Fourth Exam – Form A Key 1. A 2. B 3. B 4. C 5. B 6. C 7. E 8. A 9. A 10. C 11. B 12. E 13. C6H12 C4H8O 14. [sodium ion] = 1.0 M [sulfate ion] = 0.5 M 15. 16. 2 Fe3+(aq) + 3 CO32−(aq) ⇌ Fe2(CO3)3(s) 17. 2 C5H6NO2 + 13 O2  10 CO2 + 6 H2O + 2 NO2 18. 3 I2(s) + 2 Al(s) ⇌ 6 I1−(aq) + 2 Al3+(aq) Eo = +2.20 V 19. a) CH2CH2OCH2CH2HOH b) carbon atom (yes or no) chemical formula a) no none b) yes Cr2S3 c) yes BaSO41. Which of the following substances would be most soluble in water? A) CH3OH B) CH3(CH2)8NH2 C) AgCl D) CH4 2. Consider the following five substances. How many of them would be strong electrolytes? i) CH3Br ii) C2H6 iii) H2O iv) NaOH v) CrCl3 A) one B) two C) three D) four E) all five 3. When dissolving these solids in water (note their values of Ksp), which is the best statement CaF2, Ksp = 4 x 10-11 BaF2, Ksp = 1 x 10-6 PbF2, Ksp = 3 x 10-8 A) BaF2 produces the fewest fluoride ions, while PbF2 produces the most fluoride ions B) CaF2 produces the fewest fluoride ions, while BaF2 produces the most fluoride ions C) BaF2 produces the fewest fluoride ions, while CaF2 produces the most fluoride ions D) CaF2 produces the fewest fluoride ions, while PbF2 produces the most fluoride ions E) PbF2 produces the fewest fluoride ions, while CaF2 produces the most fluoride ions 4. In which of the following is a sulfur atom in the +4 oxidation state? A) H2S B) H2SO4 C) H2SO3 D) H2S2O3 E) H2S2O4 5. Consider the energy diagram on the right for the chemical species G and J. Which of the following reactions would be extensive? A) G + J ⇌ G2+ + J2− B) G2+ + J ⇌ G + J2+ C) G2− + J ⇌ G + J2− D) Both A and B E) Both B and C 6. In the question above, which is the best oxidizing agent? A) G B) J C) G2+ D) G2− E) J2− 7. Which of the following unbalanced processes is a four electron oxidation? A) CO → CH3OH B) PH3 → P C) NO → NH3 D) ClO2 → ClO1− E) 2 H2O → O2 8. A galvanic electrochemical cell is constructed using the Zn2+/Zn and Pb2+/Pb half reactions. What reaction takes place at the anode? A) Zn → Zn2+ + 2 e1− C) Pb → Pb2+ + 2 e1− B) Zn2+ + 2 e1− → Zn D) Pb2+ + 2 e1− → Pb EGJ9. What is the oxidizing agent in this reaction? H2N2O2 + OH1− + Pb → N2 + HPbO21− + H2O A) H2N2O2 B) OH1− C) Pb D) N2 E) HPbO21− 10. Consider the Co2+ / Co redox couple, which has a reduction potential of −0.28 V. Select the best statement regarding the strengths of Co2+ and Co. A) Co2+ is a stronger oxidizing agent than Sn2+ while Co is a stronger reducing agent than Zn. B) Co2+ is a stronger oxidizing agent than Zn2+ while Co is a stronger reducing agent than Fe. C) Co2+ is a stronger oxidizing agent than Al3+ while Co is a stronger reducing agent than Cu. D) Co2+ is a stronger oxidizing agent than Fe3+ while Co is a stronger reducing agent than Ag. 11. In the molecule shown, which atom is most likely to act as a Lewis acid? A) oxygen #1 B) carbon #2 C) carbon #3 D) nitrogen #4 12. Which statement most accurately describes a Lewis acid/base reaction? A) Each reactant contributes one electron to form a new covalent bond B) A positive ion and negative ion come together to form a new ionic bond C) The Lewis acid provides two electrons to form a new covalent bond D) The Lewis acid provides two electrons to form a new ionic bond E) The Lewis base provides two electrons to form a new covalent bond PLACE YOUR ANSWERS FOR #13 – 19 DIRECTLY ON THIS EXAM 13. (5 each) In the spaces below, write the chemical formula for each of the molecules. O 14. (4 each) What is the concentration of each ion in a 0.50 M solution of sodium sulfate? [sodium ion] = [sulfate ion] = O COC NHHH CH2O HH123415. (18) For each combination of 0.1 M aqueous solutions listed, state (yes or no) whether a precipitate will form. IF YES, then provide the chemical formula of the solid. IF NO, write “None” for chemical formula. a) V(NO3)2 and Cu(C2H3O2)2 b) Cr(ClO4)3 and K2S c) Ba(NO3)2 and Li2SO4 16. (10) Write a balanced net equation for the reaction that occurs when 0.1 M aqueous solutions of FeCl3 and K2CO3 are mixed (be sure to include states of matter for this question). 17. (10) Write a balanced equation with integer coefficients for the complete combustion reaction of C5H6NO2. (For this question, you do not need to show states of matter.) 18. (10) Write a balanced net equation for the reaction that occurs when I2 is mixed with Al. Assume the presence of water so aqueous ions can be formed (be sure to include states of matter for this question). (4) What is the potential of this reaction? V 19. a) (8) Diagram the following reaction, using curved arrows to indicate electron movement. Lone pairs are not shown, but may need to be taken into account in your diagram. CH2CH2OCH2CH2HOH b) (2) Based on your diagram, which atom acts as the Lewis acid? (circle one) carbon atom oxygen atom (yes or no) chemical formula a) b)