CHM 1046 Exam 2 Questions With Detailed Correct Answers

T/F: At equilibrium, the rate constant for the forward and reverse reaction are equal - correct answers False T/F: The half-life (t1/2) of a reaction is always independent of concentration - correct answers False T/F: Adding impurities to an amorphous solid lowers its melting temperature - correct answers True T/F: Increasing activation energy decreases the rate of a reaction - correct answers True T/F: Transition states are typically more stable than intermediates. - correct answers False T/F: For a second order reaction, the plot of ln[conc] vs. time is linear - correct answers False T/F: Assuming the salt dissolves completely, a .010 M aqueous CaCl2 solution will have the same boiling point as a .015 M aqueous NaCl solution - correct answers True T/F: Doubling the temperature of a reaction doubles the rate - correct answers False T/F: Adding a catalyst increases the yield of the product. - correct answers False T/F: For the reaction A+B -- 2C+D, C is generated at the same rate that A is consumed - correct answers False T/F: A very large equilibrium constant (K) tells you the reaction will be fast - correct answers False T/F: Measuring the rate constant at two different temperatures can be used to determine Ea. - correct answers True T/F: At equilibrium, the rate of the forward and reverse reactions are equal - correct answers True T/F: Reaction rates are independent of the size and shape of the molecule - correct answers False T/F: Ocean water will freeze at a colder temperature than pure water. - correct answers True The Kc for the equilibrium 3Fe(s) + 4H2O(g) -- Fe3O4(s) + 4H2(g) is 4.3*10^6 at 700 K. What is the Kp for this equilibrium? A. 7.1*10^3 B. 2.6*10^9 C. 4.3*10^6 D. there is no Kp value - correct answers C. 4.3*10^6 What are the units on "k" for the following rate law: rate=k[A]^3[B]^2 A. s^-1 B. M s^-1 C. M^-1 s^-1 D. M^-4 s^-1 E. M^-5 s^-1 - correct answers D. M^-4 s^-1 Adding a catalyst to a reaction: A. Increases the rate of the forward reaction B. Increases the rate of the reverse reaction C. Changes the value of K D. All of the above E. Both A and B - correct answers E. Both A and B The 2017 Nobel prize in chemistry was awarded for: A. cyro-electron microscopy B. discovering the mechanism for autophagy C. the synthesis of molecular machines D. measuring gravity waves - correct answers A. cyro-electron microscopy What effect does doubling the initial concentration of a reactant have on the half-life of a second order reaction? A. The half-life will be halved B. The half-life is independent of concentration C. The half-life becomes 0 D. The half-life will be doubled - correct answers A. The half-life will be halved The rate of a reaction depends on: A. the collision energy B. the orientation of the molecules C. the frequency of the collisions D. all of the above E. a and b only - correct answers D. all of the above For the equilibrium A -- B, at a given temperature, suppose the rate constant for the forward reaction is two times larger that the rate constant of the reverse reaction. Is the value of the equilibrium constant: A. K 1 B. K = 1 C. K 1 D. can't be answered without concentrations - correct answers A. K 1 Sulfur oxides are major air pollutants. The reaction between sulfur dioxide and oxygen can be written at least two ways: 1. SO2 (g) + 1/2O2 (g) -- SO3 (K1) 2. 2SO2 (g) + O2 (g) -- 2SO3 (g) (K2) How are the two equilibrium expressions related?