<p> Chemistry 116: General Chemistry Syracuse University Project Advance Exam #1, Spring 2001</p><p>Name Date </p><p>The last page of this examination is a periodic table [Gas constant = 0.00831 kJ/mol K; 1 faraday = 96.5 kJ/V mol e-; Nernst eq. constant = 2.303RT/F = 0.0592 V mol (T = 25 ˚ C).] (1) The following reaction was studied by the method of initial rates: CO + Cl2 ----> COCl + Cl</p><p>[CO]0 (mol/L) [Cl2]2 (mol/L) Rate (mol/Ls)</p><p>1.00 x 102 1.00 x 102 6.60 x 103 2.00 x 102 1.00 x 102 1.32 x 103 3.00 x 102 1.00 x 102 1.98 x 103 1.00 x 102 2.00 x 102 2.64 x 103 2.00 x 102 1.00 x 102 1.19 x 103</p><p>What is the rate law?</p><p>2 (a) Rate = k[Cl2] (b) Rate = k[Cl2][CO] 2 (c) Rate = k[Cl2] [CO] 2 2 (d) Rate = k[Cl2] [CO] (e) Rate = k[CO]</p><p>(2) For the reaction, A + B ------> products, the following data were obtained:</p><p>Initial Rate (mol/Ls) 0.030 0.059 0.060 0.090 0.090 [A]0 (Mol/Ls) 0.10 0.20 0.20 0.30 0.30 [B]0 (mol/Ls) 0.20 0.20 0.30 0.30 0.50</p><p>What is the experimental rate law? (a) Rate = k[A] (b) Rate = k[B] (c) Rate = k[A][B] (d) Rate = k[A]2[B] (e) Rate = k[A][B]2</p><p>(3) Tabulated below are initial rate data for the reaction:</p><p>CHE 116 1 Spring 2000 Exam Questions 3- - 4- 2{Fe(CN)6} + 2I ------> 2{Fe(CN)6} + I2</p><p>3- - 4- Run [{Fe(CN)6} ]0 [I ]0 [{Fe(CN)6} ]0 [I2]0 Initial Rate (M/s]</p><p>1 0.01 0.01 0.01 0.01 1 x 10-5 2 0.01 0.02 0.01 0.01 2 x 10-5 3 0.02 0.02 0.01 0.01 8 x 10-5 4 0.02 0.02 0.02 0.01 8 x 10-5 1 0.02 0.02 0.02 0.02 8 x 10-5</p><p>What is the value of k? (a) 107 M-5/s (b) 103 M-3/s (c) 10 M-2/s (d) 50 M-2/s (e) none of these</p><p>(4) Tabulated below are initial rate data for the reaction:</p><p>3- - 4- 2{Fe(CN)6} + 2I ------> 2{Fe(CN)6} + I2</p><p>3- - 4- Run [{Fe(CN)6} ]0 [I ]0 [{Fe(CN)6} ]0 [I2]0 Initial Rate (M/s]</p><p>1 0.01 0.01 0.01 0.01 1 x 10-5 2 0.01 0.02 0.01 0.01 2 x 10-5 3 0.02 0.02 0.01 0.01 8 x 10-5 4 0.02 0.02 0.02 0.01 8 x 10-5 1 0.02 0.02 0.02 0.02 8 x 10-5</p><p>What is the value of experimental rate law? 3- 2 - 2 4 2 (a) [I2]/t = k[{Fe(CN)6} ] [I ] [{Fe(CN)6} ] [I2] 3- 2 - 4 (b) [I2]/t = k[{Fe(CN)6} ] [I ][{Fe(CN)6} ][I2] 3- 2 - (c) [I2]/t = k[{Fe(CN)6} ] [I ] 3- - 2 (d) [I2]/t = k[{Fe(CN)6} ][I ] 3- - 4 (e) [I2]/t = k[{Fe(CN)6} ][I ][{Fe(CN)6} ]</p><p>(5) The reaction:</p><p>- + 1- H2SeO3(aq) + 6I (aq) + 4H (aq) ------> 2I3 (aq) + 3H2O(l) + Se(s) CHE 116 2 Spring 2000 Exam Questions was studied at 0° C by the method of initial rates.</p><p>+ - [H2SeO2]0 [H ]0 [I ]0 Rate</p><p>1.0 x 10-4 2.0 x 10-2 2.0 x 10-2 1.66 x 10-7 2.0 x 10-4 2.0 x 10-2 2.0 x 10-2 3.33 x 10-7 3.0 x 10-4 2.0 x 10-2 2.0 x 10-2 4.99 x 10-7 1.0 x 10-4 4.0 x 10-2 2.0 x 10-2 6.66 x 10-7 1.0 x 10-4 1.0 x 10-2 2.0 x 10-2 0.42 x 10-7 1.0 x 10-4 2.0 x 10-2 4.0 x 10-2 13.4 x 10-7 1.0 x 10-4 1.0 x 10-2 4.0 x 10-2 3.36 x 10-7</p><p>What is the rate law? + - (a) Rate = k[H2SeO3][H ][I ] + 2 - (b) Rate = k[H2SeO3][H ] [I ] + - 2 (c) Rate = k[H2SeO3][H ][I ] 2 + - (d) Rate = k[H2SeO3] [H ][I ] + 2 - 3 (e) Rate = k[H2SeO3][H ] [I ]</p><p>(6) What is the numerical value of the rate constant in the above problem (H2SeO3 reaction)? (a) 5.2 x 105 (b) 2.1 x 102 (c) 4.2 (d) 1.9 x 10-6 (e) none of these</p><p>(7) The rate for a particular reaction is k[A][B]2. If the initial concentration of B increases from 0.1 M to 0.3 M, by which factor does the initial rate increase? (a) 2 (b) 6 (c) 12 (d) 3 (e) 9</p><p>(8) In the reaction:</p><p>3A + B + C ------> D + E</p><p>CHE 116 3 Spring 2000 Exam Questions the rate law is:</p><p>-[A]/t = k[A]2[B][C]</p><p>-4 In an experiment, [B]0 = [C]0 = 1.00 M and [A]0 = 1.00 x 10 M</p><p>After 3.00 min, [A] = 3.26 x 10-5 M. Calculate k. (a) 6.23 x 10-3 L3/mol3 s (b) 3.26 x 10-5 L3/mol3 s (c) 1.15 x 102 L3/mol3 s (d) 1.00 x 108 L3/mol3 s (e) none of these</p><p>(9) For the reaction and information given above (3A + B + C ------> D + E), the half-life for this experiment is; (a) 1.11 x 102 s (b) 87.0 s (c) 6.03 x 10-3 s (d) 117 s (e) none of these</p><p>(10) For the reaction given above (3A + B + C ------> D + E), the concentration of [C] after 10.0 minutes is; (a) 1.00 M (b) 1.10 x 10-5 M (c) 0.330 M (d) 0.100 M (e) none of these</p><p>(11) For the reaction:</p><p>2A + B ------> products</p><p> the following mechanism is proposed:</p><p>A + B <======> M A + M ------> Products</p><p>Assuming that the second step is the rate-determining step and the first step is a fast equilibrium step, determine the rate law. Represent the rate constant in terms of k1, k-1, and k2.</p><p>2 Answer; rate = k1k2[A] [B]/k-1</p><p>(12) For the reaction described above (2A + B ------> products) and using the steady state approximation, determine the rate law.</p><p>2 Answer: rate = k1k2[A] [B]/(k-1 + k2 [A])</p><p>Chapter 15. Chemical Equilibrium CHE 116 4 Spring 2000 Exam Questions (13) Which statement about equilibrium in NOT true? (a) When a system is disturbed, it responds to restore equilibrium. (b) Equilibrium in molecular systems is dynamic, with two opposing processes balancing one another. (c) The value of the equilibrium constant for a reaction does not depend on the direction from which equilibrium is attained. (d) A system moves spontaneously toward a state of equilibrium (e) The equilibrium constant is independent of temperature.</p><p>(14) What is the mass action or equilibrium exprssion for the reaction below in terms of molar concentration?</p><p>P4(g) + 6H2(g) <======> 4PH3(g)</p><p>6 4 (a) [P4][H2] /[PH3] 4 6 (b) [PH3] /[P4][H2] (c) [PH3]/[H2][P4] 4 6 4 (d) [PH3] /[H2] [P4] (e) none of the above</p><p>(15) For the reaction,</p><p>CO(g) + Cl2(g) <======> COCl2(g)</p><p> at a particular temperature, K = 5.1 x 109 when all concentrations are expressed in moles/liter. Pure COCl2 is added to a 1.0 liter flask. At equilibrium it is found that 0.25 moles of COCl2 remain. What is the equilibrium concentration of CO? (a) 0.75 M (b) 1.4 x 10-5 M (c) 7.0 x 10-6 M (d) 4.9 x 10-11 M (e) none of the above</p><p>(16) Which reaction is an example of a homogeneous equilibrium? (a) MgCO3(s) <======> MgO(s) + CO2(g) (b) NaCl(s) <======> Na+(aq) + Cl-(aq) (c) 3H2(g) + N2(g) <======> 2NH3(g) (d) C(s) + CO2(g) <======> 2CO(g) (e) none of the above (17) Assume an ideal gas mixture for the following reaction:</p><p>2N2O(g) + N2H4(g) <======> 3N2(g) + 2H2O(g)</p><p>Initially, 0.10 mole of N2O and 0.25 mole of N2H4 are placed in a 10.0 liter container. If there are 0.06 moles of N2O at equilibrium, how many moles of N2 are present at equilibrium? (a) 0.09 (b) 0.04 (c) 0.06 (d) 0.02 CHE 116 5 Spring 2000 Exam Questions (e) none of the above</p><p>(18) When 2.0 moles of N2(g) and 4.0 moles of H2(g) are added to a 1.0 liter container, the following reaction occurs:</p><p>3H2(g) + N2(g) <======> 2NH3(g)</p><p>-2 2 The equilibrium concentration of NH3(g) = 0.68 m/L at 700° C. Calculate K (moles liter ) at 700° C for the formation of ammonia. (a) 3.6 x 10-3 (b) 1.4 x 10-1 (c) 1.1 x 10-2 (d) 5.0 x 10-2 (e) none of the above</p><p>(19) Ammonia is prepared industrially by the reaction,</p><p>N2(g) + 3H2(g) <======> 2NH3(g)</p><p> for which H° = -92.2 kJ and K (at 25° C) = 4.0 x 108. When the temperature is increased to 500° C, which of the following is true. (a) K for the equilibrium is larger at 500° C than at 25°C. (b) At equilibrium, more NH3 is present at 500° C than at 25° C. (c) Product formation (at equilibrium) is not favored as the temperature is raised. (d) The reaction of N2 with H2 to form ammonia is endothermic. (e) none of the above is true.</p><p>(20) For the reaction,</p><p>A(g) + B(g) <======> C(g) + D(g)</p><p> the gases A, B, C, and D are at equilibrium. If gas A is introduced, the value of K (a) increases because by adding A, more, products are made and the product to reactant ratio increases. (b) decreases because A is a reactant so the product to reactant ratio decreases. (c) does not change because A does not affect the product to reactant ratio. (d) does not change as long as the temperature is constant. (e) depends on whether the reaction is endothermic or exothermic. (21) For the following reaction,</p><p>PCl5(g) <======> PCl3(g) + Cl2(g)</p><p>H = -89 kJ. How can the equilibrium be shifted to the right? (a) add more PCl5. (b) decrease the pressure by changing the volume. (c) remove Cl2. (d) remove PCl3. (e) all of the above.</p><p>CHE 116 6 Spring 2000 Exam Questions (22) For the following reaction,</p><p>PCl5(g) <======> PCl3(g) + Cl2(g)</p><p> which of the following is FALSE? (a) Adding PCl3 to the container shifts the equilibrium to form more PCl5. (b) Increasing the temperature shifts the equilibrium to form more PCl3. (c) Decreasing the volume of the container shifts the equilibrium to form more PCl5. (d) Removing PCl5 from the container shifts the equilibrium to from more PCl3. (e) All of the above are true.</p><p>(23) Consider the following reaction which is involved in the catalytic destruction of ozone by chlorine atoms:</p><p>ClO(g) + O3(g) <======> Cl(g) + 2O2(g)</p><p>Kp = 2.5 x 106 atm at 25° C. In an experiment at 25° C, ClO(g) at 1.0 x 10-3 atm was mixed -5 with O3(g) at 2.0 x 10 atm in a rigid vessel. Calculate the equilibrium pressure of O3(g) and O2(g).</p><p>-17 -5 Answer: for O3, 1.3 x 10 atm; for O2, 4.0 x 10 atm</p><p>CHE 116 7 Spring 2000 Exam Questions</p>