Please pass in only this completed answer sheet on the day of the test. LATE SUBMISSIONS WILL NOT BE ACCEPTED

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1 CHM-201 General Chemistry and Laboratory I Unit #3 Take Home Test Due April 8, 2019 Please pass in only this completed answer sheet on the day of the test. LATE SUBMISSIONS WILL NOT BE ACCEPTED

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3 CHM-201 General Chemistry and Laboratory I Unit #3 Take Home Test Due Monday, April 8, 2019 Directions: Complete this test and pass in the answer sheet portion on or before the due date. Please pass in ONLY the answer sheet. On the answer sheet, be sure to enter your student ID and fill in the appropriate bubbles. Record your answers unambiguously ambiguous answers are wrong. Do not cross out answers either erase/cover them completely or print a new answer sheet. Absolutely no papers will be accepted after the due date. 1. Work requires a. a use of potential energy. d. a change in temperature. b. a release of kinetic energy. e. the application of a force. c. that a force moves an object. 2. A diver jumps off a diving board. At which point in the diagram below will the diver possess the greatest kinetic energy? a. A d. D b. B e. E c. C 3. According to Coulomb s law, which ionic compound A D has the smallest electrostatic potential energy (i.e., closest to zero)? The size of the anion increases in the order F Cl Br I. a. NaF b. NaCl c. NaBr d. NaI e. All have the same potential energy because the anions all have 1 charges. 4. Which of the following is an endothermic process for the system? In each case, the system is underlined. a. a block of cheese being cooled in a refrigerator b. a hot pack being used to warm a sore muscle c. a heat pump being used to warm a house d. a candle burning at a dinner table e. ice cubes freezing in the refrigerator 5. Internal energy is defined as a. the total kinetic energy of all the system components. b. the total potential energy of all the system components. c. the total of the potential and kinetic energies of all the system components. d. the total potential energy minus the total kinetic energy of all the system components. e. the total kinetic energy minus the total potential energy of all the system components. 6. What is the change in internal energy ( E) of a system when it loses 10 kj of energy and 5,000 J of work is done on the system? a. +15 kj d. +5,010 J b. 10 kj e. +4,990 J c. 5 kj

4 7. The best definition of the enthalpy change is a. the energy that is transferred into or out of a system because of a temperature difference when the pressure is constant and only PV work is done. b. the change in internal energy of a system when the pressure is constant. c. the change in internal energy of a system when the volume is constant. d. the energy that is transferred into or out of a system when the pressure is constant and no work is done. e. the change in internal energy of a system when the pressure is constant and no work is done. 8. A cooling curve for some substance is shown below. Which of the line segments (I V) represents the liquid-to-solid transition? a. I d. IV b. II e. V c. III 9. A 15 g piece of iron (C P = J/(mol C)) is heated to a temperature of 95 C and placed into a bucket containing 4.5 gal of water (C P = J/(mol C)) initially at 25 C. Eventually, a. the water will be warmer than the iron. b. the iron will be warmer than the water. c. the iron will be colder than the water. d. the iron and the water will be at the same temperature. e. the temperature will be the average of 95 C and 25 C.

5 10. Using the data shown below for water, determine in the following heating curve what region the water will be in when 50 g of ice at 25 is provided with 35 kj of energy. Boiling point 373 K Melting point 273 K Enthalpy of vaporization 2,260 J/g Enthalpy of fusion 334 J/g Specific heat capacity (solid) 2.11 J/(g K) Specific heat capacity (liquid) 4.18 J/(g K) Specific heat capacity (gas) 2.08 J/(g K) a. I d. IV b. II e. V c. III 11. When 1.14 g of octane (molar mass = 114 g/mol) reacts with excess oxygen in a constant volume calorimeter, the temperature of the calorimeter increases by 10.0 C. The heat capacity of the calorimeter is 6.97 kj/ C. Determine the energy flow, q (reaction). a kj d. 6,970 kj b. +6,970 kj e kj c kj 12. Use the following information to determine the enthalpy for the reaction shown below. CH4(g) + H2O(g) CO(g) + 3H2(g) H =? 2C(s) + 2H 2O(g) CH 4(g) + CO 2(g) C(s) + H 2O(g) CO(g) + H 2(g) CO(g) + H 2O(g) CO 2(g) + H 2(g) H = 15.3 kj H = kj H = 41.2 kj a kj d kj b kj e kj c kj 13. For which reaction below does the enthalpy change under standard conditions correspond to a standard enthalpy of formation? a. CO(g) H 2O(g) CO 2(g) H 2(g) b. SO 2(g) ½ O 2(g) SO 3(g) c. N 2(g) 2O 2(g) 2NO 2(g) d. ½ H 2(g) ½ N 2(g) 3 / 2 O 2(g) HNO 3(g) e. CH 4(g) 2O 2(g) CO 2(g) 2H 2O(g)

6 14. Coal is converted into cleaner, more transportable fuels by burning it with oxygen to produce carbon monoxide. The carbon monoxide then is reacted with hydrogen using a catalyst to produce methane and water. Is the reaction between CO and H 2 exothermic or endothermic, and what is the change in enthalpy for it? The enthalpies of formation of the reactants and products are given below. Molecule in kj/mol CO 110 H 2 0 CH 4 75 H 2O 242 a. exothermic, +317 kj/mol d. endothermic, +427 kj/mol b. endothermic, +207 kj/mol e. exothermic, 207 kj/mol c. exothermic, 427 kj/mol 15. A 25.0 L balloon is filled with 2.75 mol of helium. If the helium leaks out at the rate of mol/hr, what is the volume of the balloon after 12.0 hr? Assume the pressure and temperature don t change. a L d L b L e L c L 16. Four containers, each with the same volume and at the same temperature, are shown in the following diagrams. Which container is at the highest pressure? (Each dot represents one mole of the gas.) a. c. b. d. 17. The pressure gauge on a cylinder used to fill balloons with He shows a pressure of atm psi at a temperature of 25 C. Assuming the cylinder has a volume of 10 L, how many grams of He does the cylinder contain? a. 520 g d g b. 142 g e g c x 10-4 g 18. Considering that PV = nrt, which one of these samples contains the smallest number of particles? STP = 0 C and 1 atm. a. 2.0 L of H 2 at STP d. 2.0 L of N 2 at 0 C and 900 torr b. 2.0 L of N 2 at STP e. 2.0 L of He at STP c. 2.0 L of H 2 at 25 C and 760 torr 19. Which of the following reactions will result in a reduced total pressure? a. CH 4(g) 2O 2(g) CO 2(g) 2H 2O(g) b. 2N 2O(g) 2N 2(g) O 2(g) c. 2HI(g) H 2(g) I 2(g) d. 2H 2(g) O 2(g) 2H 2O(l )

7 20. What is the pressure of 2.95g of NO gas in a 2.2L container at 25 C? a atm d atm b atm e atm c atm 21. In which of the following containers is the mole fraction of argon greatest? The white circles represent helium atoms; the dark circles represent argon atoms. a. c. b. d. 22. Dry air consists of 78.1% nitrogen (28 g/mol), 20.9% oxygen (32 g/mol), 0.9% argon (40 g/mol), 0.03% carbon dioxide (44 g/mol), and 0.07% other gases by volume. What is the partial pressure of oxygen in air when the total pressure is 760 torr? a. 594 torr d. 59 torr b. 159 torr e. 236 torr c. 94 torr