Exam 4: The Study of Chemical Reactions

Rank the free radicals (I-III) shown below in order of decreasing stability (i.e., from most stable to least stable).

Which of the following is true for the initiation step of a free radical chlorination reaction?

What is the name of the major monobrominated product which results when 3-methylpentane is subjected to Br₂/hν conditions?

When compound I, C₇H₁₆, was treated with chlorine and light it yielded 3 monochlorination products that could be separated by chromatography. Two of the products were primary alkyl halides and the other was a secondary alkyl halide. Provide a possible structure for compound I.

Given that the theoretical reaction below was found to be second order and bimolecular, provide a rate equation for the reaction. A-B + C-D → A-C + B-D

Which of the following is a carbene?

When the reaction between methane and chlorine is photochemically initiated, which of the following compounds cannot be formed through a termination reaction?

Draw all monochlorination products expected from reaction of chlorine with 3,4-dimethylhexane. Circle the major product.

Consider the reaction of A being converted into B at 25°C. If the ΔG° of this reaction is the K_eq is ________ and the % conversion is ________.

Describe the hybridization of the cationic center and predict the CCC bond angle in (CH₃)₃C⁺.

Explain the significance of the frequency factor A in the Arrhenius equation.

Which of the following reactive intermediate species maintains sp³ hybridization?

Given a ΔG° of -8.0 kJ/mol at 25°C, calculate the corresponding K. [R = 8.314 J/K∙ mol]

Which of the following species is not formed through a termination reaction in the chlorination of methane?

Energy is ________ when bonds are formed and is ________ when bonds are broken; therefore, bond dissociation energies are always ________.

Consider the transformation of A to B (i.e., A → B). If at equilibrium at 25°C the concentration of A is 20% of the initial concentration of A, determine the value of (in kcal/mol) for this reaction. R = 1.987 cal/mol∙K.

Consider the one-step conversion of F to G. Given that the reaction is endothermic by 5 kcal/mol and that the energy difference between G and the transition state for the process is 15 kcal/mol, sketch a reaction-energy diagram for this reaction. Make sure to show how the given energy differences are consistent with your sketch.

Write a detailed, stepwise mechanism for the following reaction.

What term describes the highest-energy structure in a molecular collision which leads to reaction?

Consider the reaction energy diagram shown below. Label the axes. a. Which points on the curve indicate transition states? Label them with A, B, etc. b. Is the overall reaction exothermic or endothermic?