CHEM 112 Exam 2 Review Questions With Accurate Answers Solved

Select the correct equilibrium constant expression for the reaction: N2(g) + 3H2(g) ⇄ 2 NH3(g) - correct answers [NH3 ] 2 K= ---------------- [N2 ][H2 ] 3 In the Kinetics of Smell experiment, one of the experiments involved varying the concentration of the acetic acid. Here's a set of student data from that lab: What is the impact of increasing the concentration of acetic acid on the rate as measured by the average time in seconds it took to smell the ester? (exam 3 material) - correct answers The rate increased as the acid concentration increased. Given the following balanced chemical equation, how is the rate of consumption of bromide ion related to the rate of production of water? (note that the " delta triangle" could be written as "d" as well) 5Br− (aq) + BrO3 − (aq) + 6H+ (aq) → 3Br2(aq) + 3H2O(l) (exam 3 material) - correct answers - 1/5( ∆[Br- ] / ∆t_) = 1/ 3 (∆[H2O] /∆t) Use the diagram below which depicts a reaction A-- B for questions 10 and 11. Describe how the reaction releases or absorbs energy. - correct answers It absorbs 50 kJ of energy (it's endothermic) Consider the reaction, 2 N2O5(g) → 4 NO2(g) + O2(g) What is the value of the rate constant, k, for this reaction? (exam 3 material) - correct answers 6.96 × 10^−3 s ^−1 Consider the reaction A + B --products. From the following data obtained at a certain temperature, determine the rate law for the reaction. (exam 3 material) - correct answers Rate = k[A] Molecules must overcome a barrier called the ____________ if they are to react (exam 3 material) - correct answers Activation Energy A chemical reaction has the rate law: Rate = k[A]^x . Determine is the order of the reaction (x in the equation) if the rate increases by a factor of four when the concentration of the reactant is doubled. (exam 3 material) - correct answers Second Order The graph below shows concentration versus time for the reaction A--B. Which vertical line, numbered 1 through 4, indicates where equilibrium occurs? - correct answers Line 4: lines are parallel to each other not touching in an intersection so don't be fooled When a chemical system has reached equilibrium: - correct answers the rate of the forward reaction is equal to the rate of the reverse reaction. Use the diagram below which depicts a reaction A--B for questions 10 and 11. What is the activation energy? (Note PE stands for Potential Energy) (exam 3 material) - correct answers 200 kJ