Name Section Number TA. 1. You may use crib sheets which you prepared in your own handwriting. This may be up to

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1 1. You may use crib sheets which you prepared in your own handwriting. This may be up to five 8-1/2 by 11 inch sheets of paper with handwriting only on one side. This corresponds to one page each for Chapters 1-6, 7-10, and Multiple Choice, no partial credit. 3. You may remove the last two pages 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 of page, in addition to this cover page. 4. Before turning in your test, make sure that you have the correct number of pages, totaling 200 points. 5. Show your Buzz Card when you turn in your completed exam. 6. 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 Page 2 20 points Page 3 15 points Page 4 15 points Pages points Part A Page 5 18 points Page 6 20 points Page 7 13 points Page 8 14 points Pages points Part B Page 9 20 points Page points Page points Pages points Part C Page points Page points Part D Total 200 points Total 200 points Page 1 of 14

2 1. (5 points) When an aqueous solution of iron(ii) chloride is combined with an aqueous solution of ammonium sulfite, the predicted result would be the precipitation of a. FeSO 3 b. FeS c. Fe 2 S 3 d. FeSO 4 2. (5 points) What is the oxidation number for the Sulfur atom in Fe 2 (SO 4 ) 3? a. +2 b. +6 c. +3 d (5 points) Which of the following equations represents an oxidation-reduction reaction? a. Na 2 SO 4 (aq) + BaCl 2 (aq) BaSO 4 (s) + 2 NaCl (aq) b. MgCO 3 (s) MgO (s) + CO 2 (g) c. 2 ZnS (s) + 3 O 2 (g) 2 ZnO (s) + 2SO 2 (g) d. all of these 4. (5 points) At 25.0 C and 1.00 atm a gas sample occupies a volume of 1.50 L. At C and 1.00 atm, the same gas sample will occupy a L b L c L d L Page 2 of 14

3 5. (5 points) A gas is in a container with movable walls under a pressure of 5.50 atm. The volume of the container is increased by a factor of 3.25 times the initial volume by moving its walls. The absolute temperature is simultaneously doubled. Calculate the pressure of the gas after these changes. a atm b atm c atm d atm 6. (5 points) Joseph Priestley obtained oxygen from the thermal decomposition of mercury (II) oxide, which yields elemental mercury [Hg (l)] in addition to oxygen. If g of the oxide is completely decomposed, what volume of oxygen will be produced at C and atm? a L b L c L d L 7. (5 points) Octane (C 8 H 18 ), a major component of gasoline, burns completely in an oxygen atmosphere to produce carbon dioxide and water as the only products. If this reaction, i.e., w C 8 H 18 + x O 2 y H 2 O + z CO 2, is described with a balanced chemical equation using the smallest possible integer coefficients, what is z, the stoichiometric coefficient for CO 2? a. 16 b. 18 c. 25 d. 8 Page 3 of 14

4 8. (5 points) What is the percentage by mass of hydrogen (H) in a compound with empirical formula C 2 NH 7? a. 10 b. 16 c. 35 d (5 points.) Which of the following pairs of elements is most likely to form an ionic bond? a. Cs, Cl b. P, H c. N, O d. C, Cl 10. (5 points) From the Lewis structure, use VSEPR theory to determine the steric number of the central atom of ozone (O 3 ) and the O O O bond angle. a. Steric number 3, less than 120 degrees b. Steric number 2, 180 degrees c. Steric number 3, greater than 120 degrees d. Steric number 4, less than degrees Page 4 of 14

5 11. (5 points) Consider the equilibrium reaction below. PCl 3 (g) + Cl 2 (g) PCl 5 (g) The equilibrium expression for the reaction is K = 12. (8 points) Consider the following equilibrium reaction At 300 C, atm of Cl 2 (g) is initially mixed with 1.40 atm of NO (g). At equilibrium, atm of NOCl (g) is present. Calculate K for the reaction. a b c d (5 points) If the equation in question 12 were rewritten as follows, the equilibrium constant would change from the original value of K to a. K b. K 1/2 c. 1/K d. K 2 Page 5 of 14

6 14. (5 points) The conjugate base of HPO 2 4 is 2 a. HPO 4 3 b. PO 4 c. H 2 PO 4 d. H 3 PO (6 points) In a sample of orange juice at 25 C, [H 3 O + ] = 1.78 x 10 3 M. The ph of the juice is therefore a b c d (9 points) Pyridine (C 5 H 5 N) is a weak base and forms the pyridinium ion when placed in water. At 25 C, a M aqueous solution of pyridine has a ph of 9.1. The pk b of pyridine is a. 8.8 b. 10 c. 5.2 d. 4 C 5 H 5 N (l) + H 2 O (l) C 5 H 5 NH + (aq) + OH (aq) Page 6 of 14

7 17. (6 points) Consider the following solubility product data for various carbonates at 25 C: K sp Ag 2 CO x BaCO x 10 9 CaCO x 10 9 SrCO x 10 9 The carbonate that is most soluble in water at 25 C is a. Ag 2 CO 3 b. CaCO 3 c. BaCO 3 d. SrCO (7 points) Consider the solubility data in problem 17. The solubility of Ag 2 CO 3 (s) in an aqueous solution of 0.15 M Na 2 CO 3 at 25 C is a. 3.2 x 10 6 M b. 4.1 x M c. 6.4 x 10 6 M d. 1.2 x 10 4 M Page 7 of 14

8 19. (7 points) A 1.25 L sample of a gas is heated and expands against a constant pressure of 0.86 atm to a final volume of 3.75 L. Compute the work done on the gas during the expansion. Note that work flows from the system to the surroundings in this problem a. 218 J b J c J d. 218 J 20. (7 points) For a certain liquid hydrocarbon H vap = kj mol 1. The density of the hydrocarbon is 1.13 g/ml. Calculate the change in enthalpy for the vaporization of mol of the hydrocarbon. a kj b kj c kj d kj Page 8 of 14

9 21. (5 points) Under what conditions will the reaction, 2 N 2 (g) + O 2 (g) 2 N 2 O (g), be spontaneous? At 25 C, G f and H f for dinitrogen oxide are kj mol 1 and 82.0 kj mol 1, respectively. a. under all conditions b. at high temperature c. under no conditions d. at low temperature 22. (7 points) 2.50 moles of liquid benzene (C 6 H 6 ) is converted to vapor at a pressure of 1.00 atm. and a temperature of 80.1 C, its normal boiling point. H vap for benzene at this temperature is 30.8 kj mol 1. Calculate S for the benzene in this process. a. 218 J K 1 b. 218 J K 1 c. 174 J K 1 d. 87 J K (8 points) Calculate the equilibrium constant for the dehydration of gaseous ethane (C 2 H 6 ) to acetylene (C 2 H 2 ) at 25 C. You may use the data provided on the last page. a b. 3.8 x c d. 2.6 x C 2 H 6 (g) C 2 H 2 (g) + 2H 2 (g) Page 9 of 14

10 24. (5 points) For the half-reaction, Br 2 (l) + 2 e 2 Br (aq), the standard reduction potential is volts. What is the standard reduction potential for the following half-reaction? a. E = V b. E = V c. E = V d. E = V 2 Br 2 (l) + 4 e 4 Br (aq) 25. (9 points) When the following redox reaction is correctly balanced in a basic solution, how many electrons are transferred? a. 4 b. 2 c. 1 d. 6 Sn (OH) 6 2 (aq) + Si (s) + OH 1 (aq) HSnO 2 1 (aq) + SiO 3 2 (aq) + H 2 O (l) 26. (7 points) What number of coulombs of electricity is required for the following reduction? 2.50 mol of MnO 2 (s) to MnO 4 1 (aq) a x 10 5 C b x 10 5 C c x 10 5 C d x 10 5 C Page 10 of 14

11 27. (6 points) From E values tabulated at the end of the test, which of the following species is the strongest reducing agent? a. Zn b. Ni 2+ c. Sn 2+ d. Mg (6 points) Identify the reducing agent in the reaction, PbO 2 (s) + SO 4 2 (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 b. SO 4 2 c. H + d. Hg 29. (6 points) The following data were obtained for the following reaction at a certain temperature. 2 X (g) 2 Y (g) + Z (g) [X] Rate (mol L -1 ) (mol L -1 s -1 ) x x x 10-5 Calculate the overall order of this reaction from the experimental data. a. 2 b. 1.5 c. 1 d (6 points) Calculate the rate constant from the reaction and experimental data given in question 29. a L mol -1 s -1 b L mol -1 s -1 c L mol -1 s -1 d L mol -1 s -1 Page 11 of 14

12 31. (5 points) An unknown element when placed flame emits light as excited state atoms undergo transitions from one energy level to another level that lies 3.6 x J lower in energy. What is the wavelength of the light emitted? a. 550 nm b. 493 nm c. 671 nm d. 750 nm 32. (5 points) The output of a laser is measured by its wattage, the number of joules of energy it radiates per second (1 watt = 1 J s -1 ). A laser operates at a wavelength of nm and a power of mw (or 8.5 x 10-3 watts). Calculate the number of photons produced per second by this laser. (Hint: first calculate the energy of one photon). a x10 18 b x c x 10 6 d x (5 points) Identify the atom or ion corresponding to the following description. An ion with charge -2 and ground-state electron configuration [He] 2s 2 2p 4. a. Ne b. C 2 c. O d. O (5 points) Give the ground-state electron configuration for the Co atom. a. [Ar]3d 2 4s 5 b. [Ar]3d 5 4s 2 c. [Ar]3d 5 4s 1 d. [Ar]3d 7 4s 2 Page 12 of 14

13 ************************************************************************ The following standard reduction potentials are valid for aqueous solutions at 25 C. Reduction Half-Reaction Standard Reduction Potential E (V) Au e Au Br e 2Βr NO H e HNO2 + H2O Hg e 2+ Hg Hg e Hg Ag + + e Ag Hg e 2 Hg Fe 3+ + e Fe I 2 (s) + 2e 2I Cu e Cu Sn e Sn Ni e Ni Fe e Fe S + H 2 O + 2 e HS + OH S 2 O H 2 O + 4 e 2 S + 6 OH 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 per mol e Freezing point of H 2 O is 0.00 C = K 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 13 of 14

14 Species Hf (25 C) (kj mol -1 ) S (25 C) (J K -1 mol -1 ) G f (25 C) (kj mol -1 ) Al (s) C (s) C 2 H 2 (g) C 2 H 5 OH(l) C 2 H 6 (g) CH 3 OH (l) 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) Last page Page 14 of 14