + Mg2+(aq) C) 2 Mg(s) + Cu2+(aq) Cu(s) + 2 Mg2+(aq) D) 2 Cu(s) + Mg2+(aq) Mg(s) + 2 Cu2+(aq) E) 3 Mg(s) + 2 Cu2+(aq) 2 Cu(s) + 3 Mg2+(aq)

2 5. What is the oxidizing agent in the redox reaction represented by the following cell notation? A) Sn(s) B) Ag+(aq) C) Sn2+(aq) D) Ag(s) E) Pt Sn(s) Sn2+(aq) Ag+(aq) Ag(s) 6. How many electrons are transferred in the following reaction? (The reaction is unbalanced.) A) 1 B) 2 C) 6 D) 3 E) 4 I2(s) + Fe3+(aq) Fe(s) + I (aq) 7. Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25 C. (The equation is balanced.) 3 Cl2(g) + 2 Fe(s) 6 Cl (aq) + 2 Fe3+(aq) Cl2(g) + 2 e 2 Cl (aq) Fe3+(aq) + 3 e Fe(s) E = V E = V A) V B) V C) V D) V E) V Answer: E

3 8. Use the tabulated half-cell potentials to calculate G for the following redox reaction. 2 Al(s) + 3 Mg2+(aq) 2 Al3+(aq) + 3 Mg(s) A) +4.1 x 102 kj B) +1.4 x 102 kj C) -2.3 x 102 kj D) -7.8 x 102 kj E) +6.8 x 102 kj 9. Use the tabulated half-cell potentials to calculate the equilibrium constant (K) for the following balanced redox reaction at 25 C. A) B) C) D) E) Pb2+(aq) + Cu(s) Pb(s) + Cu2+(aq) 10. Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25 C. A) V B) V C) V D) V E) V Mg(s) Mg2+(aq, 2.74 M) Cu2+(aq, M) Cu(s)

4 11. Which particle has the highest penetrating power? A) Alpha particle. B) Beta particle. C) Gamma particle. D) Positron emission. E) Electron capture. 12. Write a nuclear equation for the alpha decay of 95 Am. A) 95 Am He + 93 Np B) 95 Am 4 2 He Bk 95 Am 0-1 e 95 Am 0 +1 e C) + D) + E) 95 Am 1 0 n Cm 94 Pu Am Determine the identity of the daughter nuclide from the beta decay of 14 6 C. A) 14 7 N B) 10 4 Be C) 15 7 N D) 13 6 C E) 13 5 B 14. Determine the identity of the daughter nuclide from the positron emission of 13 7 N. A) 13 8 O B) 13 6 C C) 14 8 O D) 9 5 B E) 17 9 F

5 15. Identify the missing particle in the following nuclear equation: Pb 0-1 e +? A) Bi B) Tl C) Pb D) Pb E) Tl 16. Above what atomic number are there no stable isotopes of any element? A) 20 B) 92 C) 83 D) 40 E) The age of an ancient tree trunk is estimated using radiocarbon dating. If the trunk has a C-14 decay rate that is 34% of what it is in living plants, how old is the trunk? The half-life of C-14 is 5730 years. A) years B) years C) years D) years E) years 18. Write a nuclear equation to describe the neutron induced fission of Pu to form 36 Kr and Ce. Determine how many neutrons are produced in the reaction. A) 2 B) 0 C) 3 D) 1 E) 4

6 19. Determine the binding energy of an O-16 nucleus. The O-16 nucleus has a mass of amu. A proton has a mass of amu, a neutron has a mass of amu, and 1 amu is equivalent to 931 MeV of energy. A) 8.84 MeV B) 128 MeV C) 138 MeV D) 78.1 MeV E) 38.2 MeV 20. The following reaction represents what nuclear process? A) nuclear fusion B) alpha emission C) beta emission D) nuclear fission E) neutron capture 21. Give the number of covalent bonds that a carbon atom can form. A) 1 B) 2 C) 3 D) 4 E) Identify the formula for an alkene. A) CnH2n+2 B) CnH2n-2 C) CnH2n D) CnH2n-4 E) CnH2n+4

7 23. Which of the following compounds exhibits optical isomerism? A) CH3-CH2-CH3 B) CH3-CH2-CHBr-CH3 C) CH3-CHCl-CH3 D) CH3-CH2-CH2Br E) CH3-CH2-CBr2-CH3 24. How many of the carbons in the following compound are chiral center(s)? A) 0 B) 1 C) 2 D) 3 E) 4 or more 25. Name the following compound CH3-CH2-CH2-CH2-CH3 A) n-butane B) propane C) n-pentane D) hexane E) methane 26. Name the following compound CH2=CH-CH2-CH3 A) 1-butene B) 2-butene 3) 1-propene 4) 2-propene 5) 3-pentene

8 27. Name the following compound CH3-CH2-C C-CH2-CH3 A) 3-pentyne B) 2-butyne C) 3-pentene D) 3-hexyne E) 2-heptyne 28. Name the following compound. A) 3-ethyl-3-methylhexane B) 3-methyl-3-propylpentane C) 3-ethyl-3-propylbutane D) nonane E) 2-ethylheptane 29. Name the following compound. A) 2,2-diethylpenatane B) 2,2-diethylpentene C) 4-ethyl-4-methyl-5-hexene D) 3-ethyl-3-methyl-1-hexene E) 4-ethyl-4-methylhexane 30. Name the following compound. A) 3-butyl-3-propyl-1-pentyne B) 3-butyl-3-propyl-4-pentyne C) 3-ethyl-3-propyl-1-heptyne D) 5-ethyl-5-propyl-6-heptyne E) 3-ethyl-3-butyl-1-hexyne

9 31. Which of the following processes have a S > 0? A) CH3OH(l) CH3OH(s) B) N2(g) + 3 H2(g) 2 NH3(g) C) CH4(g) + H2O (g) CO(g) + 3 H2(g) D) Na2CO3(s) + H2O(g) + CO2(g) 2 NaHCO3(s) E) All of the above processes have a S > Consider the following reaction at constant P. Use the information here to determine the value of Ssurr at 298 K. Predict whether or not this reaction will be spontaneous at this temperature. N2(g) + 2 O2(g) 2 NO2(g) H = kj A) Ssurr = +223 J/K, reaction is spontaneous B) Ssurr = -223 J/K, reaction is not spontaneous C) Ssurr = J/K, reaction is spontaneous D) Ssurr = kj/k, reaction is not spontaneous E) Ssurr = J/K, it is not possible to predict the spontaneity of this reaction without more information. 33. Determine the equilibrium constant for the following reaction at 655 K. HCN(g) + 2 H2(g) CH3NH2(g) H (rexn) = -158 kj; S (rexn)= J/K A) B) 13.0 C) D) E) Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of Cl2 loss is M/s, what is the rate of formation of NOCl? A) M/s B) M/s C) M/s D) M/s E) M/s 2 NO(g) + Cl2(g) 2 NOCl(g)

10 35. Determine the rate law and the value of k for the following reaction using the data provided. 2 NO(g) + O2(g) 2 NO2(g) [NO]i (M) [O2]i (M) Initial Rate (M-1s-1) x x x 10-2 A) Rate = 57 M-1s-1[NO][O2] B) Rate = 3.8 M-1/2s-1[NO][O2]1/2 C) Rate = M-3s-1[NO]2[O2]2 D) Rate = M-2s-1[NO]2[O2] E) Rate = M-2s-1[NO][O2]2 36. The rate constant for a second-order reaction is 0.54 M-1s-1. What is the half-life of this reaction if the initial concentration is 0.27 M? A) 2.0 s B) 5.0 s C) 1.7 s D) 6.9 s E) 1.3 s 37. Which of the following compounds will be most soluble in ethanol (CH3CH2OH)? A) trimethylamine (N(CH3)3) B) acetone (CH3COCH3) C) ethylene glycol (HOCH2CH2OH) D) hexane (CH3CH2CH2CH2CH2CH3) E) None of these compounds should be soluble in methanol. 38. What mass (in g) of NH3 must be dissolved in 475 g of methanol to make a m solution? A) 2.02 g B) 4.94 g C) 1.19 g D) 8.42 g E) 1.90 g

11 39. A compound is found to have a molar mass of 598 g/mol. If 35.8 mg of the compound is dissolved in enough water to make 175 ml of solution at 25 C, what is the osmotic pressure of the resulting solution? A) 3.42 torr B) 6.36 torr C) 5.01 torr D) 5.99 torr E) 8.36 torr 40. What is the conjugate acid of H2PO4? A) HPO4 2 B) PO4 3 C) H3PO4 D) H3O+ E) OH 41. Determine the ph of a M C6H5CO2H M solution if the Ka of C6H5CO2H is 6.5 x A) 2.26 B) 4.52 C) D) 9.48 E) Determine the Ka of an acid whose M solution has a ph of A) B) C) 2.7 D) E) Which of the following is a Bronsted-Lowry acid? A) NH4 + B) CH4 C) NH2 D) NH3 E) Br2

12 44. Which of the following solutions is a good buffer system? A) A solution that is 0.10 M HC2H3O2 and 0.10 M LiC2H3O2 B) A solution that is 0.10 M HF and 0.10 M NaC2H3O2 C) A solution that is 0.10 M HCl and 0.10 M NH4 + D) A solution that is 0.10 M NaOH and 0.10 M KOH E) None of the above are buffer systems. 45. When titrating a weak monoprotic acid with NaOH at 25 C, the A) ph will be less than 7 at the equivalence point. B) ph will be equal to 7 at the equivalence point. C) ph will be greater than 7 at the equivalence point. D) titration will require more moles of base than acid to reach the equivalence point. E) titration will require more moles of acid than base to reach the equivalence point. 46. A 1.50 L buffer solution is M in HF and M in NaF. Calculate the ph of the solution after the addition of moles of solid NaOH. Assume no volume change upon the addition of base. The Ka for HF is A) 3.34 B) 3.46 C) 3.57 D) 3.63 E) Give the direction of the reaction, if K << 1. A) The forward reaction is favored. B) The reverse reaction is favored. C) Neither direction is favored. D) If the temperature is raised, then the forward reaction is favored. E) If the temperature is raised, then the reverse reaction is favored. 48. The equilibrium constant is given for one of the reactions below. Determine the value of the missing equilibrium constant. A) B) C) D) E) H2(g) + Br2(g) 2 HBr(g) Kc = HBr(g) H2(g) + Br2(g) Kc =?

13 49. The reaction below has a Kp value of 41. What is the value of Kc for this reaction at 400 K? A) B) C) 41 D) E) N2(g) + 3 H2(g) 2 NH3(g) 50. Consider the following reaction: CH4(g) + 2 H2S(g) CS2(g) + 4 H2(g) A reaction mixture initially contains 0.50 M CH4 and 0.75 M H2S. If the equilibrium concentration of H2 is 0.44 M, find the equilibrium constant (Kc) for the reaction. A) 0.23 B) C) 2.9 D) 10. E) 0.34

1022_3rd Exam_

1022_3rd Exam_1030521 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) For the following example, identify the following. H2O(l) H2O(g) A) a negative