THE ANSWER KEY TO THIS EXAM WILL BE POSTED ON THE CHEM 177-D BLACKBOARD LEARN SITE

Transcription

1 CHEM 177-D Exam II October 14, 2016 Name : Recit. Instr. : Recit. Sect. : Recitation Instructors and Sections Recitation Instructor Section Time Caryn Zaruba 43 R 8:00 Dean Jose 44, 47 R 9:00, 10:00 Saad Tarik 45, 46 R 9:00, 10:00 Marcelino Varona Ortiz 48, 51 R 11:00, 12:00 Caroline Warner 49, 50 R 11:00, 12:00 Yanhua Huang 52, 54 R 1:00, 2:00 Luan M. Nguyen 53 R 2:00 Jared Ballew 55, 56 R 3:00, 4:00 Nicole Stephens 57, 58 R 4:00, 5:00 Grading: This exam consists of 20 multiple-choice questions. Each question is worth 10 points. Total Points: 200 THE ANSWER KEY TO THIS EXAM WILL BE POSTED ON THE CHEM 177-D BLACKBOARD LEARN SITE

2 Using #2 pencil, complete the left part of your bubble sheet with your name, university ID and recitation number as shown in the example. First Name Last Name University ID number (middle 9 digits only) Recitation Section number (See next page)

3 1 A 1 Pe riodic Table of t he Ele me nt s 8 A H A 2 3 A A A A A He Li Na K Rb Cs Fr (2 2 3 ) 4 Be Mg Ca Sr Ba Ra B Sc Y La Ac B Ti Zr Hf Rf (2 6 1 ) 5 B V Nb Ta Db (2 6 2 ) 6 B Cr Mo W Sg (2 6 3 ) 7 B Mn Tc (9 8 ) 7 5 Re Bh (2 6 2 ) Fe Ru Os Hs (2 6 5 ) 8 B Co Rh Ir Mt (2 6 6 ) Ni Pd Pt Ds (2 8 1 ) 1 B Cu Ag Au B Zn Cd Hg B Al Ga In Tl C Si Ge Sn Pb N P As Sb Bi O S Se Te Po (2 0 9 ) 9 F Cl Br I At (2 1 0 ) 1 0 Ne Ar Kr Xe Rn (2 2 2 ) Lant hanides Act inides 5 8 Ce Th Pr Pa Nd U Pm (1 4 5 ) 9 3 Np (2 3 7 ) 6 2 Sm Pu (2 4 4 ) 6 3 Eu Am (2 4 3 ) 6 4 Gd Cm (2 4 7 ) 6 5 Tb Bk (2 4 7 ) 6 6 Dy Cf (2 5 1 ) 6 7 Ho Es (2 5 2 ) 6 8 Er Fm (2 5 7 ) 6 9 Tm Md (2 5 8 ) 7 0 Yb No (2 5 9 ) 7 1 Lu Lr (2 6 0 ) N a = amu = g 1 m = 10 dm = 100 cm = 1000 mm h= J s c = m/s 0 ºC = K E = hv

4 1. Water is acting as a Brønsted-Lowry base in which of the following reactions: (A) H 2 O(l) + HCOOH(aq) H 3 O + (aq) + HCOO - (aq) (B) H 2 O(l) + NaH(s) Na + (aq) + OH - (aq) + H 2 (g) (C) H 2 O(l) + NH 3 (aq) NH 4 OH(aq) (D) 2H 2 O(l) + CaH 2 (s) Ca 2+ (aq) + 2OH - (aq) + 2H 2 (g) 2. Which of the following reactions is not a redox reaction? (A) AgNO 3 + K 2 SO 4 2KNO 3 + Ag 2 SO 4 (B) 2Fe + 3Cl 2 2FeCl 3 (C) 5CO + I 2 O 5 5CO 2 + I 2 (D) NiO 2 + 2H 2 O + Fe Ni(OH) 2 + Fe(OH) 2 3. What volume of 12.0 M HCl is required to prepare 40 ml of a M HCl solution? (A) ml (B) ml (C) ml (D) ml 4. The titration of a mL sample of an HCl solution of unknown concentration requires ml of a M NaOH solution to reach the equivalence point. What is the concentration of the unknown HCl solution in M? (A) M (B) M (C) M (D) M

5 5. H 2 and O 2 react to form H 2 O by the equation: 4H 2 (g) + O 2 (g)! 2 H 2 O(g). If a reaction vessel initially contained 1000 H 2 molecules and 200 O 2 molecules, which molecules would be present if the reaction proceeds completely towards product? H 2 molecules O 2 molecules H 2 O molecules (A) (B) (C) (D) What is the total concentration of ions in a 1.2 M K 3 PO 4 solution? (A) 1.2 M (B) 2.6 M (C) 3.8 M (D) 4.8 M 7. What volume (in ml) of M NaOH is required to titrate ml of M HBr to the equivalence point? (A) 24.5 ml (B) 22.5 ml (C) 20.5 ml (D) 18.5 ml 8. Suppose Dr. Who travels through time in his British blue police box from 1980 and gives you a U.S. penny that is stuck in a block of ice. The penny had been frozen by an ice monster and temperature of the ice block is -20 ºC. He wants to thaw the penny to room temperature (25 ºC) and examines to see if it might help him to figure out what those ice monsters are up to. After consulting with a humanoid robot named Wikipedia on his spaceship, he finds that pre-1982 pennies are made of pure copper and the specific heat of copper is J/g ºC. How much heat is absorbed by the penny as it warms from the temperature of the ice block to room temperature if the mass of the penny is 3.10 g? (A) 51.7 J (B) 53.7 J (C) J (D) -53.7

6 9. The dissolution of calcium chloride is an exothermic process. When a sample of CaCl 2 dissolves in water, CaCl 2 (s) Ca 2+ (aq) + 2 Cl - (aq) (A) The value of ΔH is positive and the temperature of water will decrease. (B) The value of ΔH is positive and the temperature of water will increase. (C) The value of ΔH is negative and the temperature of water will decrease. (D) The value of ΔH is negative and the temperature of water will increase. 10. Calculate the heat in kj associated with the complete reaction of 155 g of NH 3 with oxygen according to the following reaction: 4NH 3 (g) + 5O 2 (g)! 4NO(g) + 6H 2 O(l) ΔH o = -906 kj (A) kj (B) kj (C) kj (D) kj Use the given information below to answer question 11 and 12: In biological cells that have a sufficient supply of O 2, glucose (C 6 H 12 O 6 ) is oxidized completely to CO 2 and H 2 O. Muscle cells may be deprived of O 2 during vigorous exercise and, in that case, one molecule of glucose is converted to two molecules of lactic acid, CH 3 CH(OH)COOH, by a process called glycolysis. C 6 H 12 O 6 (s) + 6 O 2 (g) 6 CO 2 (g) + 6 H 2 O (l) ΔHº = 2808 kj CH 3 CH(OH)COOH (s) + 3 O 2 (g) 3 CO 2 (g) + 3 H 2 O (l) ΔHº = 1344 kj 11. Calculate the standard enthalpy for the glycolysis reaction: C 6 H 12 O 6 (s) 2 CH 3 CH(OH)COOH (s) (A) +120 kj (B) 120 kj (C) kj (D) 4152 kj ΔHº =? kj

7 12. Is there a biological advantage of complete oxidation of glucose compared with glycolysis? Choose the best explanation. (A) Glycolysis is more useful because the standard enthalpy for glycolysis shows that there is more energy available to perform work. (B) Glycolysis is more useful because the standard enthalpy for the combustion of lactic acid shows that there is more energy available to perform work. (C) Full oxidation of glucose is metabolically more useful because the standard enthalpy shows that there is more energy available to perform work. (D) Full oxidation of glucose is metabolically less useful because the combined standard enthalpy of lactic acid combustion and glycolysis shows that there is more energy available to perform work. 13. If the final state of a process has a higher enthalpy than the starting state, then: (A) The change in enthalpy is positive, energy is transferred from the system, and the process is endothermic. (B) The change in enthalpy is positive, energy is transferred to the system, and the process is endothermic. (C) The change in enthalpy is negative, energy is transferred from the system, and the process is exothermic. (D) The change in enthalpy is negative, energy is transferred to the system, and the process is exothermic. 14. Which of the following is a closed system? (A) A fertilized hen s egg (B) A bacterial cell (C) A sealed container that is thermally, mechanically, and electrically insulated from its surroundings (D) A sealed container that is thermally and mechanically but not electrically insulated from its surroundings

8 15. A cylinder and piston assembly (defined as the system) is warmed by an external flame. The contents of the cylinder expand, doing work on the surroundings by pushing the piston outward against the external pressure. If the system absorbs 559 J of heat and does 488 J of work during the expansion, what is the value of ΔE? (A) -998 J (B) 1047 J (C) 74 J (D) A nitrogen gas laser pulse with a wavelength of 337 nm contains 3.83 mj of energy? How many photons does it contain? (A) (B) (C) (D) Determine the wavelength of light emitted when an electron in a hydrogen atom makes a transition from an orbital in n = 6 to an orbital in n = 5. (A) m (B) m (C) m (D) m 18. Which is NOT an allowed set of quantum numbers? n l m l m s (A) /2 (B) /2 (C) /2 (D) /2

9 19. What is the ground state electron configuration of the V +2 ion? (A) [Ar]3d 3 (B) [Ar]4s 1 3d 4 (C) [Ar]4s 2 3d 3 (D) [Ar]4s 2 3d To what element does this orbital diagram correspond? (A) P (B) Mn (C) Ar (D) Br E 21. What is the ground state electron configuration of Ge? (A) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 1 (B) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 2 (C) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 3 (D) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4