First Semester Organic Chemistry Five Sets of Practice Exams

Transcription

1 First Semester Organic Chemistry Five Sets of Practice Exams N Cl Prof. J. W. Keller i

2 Cover: Molecular orbital (MO) description of the transition state of the nucleophilic substitution reaction between ammonia and chloromethane. In the transition state the N-C bond is beginning to form, and at the same time the C-Cl bond is breaking. This diagram shows the non-bonding MO of ammonia, which is the electron pair donor, beginning to overlap with one end of the σ* MO of the C-Cl bond, which is the electron pair acceptor. This surface was generated using the Gaussian 03 ab initio program using the WebMO server at the University of Alaska Fairbanks Department of Chemistry and Biochemistry. Similar results could be obtained with yperchem or other quantum chemistry programs. ii

3 Table of Contents Five Semesters of Chem 321 Exams ( ) Including Chapters in McMurry s Organic Chemistry, 5 th and 6 th Editions Table of Contents... i Introduction... iii Typical Exam Reference Sheet (constants and equations)... iv Spectral Reference Tables... v Year Chapters Topic Page 2000 Quiz 1 1,2 Structure and bonding 1 5 th Ed Quiz 2 3,4 Alkanes 2 Quiz 4 7 Alkene Reactions 3 Quiz 5 8 Alkynes 4 Quiz 6 11 Nucleophilic Substitution 5 Quiz 7 12, 13 NMR, IR, and MS 6 Quiz 8 15 Benzene 8 our our our Final Quiz 1 1,2 Structure and bonding 30 5 th Ed Quiz 2 3,4 Alkanes 31 Quiz 3 5,6 Alkenes 32 Quiz 4 7 Alkene Reactions 33 Quiz 5 8 Alkynes 34 Quiz 6 9 Stereochemistry 35 Quiz 7 11 Nucleophilic Substitution 36 Quiz 8 12, 13 NMR, IR, and MS 37 Quiz 9 14 Conjugated Dienes 39 our our our Final (no quizzes given ) 6 th Ed Cover Page 61 our our our our Final i

4 2004 our th Ed our our our Final our our our our Final ii

5 Introduction This book is a complete set of quizzes and exams given in five semesters of Chemistry 321, Organic Chemistry I, at the University of Alaska Fairbanks in '00, '02, '03 and '04, and 06. Chem 321 is the first semester of a twosemester series dealing with the concepts, facts, and problem solving methods of organic chemistry. This course is lecture only. Organic chemistry laboratory is given as a separate course (Chem 324), which accompanies the 2 nd semester lecture course, Chem 322. Chemistry 321 covers the first half of McMurry s Organic Chemistry, either 5 th or 6 th Edition. The students taking the course major mostly in chemistry, biochemistry, or biology (pre-med). The exams in this book are typical of those given in sophomore organic at smaller universities. At many larger universities the exams are made up of multiple choice questions, whereas this course requires written responses from the student. [One exception to this pattern is the University of Michigan organic chemistry taught by Brian Coppola and colleagues.] The chapters and chapter topics covered by each quiz and exam are included in the Table of Contents. (The 5 th & 6 th Editions of McMurry are very similar in chapter organization.) Typical questions are of the following type: -Given the name, write the structural formula -Given the structural formula, write the IUPAC name -Predict the major product, given starting material and rxn conditions. -Suggest a several-step laboratory synthesis for a given compound -Predict, and justify, the order of reactivity toward certain reaction conditions -Guess the structure given NMR and IR spectra -Predict, and explain your prediction, which acid is stronger. Studying with these exams In a departure from previous editions, this book does not include answers. You as an organic student should formulate your own answer key after you have attempted the quiz or exam. The following quote is from Brian Coppola of the University of Michigan regarding the use of their "coursepack" of old exams. Organic chemistry (and, just to editorialize a bit, any respectable university course) asks you to learn AND apply the ideas... That is why using the coursepack of old exams has to be approached thoughtfully: those facts will not be on your tests... but the processes will be. Those pages are the actual exam pages. The students who took those exams did not have an answer key. Those exams are the chance to PRACTICE the process without the safety net of an answer key. If you wish to maximize your exam performance in this course, first study the assigned problems and be able to do them independently of the text; second, use this book; third, read Conquering Test Anxiety by Fiore and Pescar, or Aceing College by alberstram. iii

6 Useful data, equations, constants, and conversion factors K (temperature in Kelvins) = ºC ΔG o = Δ o TΔS o R (gas constant) = J/K-mol = cal/k-mol h (Planck s constant)= 6.62 x J-sec c (speed of light in vacuum)= 3.00 x 10 8 m/sec 1 micrometer = 10-6 m strain of one -Y 1,3- Y diaxial interaction (kj/mol) -F 0.6 -Cl 1.0 -Br 1.0 -O C C( ) C( ) C K eq = e ε = h ν = [ α ] p D ΔG RT hc λ = α l c = pk + log a o [ A ] [ A ] iv

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8 Chem 321 Name Quiz 1, Chap 1&2 McMurry 5th Ed 15 Sept For EAC of the molecules displayed on the screen: Draw a correct line-bond formula (Lewis) formula showing single and double bonds, and non-bonding pairs. If different resonance forms are possible, just show only ONE. (12 pts) 2. Considering BOT molecules in question 1: (9 pts) (A) ow many sp 3 -hybridized carbons are there? Put the number inside this box: (B) ow many sp 2 hybridized carbons are there? Put the number inside this box: (C) ow many sp hybridized carbons are there? Put the number inside this box: 3. Draw the resonance forms of an anion (C 4 4 NO 2 - ) with the following connection map: (9 pts) O C C N O C C 1

9 Chemistry 321 Name Quiz 2, Chap 3,4 McMurry 5th Ed, Alkanes and Cycloalkanes 22 September 2000 PLEASE ALSO PUT YOUR NAME ON TE BACK AT TE TOP RIGT. SET. YOU MAY USE A MODEL 1. Provide correct IUPAC names for each of the following compounds. (The arrow relates to Q2) (10 pts) 3 C 3 C 3 C C3 3 C 2. Using a Newman projection, illustrate ONE eclipsed conformation of the C-C bond indicated by the arrow in Q1. (4 pts) 3. Referring to the following molecule, fill in the correct numbers in the boxes provides: (8 pts) Number of equatorial hydrogens (on the ring C's)... Number of axial hydrogens (on the ring C's)... Number of 1,3-diaxial hydrogen-methyl interactions... Number of gauche methyl-methyl interactions Draw the ring-flipped chair conformation of the molecule shown in Q3 above. Indicate which conformation, the one shown in Q3 or the one in Q4, is more stable. Tell specifically why one is more stable than the other. (8 pts) 2