Name (Print) Section # or TA. 1. You may use a crib sheet which you prepared in your own handwriting. This may be

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1 Name (Print) Section # or TA 1. You may use a crib sheet which you prepared in your own handwriting. This may be one 8-1/2 by 11 inch sheet of paper with handwriting only on one side. 2. You may use a calculator. 3. Please place all books, bags, hats, etc. under the table before you begin the Exam. 4. You must work alone. Give or take no assistance from other students. Recall the Georgia Tech Honor Code. I pledge my honor that I have not violated the Honor Code during this examination. Signed 5. Show your Buzz Card when you turn in your completed exam. 6. Multiple Choice, no partial credit. 7. You may remove the last page(s) of this test, which contains relevant data. If you do so, please remove it carefully so that remaining pages remain stapled. In order to prevent lost pages, please write your name on the top of each page, in addition to this cover page. 8. Before turning in your test, make sure that at a minimum pages 1-8 are attached. Page 2 18 points Page 3 13 points Page 4 19 points Page 5 18 points Page 6 22 points Page 7 10 points Page 8 10 points TOTAL 110 points Page 1 of 10

2 Name (Print) Section # or TA 1. (6 points) Using information tabulated below (on the last pages), calculate S r for the aqueous solution reaction of magnesium ions with chloride ions to form one mole of magnesium chloride solid at 25 C. a. 8.0 J K 1 mol 1 b. 8.0 J K 1 mol 1 c J K 1 mol 1 d J K 1 mol 1 2. (6 points) What is the normal boiling point of liquid Br 2 if the following reaction occurs spontaneously at 1 atm? Given H vap = 31 kj mol -1 and S vap = 93 J K -1 mol -1 a. 0.3 K b. 31 K c. 313 K d. 333 K Br 2 (l) Br 2 (g) 3. (6 point) Calculate G at 25 C for the reaction, C 2 H 5 OH (l) + 3 O 2 (g) 2 CO 2 (g) + 3 H 2 O (g) a kj b kj c kj d kj Page 2 of 10

3 Name (Print) Section # or TA 4. (7 points) Using data tabulated below (last pages), calculate the equilibrium constant at 25 C for the reaction, C 2 H 4 (g) + H 2 (g) C 2 H 6 (g) a. 2.0 x b. 41 c. 101 d. 5.0 x (6 points) Identify the correctly balanced reduction half reaction for the reaction, PbO 2 (s) + SO 2 4 (aq) + 4 H + (aq) + 2 Hg(l) + 2 Cl (aq) Hg 2 Cl 2 (s) + PbSO 4 (s) + 2 H 2 O(l) a. PbO 2 + SO H e PbSO H 2 O b. 2 Hg + 2 Cl Hg 2 Cl e c. PbSO H 2 O PbO 2 + SO H+ + 2 e d. Hg 2 Cl e 2 Hg + 2 Cl Page 3 of 10

4 Name (Print) Section # or TA 6. (7 points) When the reaction below is balanced in base with smallest integer coefficients, OH 's must be added to the side, and H 2 O's must be added to the side. a. 4, left, 2, right b. 4, left, 0,. c. 4, right, 2, left d. 4, right, 0,. N 2 H 4 (aq) + CO 3 2 (aq) N 2 (g) + CO (g) 7. (6 points) In balancing the Redox reaction in question 6, how many electrons are transferred. a. 1 b. 2 c. 4 d (6 points) How long will it take to plate 5.43 g of nickel onto an electrode from a solution of NiCl 2 at a current of amperes? [M Ni = g mol 1.] a s b. 723 s c s d s Page 4 of 10

5 Name (Print) Section # or TA 9. (6 points) From the E values tabulated below (last pages), an element or ion which will oxidize tin but will not oxidize silver is. Hint mark all of the species directly on the E table on page 9. a. Al b. Zn 2+ c. Fe 2+ d. Hg e. Cu (6 points) Compute the standard Gibbs energy for the following electrochemical cell at 25 C. The cell voltage for this reaction is volts at 25 C. a kj mol -1 b kj mol -1 c kj mol -1 d kj mol -1 Cd (s) Cd 2+ (aq) Zn 2+ (aq) Zn (s) 11. (6 points) An electrochemical cell has two compartments. In one, a platinum electrode dips into a solution containing iron (II) and iron (III), both at 1.00 M concentration. In the other compartment, a copper electrode is immersed in a 1.00 M solution of copper (II) nitrate. The two electrodes are connected by a copper wire and the two solutions are connected with a salt bridge. When this cell operates as a galvanic cell, what is the reduction half reaction? [See below, last pages, for E values.] a. Fe 2+ (aq) Fe 3+ (aq) + e b. Fe 3+ (aq) + e Fe 2+ (aq) c. Cu(s) Cu 2+ (aq) + 2 e d. Cu 2+ (aq) + 2 e Cu(s) Page 5 of 10

6 Name (Print) Section # or TA 12. (7 points) Using data provided on the last pages, compute the cell voltage for the following electrochemical cell at 25 C. a volts b volts c volts d volts Pt (s) Fe 2+ (aq), Fe 3+ (aq) MnO 4-1 (aq), H + (aq), Mn 2+ (aq) Pt (s) 13. (7 points) Which of the following is the rate law for a reaction that is first order in oxygen? a. rate = k [NO 2 ] b. rate = k [NO 2 ] [O 2 ] c. rate = k [NO 2 ] 2 [O 2 ] -1 d. rate = k [NO 2 ] 2 [O 2 ] -1 [N 2 ] 14. (8 points) The initial rate for the oxidation of iron (II) by cerium (IV) is measured at several different initial concentrations of the two reactants. What is the rate expression for this reaction? Ce 4+ (aq) + Fe 2+ (aq) Ce 3+ (aq) + Fe 3+ (aq) [Ce 4+ ] [Fe 2+ ] Initial Rate Run [mol L -1 ] [mol L -1 ] [mol L -1 s -1 ] x x x x x x x x x 10-7 a. rate = k [Ce +4 ] 0 [Fe 2+ ] 1 b. rate = k [Ce +4 ] 1 [Fe 2+ ] 1 c. rate = k [Ce +4 ] 2 [Fe 2+ ] 1 d. rate = k [Ce +4 ] 1 [Fe 2+ ] 2 Page 6 of 10

7 Name (Print) Section # or TA 15. (5 points) A plot of ln(k) versus 1/T has a slope of a. A b. E a c. E a /R d. ln A 16. (5 points) For a certain reaction, a plot of ln [A] versus t gives a straight line with a slope of 1.46 s 1 and a y intercept of The rate constant for this reaction is a s b s 1 c s 1 d s 1 Page 7 of 10

8 Name (Print) Section # or TA 17. EXTRA CREDIT (10 points) You may answer either A or B. You must show all of your work to receive any credit. Clearly indicate which question you wish graded. A. (10 points) Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: IO 3 (aq) + S 2 O 3 2 (aq) + H + (aq) I (aq) + S 4 O 7 2 (aq) + H 2 O(l) a. 1, 3, 3, 1, 3, 3 b. 6, 2, 6, 6, 1, 3 c. 2, 3, 3, 1, 1, 9 d. 2, 6, 6, 2, 3, 3 B. (10 points) Using data tabulated of the last page, estimate G r at T = 750 K for You can assume that H and S are roughly constant over the temperature range from 298K to 750K. a. 211 kj mol 1 b. 339 kj mol 1 c. 57 kj mol 1 d. 142 kj mol 1 Page 8 of 10

9 Name (Print) Section # or TA The following standard reduction potentials are valid for aqueous solutions at 25 C. Reduction Half-Reaction Standard Reduction Potential E (V) MnO 4 +8H + + 5e Mn H 2 O Au e Au Br e 2Br Hg e 2+ Hg Hg e Hg Ag + + e Ag Fe 3+ + e Fe I 2 (s) + 2e 2I Cu e Cu Sn e Sn Ni e Ni Cd e Cd Fe e Fe S + H 2 O + 2 e HS + OH S 2 O H 2 O + 4 e 2S + 6OH Zn e Zn Al e Al Mg e Mg Fundamental Constants and Conversions Atomic mass unit: u = 1.661x10-27 kg = (mass of 12 C/12) Avogadro's constant N 0 = x mol 1 Boiling point of H 2 O at P = 1 atm is C = K Calorie 1 cal = J (exactly) Electron charge e = x C Electron mass m e = x kg Faraday constant F = 96, C mol 1 Freezing point of H 2 O is 0.00 C = K Freezing point depression constant for water = 1.86 K kg mol -1 Ideal gas equation of state: PV = nrt MKS units of force and energy: 1 Newton = 1 kg m s -2 = unit of force = 1N 1 Joule = 1 kg m 2 s -2 = 1N m = unit of energy = 1J Planck's constant h = x J s Rydberg constant Ry = x J Speed of light in vacuum c = x 10 8 m s 1 (exactly) Standard Atmosphere 1 atm = x 10 5 Pa (exactly) Units of pressure: 1 atm = 760 mm Hg = x 10 5 Pa = x 10 5 kg m -1 s -2 Universal gas constant R = J mol 1 K 1 = L atm mol 1 K 1 Page 9 of 10

10 Name (Print) Section # or TA Species H f (25 C) (kj mol -1 ) S (25 C) (J K -1 mol -1 ) G f (25 C) (kj mol -1 ) C 2 H 2 (g) C 2 H 4 (g) C 2 H 6 (g) C 2 H 5 OH (l) CH 3 OH (l) Cl (aq) CO (g) CO 2 (g) Fe (s) H 2 (g) H 2 O (g) H 2 O (l) Mg 2+ (aq) MgCl 2 (s) NH 3 (g) NO (g) O 2 (g) O 3 (g) PbS (s) SO 2 (g) SO 3 (g) Page 10 of 10