Chemistry 201. MW 12pm 1:15pm Examination #1 July 22 nd Bronco ID. Question Score Possible Points. 1 (10pts) 2 (24pts) 3 (14pts) 4...

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1 Chemistry 201 MW 12pm 1:15pm Examination #1 July 22 nd 2015 Name Bronco ID. Question Score Possible Points 1 (10pts) 2 (24pts) 3 (14pts) 4... (22pts) 5 (30pts). Total (100pts) 1. Read each question carefully. Make sure you are answering the question which is being asked. Write your answer clearly and do not use notation such as to show your answer 2. Answer easier questions first, more difficult questions later 3. Ask the instructor for clarification if you are puzzled by the question 4. Show work for credit. Use dimensional analysis by meant of using an appropriate stiochiometry to prove your solution. Watch for significant figures. 5. Any forms of cheating will be an automatic F 6. The instructor can t read students mind so DO NOT MAKE ANY ASSUMPTIONS 7. GOOD LUCK 1

2 Question I (10pts): Multiple choices - choose one best answer 1. Which of the following statements about carbon is false? Carbon A. compounds have covalent bonds B. compounds can have multiple bonds C. is tetravalent D. uses sp 2 hybrids to form tetrahedral structures 2. Another term for alkanes is A. Alkenes B. alkynes C. saturated hydrocarbons D. unsaturated hydrocarbons 3. Compounds that have the same formula but different molecular structures are called A. isoelectronic B. isomers C. isotones D. isotopes 3. What is the hybridization of the indicated carbon with the asterisk in the following molecule? A. sp B. sp 2 C. sp 3 D. sp 3 d 4. Which of the following does not contain a carbonyl group? A. an alcohol B. an alcohol C. an amide D. an ester 5. Which statement below is false concerning nomenclature rules for alkanes? A. Carbon atoms are numbered starting with the atom farthest from the branching point B. Each branching group is assigned a number referring to its point of attachment in the parent chain C. The name of the alkane is written as a single word D. The parent name is taken from the longest continuous chain of carbon atoms 2

3 6. Which sequence correctly ranks the indicated protons in order of increasing acidity? A. 1 < 2 < 3 B. 2 < 3 < 1 C. 2 < 1 < 3 D. 1 < 3 < 2 7. Which of the following is not a conjugate acid-base pair (in that order)? A. H 3PO 4, H 2PO - 4 B. HBF 4, - BF 4 C. CH 3CH 2OH, CH 3CH 2O - D. H 3O +, H 2O E. HPO 4-, H 2PO A molecule of NH 3 has a.geometry and a molecular dipole moment that is A. tetrahedral, zero B. bent, nonzero C. trigonal planar, zero D. trigonal pyramidal, nonzero 9. Rank these molecules or compound according to their boiling point, starting from the highest Heptanes, 3-hexanol, n-hexylamine, 2-pentanol I II III IV A. I > II > III > IV B. IV > III > II > I C. II > III > IV > I D. III > II > IV > I 10. Which of these is the weakest of the intermolecular attractive forces? A. ion-ion B. dispersion forces C. dipole-dipole D. covalent bonding E. hydrogen bond 3

4 Question II (24pts) 1. (14pts) For the following reaction a. Predict the products expected for the Bronsted-Lowry acid/base reaction: b. In the boxes provided, label each of the above products. (e.g., acid, base, conj. acid, conj. base) c. Use curved arrows to show the reaction mechanism. d. To which side does the equilibrium lie (R/forward or L/reverse)? Explain in detail to support your answer 2. (10pts) The initial product of the reaction between (CH 3) 3C + and CH 3OH is given in the following chemical reaction. Using curve arrows to show how it make then identify the Lewis acid and Lewis base 4

5 Question III (14pts) 1. (8pts) Fill in the missing electrons and draw one more resonance this structure, using an arrow to show the movement of electrons then label the major and minor contributors and state your reason. 3. (6pts) Explain why one of these anions is much more stable than the other 5

6 Question IV(22pts) 1. (8pts) Using bond-line to draw the following molecules a. sec-butyl alcohol b. 1-isopropyl-3-ethylcyclopentane 4. (8pts) Give a systematic name (IUPAC) for each of the following molecule. Don t forget to prove geometric isomer cis or trans when applicable. a. b. b. (4pts) 2. (6pts) Draw all the isomers with the following formula. The total number for each is gen in parentheses. (Use bond-line drawing) Three secondary (2 o ) amines with the molecular C 4H 11N 6

7 Question V: (30pts) 1. (8pts) Draw a conformation and its ring flip then explain which conformation is better. COOH is more energetic than OH (18pts) Looking down from the indicated direction, draw all Newman projections by rotating around the C2-C3 for the molecule below and rank them on the energy diagram. OH is more energetic than an alkyl group 7

8 *Use this space to draw the energy diagram Bonus: (5pts) Show hydrogen bonding between the following molecules Methanol and water A methylamine and water. B a. Identify H-bond acceptor and H-bond donor b. Which H-bond is stronger (A or B)? Explain 8

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Chemistry 201. MW 12pm 1:15pm Examination #1 July 20 th Bronco ID. Question Score Possible Points. 1 (17pts) 2 (28pts) 3 (14pts) 4...

Chemistry 201. MW 12pm 1:15pm Examination #1 July 20 th Bronco ID. Question Score Possible Points. 1 (17pts) 2 (28pts) 3 (14pts) 4... Chemistry 201 MW 12pm 1:15pm Examination #1 July 20 th 2016 Name Bronco ID. Question Score Possible Points 1 (17pts) 2 (28pts) 3 (14pts) 4... (22pts) 5 (19pts). Total (100pts) 1. Read each question carefully.