Chem Midterm # 1

A reaction is found to have an activation energy of 108 kJ/mol. If the rate constant for this reaction is 4.60 x 10-6 s-1 at 275 K, what is the rate constant at 366 K?A) 0.580 s-1B) 11.7 s-1C) 1.85 x 10-4 s-1D) 5.40 x 10-5 s-1E) 1.72 s-1

A) 0.580 s-1

Which of the following statements is FALSE?A) The half life of a first order reaction is dependent on the initial concentration of reactant.B) It is not possible to determine the rate of a reaction from its balanced equation.C) The average rate of a reaction decreases during a reaction.D) None of the statements is false.E) Zero order reactions are not dependent on concentration.Note if you chose �a�, that is acceptable since in the case of zero order reaction that statement is false,and it does not specify the reaction order.

A) Teh half life of a first order reaction is dependent on the intial concentration of reactant.

Which of the following reactions would you predict to have the smallest orientation factor?A) X2 + Y2 >> 2 XYB) N + O2 >> NO2C) All of these reactions should have nearly identical orientation factors.D) NOCl2 + NO >> 2 NOClE) N2 + O2 >> 2 NO

D) NOCl2 + NO >> 2 NOCl

What is the overall order of the following reaction, given the rate law?2 X + 3 Y >> 2 Z Rate =k[X]1[Y]2a) 3rd orderb) 5th orderc) 2nd orderd) 1st ordere) 0th order

a) 3rd order

Consider the following reaction, equilibrium concentrations, and equilibrium constant at a particulartemperature. Determine the equilibriumconcentration of H2O(g).C2H4(g) + H2O(g) ? C2H5OH(g) Kc = 9.0 x 103[C2H4]eq = 0.015 M [C2H5OH]eq = 1.69 MA) 1.68 MB) 80. MC) 0.013 MD) 1.0 ME) 9.9 x 10-7 M

C) 0.013 M

What are the units of k in the following rate law?Rate = k[X]2[Y]A) 1 M3sB) M2sC) 1 Ms2D) 1 M2sE) M2s

D) 1 M2s

The first-order decomposition of cyclopropane has a rate constant of 6.7 x 10-4 s-1. If the initialconcentration of cyclopropane is 1.33 M, what is the concentration of cyclopropane after 644 s?A) 0.15 MB) 0.43 MC) 0.86 MD) 0.94 ME) 0.67 M

C) 0.86

The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 x 10-15 s-1 at 298 K and a rate constant of 8.66 x 10-7 s-1 at 425 K. Determine the activation energy for this reaction. A) 127 kJ/molB) 417 kJ/molC) 240. kJ/molD) 338 kJ/molE) 160. kJ/mol

E) 160. kJ/mol

Write a balanced chemical equation that corresponds to the following equilibrium constant expression.K = [F-][H3O+] [HF]A) F-(aq) + H3O+(aq) ? HF(aq) + H2O(l)B) HF(aq) ? F-(aq) + H3O+(aq)C) HF(aq) + H2O(l) ? F-(aq) + H3O+(aq)D) F-(aq) + H3O+(aq) ? HF(aq)E) H+(aq) + OH-(aq) ? H2O(l)

C) HF(aq) + H2O(l) ? F-(aq) + H3O+(aq)

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled?Rate = k[X][Y]2A) The rate of reaction will increase by a factor of 5.B) The rate of reaction will remain unchanged.C) The rate of reaction will decrease by a factor of 2.D) The rate of the reaction will increase by a factor of 4.E) The rate of reaction will increase by a factor of 2.

D) The rate of the reaction will increase by a factor of 4.