Linda Waldman Chemistry 211 F' (20 points) Multiple Choice. Please write your answers in the spaces provided on the right.

Transcription

1 Exam1 1) There are a total of 13 questions 2) Counting this cover sheet, there are a total of 7 pages- check to ensure you have all 7. 3) All 7 pages must be turned in for grading. 4) Use the backside of preceding pages for scratch paper. 8) Any cheating will result in the dismissal from class with an "F" grade. 9) Please put your name or initial on each page 10) You must sign below to receive a grade on this exam. I have read and understand the above instructions for this exam. Signature

2 1. (20 points) Multiple Choice. Please write your answers in the spaces provided on the right. a. In quantum mechanics a node (nodal surface or plane) is: 1a A) a place where Ψ is negative. B) a place where Ψ is positive. C) a place where Ψ = 0. D) a place where Ψ 2 is large. E) a place where Ψ 2 is negative. b. Which principle(s) or rule(s) must be used to determine the correct electronic configuration for carbon in its ground state: 1b A) Aufbau Principle. B) und s Rule. C) Pauli s Exclusion Principle. D) A and B only. E) All three. c. ow many 2p atomic orbitals from boron must be mixed with a 2s atomic orbital to yield the bonding hybrid atomic orbitals in BF 3? A) 1 B) 2 C) 3 D) 4 E) 5 1c d. What shape does the methyl cation, C 3 +, have? 1d A) ctahedral B) Tetrahedral C) Trigonal planar D) Linear E) Trigonal pyramidal e. The electron configuration, 1s 2sp3 2sp 3 2sp 3 2sp 3 represents: A) the ground state of boron. 1e B) the sp 3 hybridized state of carbon. *C) the sp 3 hybridized state of nitrogen. D) the ground state of carbon. E) an excited state of carbon. f. Which of the following is a set of constitutional isomers? 1f Br C 3 C 3 CC 2 Br C 2 Br C 3 CC 2 C 3 C 3 C 3 C C 2 Br C 3 I II III IV A) I and II B) II and III C) I, II and III D) II, III and IV *E) I, III and IV

3 g. Which of these would you expect to have the lowest boiling point? 1g A) C 3 C 2 C 2 B) C 3 CC 3 *C) C 3 C 2 C 3 D) C 3 C 2 C 2 C 2 E) C 3 C 2 C 2 C 3 h. Drawn below is atropine. C 3 N C 2 C 6 5 Which of the following functional groups is NT in atropine? 1h A) Amine B) Ester C) Alcohol D) Benzene ring *E) Ketone i. Which formula represents a compound that is different from all the rest? C2 Cl ClC2C2C()2 CC2C2Cl Cl I II III IV A) I B) II C) III *D) IV E) None of these 1i j. This alkane is predicted to have the highest melting point of those shown: A) C2C2 B) C2C2C2 C) C D) C E) CC2 1j 2. (5 points) Circle the following compound(s) which would be expected to have a dipole moment. A) C 4 B) C 2 Cl 2 C) CCl 3 D) N 3 E) BF 3

4 3. (4 points) Circle the structure(s) below in which the oxygen has a formal charge of +1: C A) B) C) D) 4. (5 points) Circle the following chemical(s) which would have a trigonal planar (triangular) structure: :C 3 - C 3 + :N 3 BF 3 : 3 + A) B) C) D) E) 5. (4 points) Briefly define or explain the steric effect. 6. (6 points) Briefly explain the difference in stability between cyclopropane, cyclobutane and cyclopentane.

5 7. (3 points) What does the eisenberg uncertainty principle tell us about an electron? 8. (10 points) Draw the most stable conformer of the following, show all of the attached hydrogens, and indicate whether each alkyl substituent is axial or equatorial. a) cis-1,3-dimethyl cyclohexane b) trans-1-ethyl-2-methyl cyclohexane 9. (8 points) Provide the correct IUPAC name for the following compounds. a)

6 b) 10. (8 points) a) Draw a Newman structure of the gauche conformer of 4-methyldecane looking down the C 5 C 6 bond. Do not use R to indicate the alkyl chains. b) What is the dihedral angle between the two longest groups on C 5 and C 6 in your structure? 11. (5 points) Draw the sp 2 hybrid orbital made from the following s and p orbitals:

7 ...P...S 12. (10 points) For each of the indicated atoms below, a) identify the hybrid atomic orbital and b) indicate the oxidation number. a N 2 d b Cl c e Carbon atom a b c d e Atomic orbital xidation number 13. (12 points) Draw the resonance structures for the following: a) + b) C 3 N _

8 c) C _