Binghamton University - CHEM 231 Chem 231 Fall 08 Exam 1)Which is the strongest base?   2

Binghamton University - CHEM 231

Chem 231 Fall 08 Exam

1)Which is the strongest base?

2. Propyne is a much better acid than propane.  This is because of the differences in hybridization of the carbons.  Based on the statements above, which of the following is most likely to be true?

a. sp hybridized carbons are more electronegative than sp³ hybridized carbons.

b. sp³ hybridized carbons are more electronegative than sp hybridized carbons.

3. In cyclohexane there is

a. less angle strain than in cyclobutane

b. fewer eclipsed bonds than in cyclopropane

c. 2 different types of hydrogens

d. Choices a, b and c are correct.

e. Choices a and c are correct, but choice b is incorrect.

4. At equilibrium the reaction below lies mostly to the left.

a. True

b. False

5. Which list is in order from least stable to most stable?

a. t, u, v

b. u, v, t

c. v, t, u

d. u, t, v

e. v, u t

6. Which list is in order from least stable to most stable?

7.  Draw the compounds listed.

a. 4,4-dipropylheptane

b. 3-isopropyl-2,4-dimethylpentane

c. cis-1-ethyl-3-methylcyclopentane

8. Name each of the following compounds.

9. Show the formal charges or just the charge for each of the following 3 examples.

10.  Show all isomers of C₃H₆F₂.

11. Draw the following in their lowest energy stereoisomer for a-c.

a. 1, 2 diethylcyclobutane; b.1,2,3 trimethylcyclopropane; c. 1,2,3,4-tetramethylcyclobutane

12. Draw the lowest energy conformation of trans- 1,3-dimethyl cyclohexane

13. Name the bicyclic compound below.

14. For the 2 equations below draw proper arrow pushing on the starting material, to give the resonance structure or product shown.

15 For each of the following indicated atom what is the hybridization?

16. Ammonia can be considered

a. a Lewis acid

b. a Bronsted-Lowry Acid

c. a Lewis base

d. a and b are the only correct choices

17. A double bond is stronger than a single bond.

b. False.

18. Acetylene

a. has a triple bond and has 120° bond angles at carbon

c. has a double bond and has 120° bond angles at carbon

d. has a double bond and has 180° bond angles at carbon

19. Which is the most stable of the following compounds?
 

20. Which list is in the correct order from weakest to strongest acid?

21. The carbons of ethylene, the simplest alkene, are bonded together by

a. 2 pi bonds

b. 2 sigma bonds

22. A compound with a generic structural formula C_nH_2n can be

a. an alkane

b. an alkene

c. a cycloalkane

d. Choices a and c are correct.

e. Choices b and c are correct.

23. The carbon and the nitrogen in HCN share ___ bonds made up of the following types of shared orbitals.

a. 3; 4sp and 2 p

b. 2; 2sp and 2p

c. 3; 2sp and 4p

d. 3; 4sp² and 2p

e. 2; 2sp² and 2p

24. Electronically, CH₃⁺ would be most similar to ________; therefore the carbon is _______hybridized.

a. NH₃; sp²

b. NH₃; sp³

c. BH₃; sp³

d. BH₃; sp²

e. OH₃⁺; sp³

25. Select the list that shows the 3 compounds from weakest to strongest base.

26. The compound below has a formal charge of _____on the nitrogen and a formal charge of _____ on the oxygen and the charge on the compound is _______.

a. –1; 0; -1

b. 0; -1; -2

c. +1; 0; +1

e. None of the choices a-d is correct.

27. Propyne is a much better acid than propane.  This is because of the differences in hybridization of the carbons.  Based on the statements above, which of the following is most likely to be true?

a. sp hybridized carbons are more electronegative than sp³ hybridized carbons.

b. sp³ hybridized carbons are more electronegative than sp hybridized carbons.

28. Show a resonance contributor for each of the following compounds.(15)

30. Which lists the compounds from weakest to strongest base?

31. Consider 1-chloropropane, shown below.  Looking down the C₁-C₂ axis sketch the highest and lowest energy conformations using a Newman projection.( in your drawing make C₁ in front.) Are there any other unique conformations available to this molecule? (circle correct answer)(15)

32a. Draw the compound C₂H₄. b. Indicate the hybridization of carbon; c. Indicate the HCH bond angles.

33. Indicate the kind of bicyclic compound each of the following are.(12)

34. Describe the shape of the following molecules (select from trigonal pyramidal, tetrahedral; trigonal planar, linear, bent).(12)

a. BH₃; b. NH₃; c. NH₄⁺; d. NH₂^-