CHM-201 General Chemistry and Laboratory I Unit #3 Take Home Test Due April 18, 2018

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3 CHM-201 General Chemistry and Laboratory I Unit #3 Take Home Test Due April 18, 2018 Directions: Complete this test and pass in the answer sheet 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. There is no need to fill in the version of the test. Absolutely no papers will be accepted after the due date. 1. What is the pressure of the sample of gas trapped in the open-tube mercury manometer shown below if atmospheric pressure is 736 mmhg and h = 9.2 cm? A) 92 mmhg B) 644 mmhg C) 736 mmhg D) 828 mmhg E) There is not enough information to determine the pressure. 2. A sample of pure oxygen gas has a pressure of 795 torr. What is the pressure of the oxygen in units of atmospheres? A) atm B) 1.05 atm C) atm D) atm E) 1.01 atm 3. A 45 ml sample of nitrogen gas is cooled from 135ºC to 15 C in a container that can contract or expand at constant pressure. What is the new volume of the nitrogen gas? A) 64 ml B) 5.0 ml C) 410 ml D) 32 ml E) 41 ml 4. A small bubble rises from the bottom of a lake, where the temperature and pressure are 4 C and 3.0 atm, to the water's surface, where the temperature is 25 C and the pressure is 0.95 atm. Calculate the final volume of the bubble if its initial volume was 2.1 ml. A) 0.72 ml B) 6.2 ml C) 7.1 ml D) 22.4 ml E) 41.4 ml 5. At what temperature will a sample of oxygen gas with a volume of L at 12 C and 822 mmhg occupy a volume of 345 ml at a pressure of 578 mm Hg? Assume the amount of the oxygen gas does not change. A) 129 C B) 355 C C) 402 C D) 629 C E) 903 C

4 6. Calculate the mass of 1.00 L of Br 2(g) at 59.0 C and 1.00 atm pressure. A) 3.45 g/l B) 5.83 g/l C) 22.4 g/l D) 27.2 g/l E) 769 g/l 7. Which of these gases will have the greatest density if they are all measured at the same temperature and pressure? A) Br 2 B) CClF 3 C) CCl 4 D) C 2H 2 E) CCl 2F 4 8. Determine the molar mass of Freon-11 gas if a sample weighing g occupies 100. cm 3 at 95 C, and 1,000. mmhg. A) 0.19 g/mol B) 35.3 g/mol C) 70.9 g/mol D) 137 g/mol E) 384 g/mol L of gas A at 1.0 atm and 1.0 L of gas B at 1.0 atm are combined in a 3.0 L flask. The flask is sealed and over time they react completely to give gas C according to the following chemical equation: 2A(g) + B(g) C(g) Assuming the temperature stays constant, what will be the pressure after the reaction goes to completion? A) 0.33 atm B) 0.50 atm C) 0.67 atm D) 0.75 atm E) 1.0 atm 10. What mass of KClO 3 must be decomposed to produce 126 L of oxygen gas at 133 C and atm? 2KClO 3(s) 2KCl(s) + 3O 2(g) A) 24.6 g B) 70.8 g C) 272 g D) 408 g E) 612 g

5 11. What is the atmospheric pressure if the pressure of the gas trapped in the apparatus shown below mmhg? A) 45 mmhg B) 650 mmhg C) 765 mmhg D) 675 mmhg E) 760 mmhg 12. An exothermic reaction causes the system to A) increase in temperature B) release CO 2. C) expand. D) decrease in temperature. E) become acidic. 13. A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/ C. What is the specific heat of copper? A) J/g C B) 1.32 J/g C C) 2.60 J/g C D) 24.5 J/g C E) J/g C 14. Which of the following processes is exothermic, given the following: N 2(g) + 2 O 2(g) N 2O 4(l) ΔH = 9.67 kj/mol N 2(g) + 2 O 2(g) 2 NO 2(g) ΔH = kj/mol A) 2 N 2(g) + 4 O 2(g) 2 N 2O 4(l) B) ½ N 2(g) + O 2(g) ½ N 2O 4(l) C) N 2O 4(l) N 2(g) + 2 O 2(g) D) 2 N 2(g) + 4 O 2(g) 2 NO 2(g) + N 2O 4(l) E) 2 N 2(g) + 4 O 2(g) 4 NO 2(g) 15. The reaction that represents the standard enthalpy of formation for sucrose (C 12H 22O 11) is: A) C 12H 22O 11(s) + 12 O 2 12 CO 2(g) + 11 H 2O(g) B) 12 C(diamond) + 11 H 2(g) + 11 / 2 O 2(g) C 12H 22O 11(s) C) 12 C(graphite) + 11 H 2(g) + 11 / 2 O 2(g) C 12H 22O 11(s) D) 24 C(diamond) + 22 H 2(g) + 11 O 2(g) 2 C 12H 22O 11(s) E) C 12H 22O 11(s) 12 C(graphite) + 11 H 2(g) + 11 / 2 O 2(g)

6 16. When g of Na(s) reacts with excess F 2(g) to form NaF(s), 13.8 kj of heat is evolved at standard-state conditions. What is the standard enthalpy of formation (ΔH f) of NaF(s)? A) -570 kj/mol B) 24.8 kj/mol C) 7.8 kj/mol D) 24.8 kj/mol E) 570 kj/mol 17. Styrene, C 8H 8, is one of the substances used in the production of synthetic rubber. When styrene burns in oxygen to form carbon dioxide and liquid water under standard-state conditions at 25 C, kj are released per gram of styrene. Find the standard enthalpy of formation of styrene at 25 C. (Given: ΔH f[co 2(g)] = kj/mol, ΔH f[h 2O(l)] = kj/mol, ΔH f[h 2O(g)] = kj/mol) A) kj/mol B) kj/mol C) ~636.7 kj/mol D) ~4249 kj/mol E) ~8730 kj/mol 18. Given H 2 (g) + ½ O 2(g) H 2O(l), ΔH = 286 kj/mol, determine the standard enthalpy change for the reaction 2H 2O(l) 2H 2(g) + O 2(g). A) ΔH = 286 kj/mol B) ΔH = +286 kj/mol C) ΔH = 572 kj/mol D) ΔH = +572 kj/mol E) ΔH = 143 kj/mol 19. Calculate the standard enthalpy change for the reaction 2A + 2A 2 + 4AB + B 5A 2B Given: 2A + B A 2B ΔH = kj 2 A 2B 2AB + A 2 ΔH = 35.0 kj A) 95.0 kj/mol B) 60.0 kj/mol C) 15.0 kj/mol D) 10.0 kj/mol E) 45.0 kj/mol 20. Calculate the enthalpy of reaction for H 2(g) + C 2H 4(g) C 2H 6(g). [ΔH f(c 2H 4(g)) = 52.3 kj/mol; ΔH f(c 2H 6(g)) = 84.7 kj/mol] A) 117 kj/mol B) 127 kj/mol C) 137 kj/mol D) 147 kj/mol E) None of the above

7 21. Find ΔH rxn for the reaction C 6H 12O 6(s) + 6 O 2 6 CO 2(g) + 6 H 2O(g). [ΔH f (C 6H 12O 6(s)) = kj/mol; ΔH f (H 2O(l)) = kj/mol]; ΔH f (CO 2(s)) = kj/mol] A) kj B) kj C) kj D) kj E) None of the above 22. Select True or False: ΔH = q when the thermal properties of a chemical reaction are carried out at constant pressure. A) True B) False