EM 233, Fall 2015 PRITED FIRST AME answer PRITED LAST AME Midterm #1 key ASU ID or Posting ID Ian R. Gould Person on your LEFT (or Aisle) PRIT YUR AME EA PAGE! READ TE DIRETIS AREFULLY! USE BLAK PAGES AS SRAT PAPER work on blank pages will not be graded... WRITE LEARLY! MLEULAR MDELS ARE ALLWED D T USE RED IK Person on your RIGT (or Aisle) 1 /14... 2 /30... 3 /24... 4 /15... 5 /48... 6 /30... 7 /14... D'T EAT, USE MM SESE! Li Be B F e a Mg Extra redit /5 e Al Si P S l Ar K a Sc Ti V r Mn Fe o i u Zn Ga Ge As Se Br Kr Rb Sr Y Zr b Mo Tc Ru Rh Pd Ag d In Sn Sb Te I s Ba Lu f Ta W Re s Ir Pt Au g Tl Pb Bi Po At Rn (cm -1 ) amine alcohol (, ppm) small range range of values broad peak R 2 R R 11 220 R 3300 variable and condition dependent, ca. 2-6 10 200 3000 3100 9 180 2720 2820 2 peaks Aromatic Ar mainly 8-6.5 8 160 usually strong 7 140 6 120 R R 2 R 2 5 100 Xe Infrared orrelation hart Total (incl Extra) /175+5 2 2 4 80 R Interaction Energies, kcal/mol Eclipsing / ~1.0 /Me ~1.4 Me/Me ~2.6 Me/Et ~2.9 1600 1660 1680 2200 R broad with spikes ~3300 1735 2850 2960 1600 broad ~3300 2200 1710 R2 broad ~3000 1650 3500 3000 2500 2000 1500 MR orrelation harts 2 X R 2 R 2 3 60 2 3 2 40 X Gauche Me/Me ~0.9 Et/Me ~0.95 i-pr/me ~1.1 t-bu/me ~2.7 Approximate oupling onstants, J (z), for 1 MR Spectra Alkyl 3 Y > 2 Y > 1 Y Alkyl ~10 ~2 ~15 1 20 ~8 ~2 ~7 3 Y > 2 Y > 1 Y 0 0 Aromatic R 2
EMISTRY 233, Fall 2015, MIDTERM #1-2 - AME Question 1 (14 pts.) a) Give a line-angle structure for the following condensed formula. Do not forget to add all nonbonding electrons where appropriate. ( 3 2 ) 2 ( 2 ) 2 2 the graders do not get an absolute grading rubric for my tests, there are always too many possible ways to get partial credit in my exams, the guidelines in blue therefore are guidelines LY ~3 pts each for the functional groups -2pts for incorrect alkyl groups -3pts for this at the end: Question 2 (30 pts.) Directly TP of the structures below a) Draw a picture of the Ψ or Ψ 2 as requested, for the indicated orbitals b) learly indicate the atomic orbital or orbitals that you used to construct the requested orbitals c) For each drawing, clearly indicate the positions of any nodes, or locations of zero probability of finding the electrons, as appropriate to the question nodes 3 Ψ 2 for the - π M.. p A.. (carbon) p A.. (oxygen) zero probability incorrect sizes -2pts nodes sp3 () sp () Ψ for the σ M.. l Ψ for the -l σ* M.. sp3 A.. (carbon) p A.. (chlorine) forgot A..s = -2pts did the wrong question (wrong bond) = 7 pts maximum did bonding instead of anti-bonding or vica versa 7pts max Extra redit (5 pts). ne of the factors that contributes to the "stiffness" of the poly-peptide chains in proteins is... the wavefunctions the geometrical isomers resonance the ester functional groups
EMISTRY 233, Fall 2015, MIDTERM #1-3 - AME Question 3 (24pts.) For the structure shown on the right: a) give the hybridization for the nitrogen atom b) list all of the valence atomic orbitals formally associated with this nitrogen atom and give a brief description of how the nitrogen atom uses each orbital, e.g. p atomic orbital used to make a sigma bond to chlorine (this is obviously not correct, it is just to indicate how to answer this question) too many options for a rubric, generally half correct = half points there were 4 questions JUST LIKE TIS E on the problem set the has an hybrid A.. containing one pair of non-bonding electrons 120 the has an hybrid A.. that is used to build the σ-bond to the hydrogen atom the uses an hybrid A.. to build the σ-bond to carbon, which contains one of the pairs of electrons in the = double bond the uses an unhybridized p A.. to build the π-bond to carbon, which contains the second of the pairs of electrons in the = double bond c) Give the approximate -- bond angle indicated in the structure above with the arrow, assign the geometry around the nitrogen atom, AD, give a BRIEF explanation (2-3 sentences MAX.) for your choice of geometry that includes the terms "energy of the electrons", "VSEPR", "electron domains". there are 3 domains of electrons around the nitrogen, VSEPR requires a trigonal planar-like geometry to minimize the total energy of the electrons, WEVER, the nitrogen only has 2 atoms attached to it and the position of the non-bonding electrons cannot be determined with certainty, the geometry can only be defined as bent students will probably give a less detailed explnation than this, which is K, just so long as it is correct and includes the FUR required items in bold above Question 4 (15 pts.) ircle and identify all functional groups in the following structures, ignore alkyl groups. aromatic carboxylic acid alcohol aromatic amide ibuprofen the active ingredient in Motrin acetaminophen the active ingredient in Tylenol
EMISTRY 233, Fall 2015, MIDTERM #1-4 - AME Question 5) (48 pts.) For the molecular formula 3 6 2 a) Give the degrees of unsaturation 1 degree of unsaturation b) Draw EIGT structural isomers for 3 6 2 that obey the normal rules of valence for each atom. Include all non-bonding electrons. You can draw Lewis structures or line-angle structures (your choice). If you draw line-angle structures, don't forget to include the atoms that are normally included as part of the functional groups. there are MAY more than these! c) Draw TW PAIRS of stereoisomers for 3 6 2 that obey the normal rules of valence for each atom. Include all non-bonding electrons. You can draw Lewis structures or lineangle structures (your choice). If you draw line-angle structures, don't forget to include the atoms that are normally included as part of the functional groups. D T ILUDE AY STRUTURES in part c) TAT WERE DRAW AS PART F YUR ASWER T PART b) F TIS QUESTI!! etc.
EMISTRY 233, Fall 2015, MIDTERM #1-5 - AME Question 6) (30 pts) For the structure provided: a) Draw ALL reasonable missing resonance contributors b) Draw the curved arrow-pushing that indicates how the electrons are delocalized c) give the UMBER F ELETRS that are delocalized d) Indicate which is the MAJR resonance contributor and give a BRIEF EXPLAATI for your choice. If there are equal major contributors, indicate so. e) Include resonance arrows and brackets to complete your description of the final structure f) Based on the resonance contributors you drew, give the "actual" resonance hybrid structure. Indicate the atoms that have a partial charge, do not worry about determining absolute partial charges, just use the charge notation. SIX electrons delocalized the major resonance contributor has the negative charge in the more electronegative nitrogen atom major g) n the structure below (same one as above), give the hybridization of EVERY ARB ATM and also the ITRGE ATM. Take ALL of the resonance contributors your drew above into account when determining hybridizations. sp sp sp3 "actual" hybrid structure sp3 1pt each Question 7) (14 pts) ne of the two carbon atoms in the = double bond in the structure below has a small partial negative charge. Draw a MIR resonance contributor that illustrates which carbon this is, and clearly indicate the carbon that has this small partial negative charge. Include curved arrow pushing, resonance arrows and resonance brackets. TIS carbon has the small partial negative charge