Oh! Chem AAA midterm

<p>see what I did there with the Oh and the 3 A's</p>


<p>the only thing that I was wondering was did B (in BH3) have a nb orbital and what would it look like as sp hybridized?</p>

<p>what did you guys think?</p>

<p>lol-i couldnt believe that the MO was the hardest question for me on that exam..i was wondering about that too. i didnt think it had any nb but it seemed wrong-i put all six electrons in the sigma b-h bonding...<em>sigh</em></p>

<p>for 5b (pick the more stable carbocation-which structure did you circle as more stable?)</p>

<p>left (the one with the OCh3 at the complete bottom)...there were more resonance structures for the plus charge to move around....</p>

<p>that's what I put anyway</p>

<p>me too! yay! which two newman projections did you circle for lowest E staggered and eclipsed?</p>

<p>the two on the bottom left</p>

<p>did you put trans on page 1 for chair cyclohexane?</p>

<p>I kept second guessing ΔG change b/c he worded it differently than in the exam book. I put that it didn't change.</p>

<p>yeah i put trans-i almost didnt see the trans though until i drew in the assumed hydrogens! for G i calculated i think -1.2 and said equilibrium would lie forward. but i said no for where he asked would it be different actually (due to other forms of steric hindrance, diaxial interactions etc)</p>

<p>for the predict product/resonance structures what did you predict the first one was? product or res structure?</p>

<p>product, sigma bonds were broken (between the H and C) and only pi bonds can be broken in resonance </p>

<p>thank god for last minute studying huh...</p>

<p>wasn't your guy's midterm yesterday?</p>

<p>i thought it was unusually easy. i don't know if it was because i did the problem sets or what.</p>

<p>@ Batman:yeah</p>

<p>i think i said resonance for that one :(</p>

<p>other than that and the MO though, I thought it was easy too!</p>

<p>yup yup....w t f was up with the mo levels for oxygen....a 9th grade remedial chem student could have answered that?</p>

<p>Yah you think the midterm was easy until you get your midterm back....</p>

<p>why you gotta be like that man???! lol</p>

<p>Because that's how o-chem is hahaha I had frechet so I'm not sure how Pederon will be, but FYI watch out for the second midterm cuz it's a real killer.</p>

<p>^ for frechet the first midterm killed me.</p>

<p>i didnt think delta g would be different than what it was because there was no gauche or diaxial interactions unaccounted for...</p>

<p>heres what confused me though:
- how many valence e- does Na+ have?
- how to draw the BH3 wherein the B is sp hybridized
- was the multiple choice asking about radical stability just have to do with hyperconjugation?</p>

<p>I put zero for Na+, I looked it up and a couple of sites reference that it has none...but their was nothing directly answering the question</p>

<p>yeah i said 0 for na+ as well. i said hyperconjugation AND induction for the radical one....YIKES IM SCARED-im feeling worse and worse about this midterm...i was walking by latimer today and I saw pederson and the 3al gsis grading them and my stomach started turning.</p>

<p>for the ispropyl radical if we just drew in a substituent with an extra electron would that be wrong?</p>

<p>i think i have problems, i dont really know any other people that get as nervous and worked up as i do for midterms-maybe freshman but it seems like older students know how to deal better with the stress and i just dont know how even though i try to tell myself there are more important things in life:(</p>

<p>i dont think induction is a correct answer as induction is the process wherein one bond dipole induces a dipole in the other (look it up on wiki)..
for the isopropyl radical, it was just the isopropyl structure with an "R" group on the middle C and an extra, radical e-, on the middle C as well..</p>

<p>did you guys thing that the true delta G would be different? i thought it would be the same
also, how did you draw the BH3?</p>

<p>yeah..i put that delta G would be the same</p>

<p>for the raidcal, i put the i-pr with an 'r' on the end and a radical in between the branches....</p>

<p>i circled induction and hyperconj...i'm pretty sure that he said both played a role in class</p>

<p>don't get me started on BH3...i have no clue how a linear molecule could host 3 hydrogens....</p>