Dr Peter Wipf Chemistry 0310 1 18 2012 Name SID Signature Points 300 Sample Exam Problem A B C D E F G H Good Luck Points CHEM 0310 Page 2 A 30 points i Compare and contrast the Lewis structures of nitromethane CH3NO2 and methylnitrite CH3ONO ii Write at least 2 resonance forms for each molecule iii Based on your examination of the resonance forms what can you say about the polarity and bond order of the two NO bonds in each substance CHEM 0310 Page 3 B 30 points What kind of a C C bond length in would you expect for the dianion of ethene e g an ethene 2 molecule where two additional electrons are injected into the bond Rationalize your conclusion graphically with an orbital diagram for ethene 2 CHEM 0310 Page 4 C 45 points The following structure shows a natural product that my research group has synthesized a few years ago i Assign the hybridization at all carbon atoms and ii estimate the bond distance of all unique bonds iii What functional groups do you recognize O O H N O OH LL C10037 CHEM 0310 D Page 5 30 points Which of the following structures violate the octet rule H H N H O O Cl O H H H C C H C H H H Br P Br Br H H H H H E 40 points Draw a Newman projection of the gauche conformation of butane and explain the reasons for its energetic destabilization by how much vs the antiperiplaner conformation CHEM 0310 Page 6 F 45 points i Determine whether each species in the following equations is acting as a Br nsted acid or base and label it ii Indicate whether the equilibrium lies to the left or the right iii Estimate K for each equation using the Table copied on the next page a H2O HCN H3O CN b CH3O NH3 CH3OH NH2 c CH3COO HF CH3COOH F CHEM 0310 Page 7 CHEM 0310 G Page 8 30 points Use orbitals to explain the hyperconjugative stabilization of the ethyl radical CHEM 0310 Page 9 H 50 points Write in full the mechanism for monobromination of methane Clearly indicate initiation propagation and termination steps