See the Bulletinboard about the revised due date for this PS

1. Draw a Newman projection of 2-methylbutane about the C₂-C₃ axis. Predict the

energy for the eclipsed and staggered conformations. Which one is the lowest in

energy and by how much over its nearest competitor? [H/H, eclipsed, 1.0 kcal/mol;

CH₃/H eclipsed, 1.4 kcal/mol; CH₃/CH₃, eclipsed, 2.5 kcal/mol; CH₃/CH₃,

gauche, 0.9 kcal/mol.]

2. Estimate the heat of formation (DH_f^o) of n-octane.

3. Write a balanced equation for the combustion of C₆H₁₄. How much heat is evolved

in the combustion of 2,2-dimethylbutane? How much less/more heat is evolved in

the oxidation of its isomer n-hexane? Use Appendix I.

4. 2-Methylbutane forms four monochloro compounds upon free radical chain

chlorination. Draw their structures. Using the data on pg. 110 (SHK), calculate the

percentage of each alkyl chloride formed.

5. Compound A, C₅H₁₂, forms a single compound B, C₅H₁₁Br, upon free radical

bromination. What are the structures of A and B? Write a free radical chain

mechanism for this reaction. [Include initiation and propagation steps].

6. Calculate the heat of formation of ethyl iodide using the information in Appendices 1

and II.

7. Write a free radical chain reaction for the formation of ethyl chloride from ethane.

Calculate the heat of reaction for each of the propagation steps and for the overall

reaction using heats of formation [Appendix I].

8. Solve #7 using the bond dissociation energy method [Appendix II].

9. Calculate the degrees of unsaturation (rings and multiple bonds) in the following

compounds: C₆H₁₁Br, C₁₁H₁₀O, C₈H₇N, and C₁₂H₁₄BrClN₂O.