SOLVED

41) Define activation energy. A) the difference between the energy of the products and reactants B) the energy difference between the maximum energy of reaction and the energy of the products C) the minimum total kinetic energy that molecules must bring to their collisions for a chemical reaction to occur D) the total kinetic energy of molecules in collisions E) the total kinetic energy of molecules in a system 42) According to the collision theory in gaseous molecules, collision frequency is ________ and reaction is ________ because ________. A) low, low, molecules are so far apart B) high, high, each collision results in a reaction C) low, low, molecules must collide before they can react D) high, relatively low, only a fraction of the collisions lead to a reaction E) low, high, molecules are moving so fast that each reaction causes many others 43) Which statement is INCORRECT? A) Activation energy is the same for forward and reverse reaction. B) If the forward reaction is endothermic, the reverse will be exothermic. C) In an endothermic reaction, activation energy is usually greater than the enthalpy. D) An activated complex has higher energy than any molecule contributing to it. E) The activated complex will be the highest on the energy profile. 44) A factor that decreases the activation energy for a reaction: I)decreases the rate constant II)increases the rate constant III)has no effect on the rate constant IV)makes the product yield increase V)might be a catalyst A) I and IV B) II and IV C) I, IV, and V D) IV and III E) II and V 45) What is the rate constant at 305 K for the reaction: 2N2O5 → 2N2O4 + O2, if k = 3.46 × 10-5 s-1 at 298 K and Ea = 106 kJ/mol? A) 2.4 × 10-5 s-1 B) 4.8 × 10-5 s-1 C) 6.0 × 10-5 s-1 D) 1.2 × 10-5 s-1 E) 9.2 × 10-5 s-1 46) In the Arrhenius equation, ln k = -Ea/RT + ln A, the symbol A denotes: A) the initial concentration of A B) the activation energy C) the rate constant D) a constant that represents the frequency of collisions with the proper orientation and other steric conditions favorable for a reaction E) the absolute temperature 47) Activation energy is: I)the minimum kinetic energy required for each molecule in a collision to produce a reaction. II)the minimum total kinetic energy required for the molecules in a collision to produce a reaction. III)a factor in determining the rate of a reaction. IV)high for fast reactions. A) I and III B) I, III, and IV C) II, III D) II and IV E) II, III, and IV 48) For the reaction: 2N2O5(g) → 4NO2(g) + O2(g) the rate law is:   = k[N2O5] At 300 K, the half-life is 2.50 × 104 seconds and the activation energy is 103.3 kJ/mol. What is the rate constant at 310 K? A) 2.78 × 10-5 s-1 B) 7.29 × 10-6 s-1 C) 7.29 × 10-8 s-1 D) 3.70 × 10-5 s-1 E) 1.05 × 10-4 s-1 49) For the reaction: 2N2O5(g) → 4NO2(g) + O2(g) the rate law is:   = k[N2O5] At 300 K, the half-life is 2.50 × 104 seconds and the activation energy is 103.3 kJ/mol. What is the rate constant at 350 K? A) 4.78 s-1 B) 2.79 × 10-5 s-1 C) 6.38 × 1016 s-1 D) 7.47 × 10-8 s-1 E) 1.03 × 10-2 s-1 50) For the reaction: 2N2O5(g) → 4NO2(g) + O2(g) the rate law is:   = k[N2O5] At 300 K, the half-life is 2.50 × 104 seconds and the activation energy is 103.3 kJ/mol. What is the half-life at 310 K? A) 2.49 × 104 s B) 9.51 × 104 s C) 9.51 × 106 s D) 6.57 × 103 s E) 1.87× 10-1 s