UNIVERSITY OF VICTORIA CHEMISTRY 102 Midterm Test 2 March 13, pm (60 minutes) DISPLAY YOUR STUDENT ID CARD (ONECard) ON TOP OF YOUR DESK NOW

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Version A UNIVERSITY OF VICTORIA CHEMISTRY 102 Midterm Test 2 March 13, 2015 5-6 pm (60 minutes) Version A DISPLAY YOUR STUDENT ID CARD (ONECard) ON TOP OF YOUR DESK NOW Answer all multiple choice

1 Version A UNIVERSITY OF VICTORIA CHEMISTRY 102 Midterm Test 2 March 13, pm (60 minutes) Version A DISPLAY YOUR STUDENT ID CARD (ONECard) ON TOP OF YOUR DESK NOW Answer all multiple choice questions on the new-format bubble sheet provided. Use a pen (or soft pencil). Complete the identification portion of the bubble sheet according to the example shown, using your own name and student ID number. Indicate your Test Version (A or B) in the line labeled Form. Hand in only the bubble sheet at the end of the test period (60 minutes). A DATA sheet is included, unstapled, inside the cover page of this test. This test has 8 pages (not including the DATA sheet). Count the pages before you begin. The basic Sharp EL510 calculator and the Sharp EL-510 RNB are the only ones approved for use in Chemistry 102. DO NOT BEGIN UNTIL TOLD TO DO SO BY THE INVIGILATOR

2 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 2 of 8 This test consists entirely of multiple choice questions and is worth 25 marks. The answers for the 25 questions must be coded on the optical sense form (bubble sheet) using a PEN or SOFT PENCIL. Select the BEST response for each question below. 1) 0.23 g of ethanol (C 2 H 5 OH) was burned in a bomb calorimeter (constant volume) leading to a temperature change from 22.50ºC to 23.81ºC. If the heat capacity of the calorimeter is 5.2 kj/k, what would be the amount of heat generated by the combustion of exactly one mole of ethanol? A) kj/mol B) kj/mol C) -676 kj/mol D) -322 kj/mol E) kj/mol 2) The amount of heat calculated above in Question #1 corresponds to: A) The S for the combustion of 1 mole of ethanol. B) The H for the combustion of 1 mole of ethanol. C) The E for the combustion of 1 mole of ethanol. D) The expansion work w during the combustion of 1 mole of ethanol. E) The V for the combustion of 1 mole of ethanol. 3) Considering the following thermochemical equations: 2 CO(g) 2C(s) + O 2 (g) H = +221 kj 4CH 3 OH(g) 4C(s) + 2O 2 (g) + 8H 2 (g) H = +805 kj The H for the reaction: CO(g) + 2 H 2 (g) CH 3 OH(g) is: A) kj B) kj C) -110 kj D) kj E) +110 kj 4) The Hº for the reaction 2H 2 O 2 (g) 2H 2 O(g) + O 2 (g) is: (Use Data Sheet.) A) -105 kj B) -481 kj C) +105 kj D) kj E) -211 kj

3 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 3 of 8 5) Considering a drop of water on a surface represented by the figure below a student reached the following three conclusions: I. The water droplet is a sphere due to the surface tension of the water. II. The adhesive forces between the water and the surface are very Drop of water weak. III. The cohesive forces between the molecules of water are strong. What is your opinion about those conclusions? A) Only I is correct B) Only II is correct C) Only I and III are correct D) All of them are correct E) Only II and III are correct 6) Which property DECREASES as the strength of the London dispersion forces increases? A) Boiling point B) Melting point C) Enthalpy of vapourization D) Vapour pressure E) None of these properties decrease. 7) Consider the heating curve below: And the following statements: I the segment A-B corresponds to the heating of a solid. II the segment D-E corresponds to the vaporization of a liquid. III the segment E F corresponds to the heating of a liquid. IV the segment B C corresponds to a phase change. One can conclude that: A) Only I is false. B) Only III is false. C) Only I and IV are false. D) All of them are false. E) Only II, III and IV are false.

Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 4 of 8 8) Which dashed line in the phase diagram below best represents the process C-D-E-F in the heating curve of the previous question?

4 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 4 of 8 8) Which dashed line in the phase diagram below best represents the process C-D-E-F in the heating curve of the previous question? E y A D B C A B C D E 9) Which of the following statements about points z and y in the phase diagram of the previous questions is incorrect? A) solid, liquid and gas phases are in equilibrium at point z. B) z is known as the triple point. C) y is known as the critical point. D) A liquid-gas interface cannot be observed for temperatures & pressures higher than at point y. E) A supercritical fluid is obtained when temperature and pressure are higher than at point z. 10) Consider the P-V curves below for three different liquids: Which of the following statements is false? A) The normal boiling point of chloroform is about 60 ºC. B) Water is the least volatile of the three liquids. C) The boiling point of water on top of the Mount Everest is less than 100 ºC. D) The normal boiling point of ethanol is about 70 ºC. E) The vapour pressure of chloroform will be the highest at a given temperature.

5 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 5 of 8 11) A certain gas expands from 40.0 L to 60.0 L at 55 C. From the point of view of the system, what is the work (in Joules) involved in this change if the gas is expanding against a constant pressure of 1.25 atm? A) B) C) D) E) ) Using enthalpies of formation from the data sheet, the molar enthalpy of vaporization of benzene C 6 H 6 at 25 C is calculated to be (in kj mol -1 ): A) B) C) D) E) ) The standard enthalpy of formation of NiSO4(s) at 25 C is kj/mole. The chemical equation to which this value applies is: A) ½ Ni(s) + ½ S(s) + ½ O2(g) ½ NiSO4(s) B) Ni(s) + S(s) + 4 O(g) NiSO4(s) C) ½ Ni(s) + ½ S(s) + O2(g) ½ NiSO4(s) D) Ni(s) + S(s) + 2 O2(g) NiSO4(s) E) NiSO4(s) Ni(s) + S(s) + 4 O(g). 14) At 25 ºC, the Kp for the reaction N 2 O 4 (g) 2NO 2 (g) is What is the value of K c? A) 92.4R B) 0.001R C) 0.001R -1 D) 92.4R -1 E) 0.31R

6 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 6 of 8 15) Indicate the correct (true) statement regarding concentrations at equilibrium: A) The concentrations of reactants and products are equal at equilibrium. B) The concentrations of reactants and products have to be different at equilibrium. C) The concentrations of reactants and products increase at equilibrium. D) The concentrations of reactants and products do not change at equilibrium. E) The concentration of products is always higher than the concentration of reactants at equilibrium. 16) Which of the following pairs of chemical equation & equilibrium constant expression is/are CORRECT? i. 4 Bi(s) + 3 O 2 (g) 2 Bi 2 O 3 (s), K = [O 2 ] 3 ii. Ba(s) + 2 H + (aq) Ba 2+ (aq) + H 2 (g), K = iii. Ti(s) + 2 Cl 2 (g) TiCl 4 (l), K = 1 2 [ Cl2 ] 2 [ Ba ][ H 2 ] [ H ] iv. 4 NH 3 (g) + 5 O 2 (g) 4 NO(g) + 6 H 2 O(l), K = 4 P NO 4 5 PNH 3 PO 2 A) i only B) ii only C) i, ii, and iv D) iv only E) iii and iv 17) Consider the equilibrium reaction: 2NO 2 (g) N 2 O 4 (g) A container initially holds a mixture of 2.0 atm of N 2 O 4 and 1.0 atm of NO 2. The system is allowed to equilibrate and it is noticed that the pressure of NO 2 has increased by 0.3 atm. What is the Kp for this equilibrium? A) 0.91 B) 1.42 C) 0.83 D) 1.09 E) ) Consider the equilibrium 4 NH 3 (g) + 5 O 2 (g) 4 NO(g) + 6 H 2 O(g). Which one of the following statements correctly describes what happens when the described change is made in the reaction vessel. Interpret the arrow symbol to mean has the result that A) NO is added to the reaction vessel the amount of H 2 O increases B) O 2 is removed from the reaction vessel the amount of NH 3 increases C) NH 3 is added to the reaction vessel the value of K P decreases D) The total pressure is increased by compression the amount of NO increases E) The total pressure is increased by compression no change in concentrations is observed

7 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 7 of 8 19) Consider the following equilibrium: 2 HI(g) H 2 (g) + I 2 (g) If the equilibrium constant for this reaction at a certain temperature is K c = 0.04, what is the equilibrium constant K c for the following reaction at the same temperature: ½H 2 (g) + ½I 2 (g) HI(g) A) 5.0 B) 5.0 C) 25 D) E) ) One of the demonstrations in this course was about the effect of temperature in chemical equilibrium. NO 2 (a brown gas) was kept in a flask in equilibrium with N 2 O 4 (a colorless gas). When the flask was immersed in liquid nitrogen, the mixture inside became colorless. On the other hand, when the flask was immersed in hot water, the mixture inside was brown. What can you say about the equilibrium: N 2 O 4 (g) 2NO 2 (g) from these observations? A) The reaction is endothermic as written. B) The reaction is exothermic as written. C) K c and K p are the same. D) The partial pressure of the gases inside the tube does not depend on the temperature. E) The temperature increase shifts the equilibrium towards fewer moles of gases. 21) Rank the standard molar entropy of the following from lowest to highest: (i) SO 2 (l) (ii) SO 2 (g) (iii) SO 3 (l) (iv) SO 3 (g) A) iv < i < iii < ii B) i < iii < iv < ii C) iii < i < iv < ii D) ii < iv < iii < i E) i < iii < ii < iv 22) In terms of entropy, what happens when hydrogen and oxygen spontaneously react in gas phase to form water, according to 2H 2 (g) + O 2 (g) 2H 2 O(g)? A) The entropy of the system increases. B) The entropy of the universe increases. C) The entropy of the system remains the same. D) The entropy of the surroundings decreases. E) The entropy of the surroundings does not change.

8 Chemistry 102, Mid-Term Test 2 Version A March 13, 2015 Page 8 of 8 23) Indicate the false statement about the laws of thermodynamics: A) The third law defines an absolute zero for entropy. B) The first law indicates that the energy in the whole universe is conserved. C) The second law defines a condition for a spontaneous process to occur. D) The third law indicates that the entropy of a perfect crystal is always zero. E) The second law indicates that changes in entropy in both the system and the surroundings must be considered to determine if a process is spontaneous or not. 24) A spontaneous process: A) will happen quickly. B) releases large amounts of energy. C) produces the maximum amount of work. D) will continue on its own once begun. E) is reversible. 25) A reaction mixture consisting of mol H 2 and 1.60 mol I 2 was introduced into a 3.00 L flask and heated. At equilibrium 60% of the hydrogen gas had reacted. What is the equilibrium constant K C for the reaction H 2 (g) + I 2 (g) 2HI(g)? A) 2.21 B) 1.10 C) D) E) 1.06 END

UNIVERSITY OF VICTORIA CHEMISTRY 102 Midterm Test 2 March 13, pm (60 minutes) DISPLAY YOUR STUDENT ID CARD (ONECard) ON TOP OF YOUR DESK NOW

Version B UNIVERSITY OF VICTORIA CHEMISTRY 102 Midterm Test 2 March 13, 2015 5-6 pm (60 minutes) Version B DISPLAY YOUR STUDENT ID CARD (ONECard) ON TOP OF YOUR DESK NOW Answer all multiple choice questions