4) What is the order of the reaction with respect to ClO2? 4) A) 2 B) 1 C) 4 D) 0 E) 3

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1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 1) 2NO2 2NO + O2 In a particular experiment at 300 C, [NO2] drops from to M in 100 s. The rate of disappearance of NO2 for this period is M/s. A) 0.35 B) C) D) E) ) Which one of the following is not a valid expression for the rate of the reaction below? 2) 4NH3 + 7O2 4NO2 + 6H2O A) 1 [NO2] 4 t B) - 1 [NH3] 4 t C) - 1 [O2] 7 t D) 1 [H2O] 6 t E) All of the above are valid expressions of the reaction rate. 3) The rate law of a reaction is rate = k[d][x]. The units of the rate constant are. 3) A) mol L-1s-2 B) mol L-1s-1 C) L2 mol-2s-1 D) L mol-1s-1 E) mol2 L-2s-1 The data in the table below were obtained for the reaction: 2 ClO2 (aq) + 2 OH- (aq) ClO3 - (aq) + ClO2 - (aq) + H2O (1) Experiment Number [ClO2] (M) [OH-] (M) Initial Rate (M/s) ) What is the order of the reaction with respect to ClO2? 4) A) 2 B) 1 C) 4 D) 0 E) 3 1

2 5) The rate law for a reaction is 5) rate = k [A][B]2 Which one of the following statements is false? A) The reaction is second order overall. B) If [B] is doubled, the reaction rate will increase by a factor of 4. C) The reaction is second order in B. D) The reaction is first order in A. E) k is the reaction rate constant 6) The rate constant of a first-order process that has a half-life of 225 s is s-1. 6) A) B) C) 12.5 D) E) ) The rate of a reaction depends on. 7) A) collision orientation B) collision energy C) collision frequency D) all of the above E) none of the above 8) In the energy profile of a reaction, the species that exists at the maximum on the curve is called the. A) activated complex B) product C) activation energy D) enthalpy of reaction E) atomic state 9) In the Arrhenius equation, 8) 9) k = Ae-Ea/RT is the frequency factor. A) A B) k C) R D) Ea E) e 10) In general, as temperature goes up, reaction rate. 10) A) goes up if the reaction is exothermic B) goes up regardless of whether the reaction is exothermic or endothermic C) goes up if the reaction is endothermic D) stays the same if the reaction is first order E) stays the same regardless of whether the reaction is exothermic or endothermic 2

3 11) For the elementary reaction 11) NO3 + CO NO2 + CO2 the molecularity of the reaction is, and the rate law is rate =. A) 2, k[no3][co] B) 2, k[no3][co]/[no2][co2] C) 4, k[no3][co][no2][co2] D) 4, k[no2][co2]/[no3][co] E) 2, k[no2][co2] 12) The rate law of the overall reaction 12) A + B C is rate = k[a]2. Which of the following will not increase the rate of the reaction? A) increasing the concentration of reactant A B) increasing the temperature of the reaction C) adding a catalyst for the reaction D) increasing the concentration of reactant B E) All of these will increase the rate. 13) At equilibrium,. 13) A) the rates of the forward and reverse reactions are equal B) all chemical reactions have ceased C) the rate constants of the forward and reverse reactions are equal D) the value of the equilibrium constant is 1 E) the limiting reagent has been consumed 14) Which one of the following will change the value of an equilibrium constant? 14) A) varying the initial concentrations of products B) adding other substances that do not react with any of the species involved in the equilibrium C) changing temperature D) varying the initial concentrations of reactants E) changing the volume of the reaction vessel 15) Given the following reaction at equilibrium, if Kc = 6.44 x 105 at C, Kp =. 15) 2NO (g) + O2 (g) 2NO2 (g) A) 3.67 x 10-2 B) 1.56 x 104 C) 6.44 x 105 D) 2.67 x 107 E) 2.66 x 106 3

4 16) Which of the following expressions is the correct equilibrium-constant expression for the reaction below? 16) (NH4)2Se (s) 2NH3 (g) + H2Se (g) A) [NH3]2[H2Se] B) [NH3][H2Se] / [(NH4)2Se] C) [(NH4)2Se] / [NH3]2[H2Se] D) 1 / [(NH4)2Se] E) [NH3]2[H2Se] / [(NH4)2Se] 17) The equilibrium constant for the gas phase reaction 17) N2 (g) + 3H2 (g) 2NH3 (g) is Keq = at 300 C. At equilibrium,. A) only products are present B) reactants predominate C) products predominate D) roughly equal amounts of products and reactants are present E) only reactants are present 18) The equilibrium constant for reaction 1 is K. The equilibrium constant for reaction 2 is. 18) (1) SO2 (g) + (1/2) O2 (g) SO3 (g) (2) 2SO3 (g) 2SO2 (g) + O2 (g) A) -K2 B) K2 C) 1/K2 D) 2K E) 1/2K 19) Which of the following statements is true? 19) A) Q is the same as Keq when a reaction is at equilibrium. B) Q does not change with temperature. C) K does not depend on the concentrations or partial pressures of reaction components. D) Keq does not change with temperature, whereas Q is temperature dependent. E) Q does not depend on the concentrations or partial pressures of reaction components. ESSAY. Write your answer in the space provided or on a separate sheet of paper. 20) Pure benzene has a freezing point of 5.5 oc and a boiling point of 80.1 oc. What are the expected freezing point and boiling point for a 0.15 m solution of a nonvolatile solute in benzene? For benzene, Kf = 5.12 oc/m and Kb = 2.53 oc/m. ÄTf = (5.12 oc/m)(0.15 m) = 0.77 oc Tf soln = Tf ÄTf = ( ) oc = 4.7 oc ÄTb = (2.53 oc/m)(0.15 m) = 0.38 oc Tb soln = Tb + ÄTb = ( ) oc = 80.5 oc 4

5 21) For the reaction 2 NOCl(g) 2 NO(g) + Cl2(g) The rate constant, k, is 2.6 x 10 8 L/mol _s at 300 K and 4.9 x 10-4 L/mol _s at 400 K. What is the activation energy, Ea, of the reaction? MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 22) Consider the following equilibrium. 22) 2 SO2 (g) + O2 (g) 2 SO3 (g) The equilibrium cannot be established when is/are placed in a 1.0-L container. A) 0.25 mol SO2 (g) and 0.25 mol O2 (g) B) 0.25 mol of SO2 (g) and 0.25 mol of SO3 (g) C) 0.75 mol SO2 (g) D) 1.0 mol SO3 (g) E) 0.50 mol O2 (g) and 0.50 mol SO3 (g) 5