代写CHMB42H3 Summer 2024 PRACTICE FINAL EXAM调试数据库编程

日期：2024-08-13 07:14

CHMB42H3 Summer 2024

PRACTICE FINAL EXAM

Part I – Lab Related Material – 25 points

For the following multiple choice questions, please circle your final answers in the table below.

Answers selected on the written questions will NOT be marked.

1. Which of the following methods were not used to assess the purity and identity of experimental products during the semester? (2 pts)

a. Melting point values and ranges

b. Thin layer chromatography

c. Gas chromatography mass spectrometry

d. Ion coupled chromatography

2. What is a chemical used this semester that is a suspected carcinogen? (2 pts)

a. Acetic acid

b. Dichloromethane

c. Magnesium sulfate

d. Sodium borohydride

3. Which of the following is NOT a highly flammable chemical used this semester? (2 pts)

a. Diethyl ether

b. Ethanol

c. Ethyl acetate

d. Sulfuric acid

4. Which physical property helps you determine which layer is on the top or the bottom during a liquid-liquid separation/extraction? (2 pts)

a. Solubility

b. Boiling point

c. Density

d. Partition coefficient

5. How many principles of Green Chemistry are there? (2 pts)

a. 10

b. 11

c. 12

d. 13

6. Express the Rf of compound X as a fraction using the appropriate letters from the arrows below. (1 pts)

7. During recrystallization of your products, often times you should have had a colourless solution once all of the solids had dissolved. If, by chance, you had a coloured solution, what would you have had to add and do? (2 pts)

8. During lab 2 (FC alkylation), ethanol was used as your recrystallization solvent to dissolve your product. However, ethanol was also used during suction filtration to wash and isolate the crude product. Briefly explain how this is possible. (3 pts)

9. Green Chemistry is a growing sector of interest aiming towards more sustainable chemical practices. Name one of the twelve principles. Also, name one of the three green metrics and briefly explain the purpose/necessity of green metrics. (4 pts)

10. For your lab 2 and 5 products, FT-IR spectra were obtained for your products. How would IR spectroscopy have been useful to determine whether your lab 1 and 3 reactions were complete and/or worked up appropriately? Give the functional group(s), approximate IR region, and reason with your explanation. (5 pts)

Part II – Midterm Material – 45 points

For the following multiple choice questions, please circle your final answers in the table below.

Answers selected on the written questions will NOT be marked.

11. How many of the following molecules can exist as conjugated systems of 5 overlapping p orbitals?

a. 0

b. 1

c. 2

d. 3

12. How many atoms are part of the conjugated system of the molecule shown below?

a. 7

b. 6

c. 11

d. 13

13. How many atoms are part of the conjugated system of (+)-Frondonsin B shown below?

a. 5

b. 8

c. 10

d. 12

14. Which of the following compounds would liberate the most heat when hydrogenated and why?

a. A because it’s conjugated.

b. A because it’s not conjugated.

c. B because it’s conjugated.

d. B because it’s not conjugated.

15. Which of the following molecules can exist as aromatic upon the loss of a proton (H+)?

a. A and B

b. A and D

c. C and D

d. B and C

16. Which molecule will react faster with Br2 in the presence of iron bromide and why?

a. A because the amino group makes the ring more negative through charge delocalization.

b. B because the nitro group makes the ring more negative through charge delocalization.

c. A because the amino group makes the ring less negative through charge delocalization.

d. B because the nitro group makes the ring less negative through charge delocalization.

17. Which of the following is NOT a correct mechanistic step in the following Friedel-Crafts alkylation?

18. Which of the following best describes the two molecules shown below?

a. A is more reactive to SEAr than B and is meta. directing.

b. A is less reactive to SEAr than B and is meta. directing.

c. A is more reactive to SEAr than B and is ortho/para directing.

d. A is less reactive to SEAr than B and is ortho/para directing.

19. Which ordering of steps would more efficiently produce the product shown below?

a. 1 → 3 → 2

b. 1 → 2 → 3

c. 3 → 2 → 1

d. 2 → 3 → 1

20. Which of the following molecules would react quickest via an electrophilic aromatic substitution process?

21. Which of the following best describes the Hofmann product in an elimination reaction?

a. An unhindered base giving the less substituted product.

b. An unhindered base giving the more substituted product.

c. A hindered base giving the less substituted product.

d. A hindered base giving the more substituted product.

22. Which cyclohexane derivative would you expect to react faster under E2 elimination conditions and why?

a. A because it’s less sterically hindered.

b. B because it’s less sterically hindered.

c. A because its β-hydrogen is antiperiplanar to the leaving group.

d. B because its β-hydrogen is antiperiplanar to the leaving group.

23. Which of the following represents the first mechanistic step in the oxidation reaction shown below?

24. Which of the following mechanisms are promoted by polar protic solvents?

a. SN1 and SN2

b. E1 and E2

c. SN2 and E2

d. SN1 and E1

25. Which of the following reaction mechanisms would you expect to dominate given the reaction and conditions shown below?

a. SN1

b. SN2

c. E1

d. E2

26. Complete the missing products and reagents. (15 pts – 1 pt/reagent, 2 pts/structure)

Part III – Post-Midterm Material – 85 points (Note midterm material may be relevant!)

27. Consider the reaction below:

a. What is the name of the reaction taking place? (1 pt)

b. How could you use IR spectroscopy to determine whether the following reaction had occurred? (2 pts)

c. After purifying the product, how could you determine whether all the NH2NH2 had been removed? (2 pts)

28. What hydrocarbons (CxHy) containing a six-membered ring will have a molecular ion peak at m/z = 112? Do not include stereoisomers. (8 pts)

29. Identify the following compound C7HxO from its mass spectrum, IR spectrum, and 1H NMR spectrum. Show spectral analysis for full marks. (10 pts)

30. Using an alcohol for one method and an alkyl halide for the other, show two ways to make each of the following esters (you may need more than 1 step): (8 pts)

a. Propyl acetate (odour of pears)

b. Ethyl butyrate (odour of pineapple)

31. Circle the reaction(s) that do(es) NOT give the carbonyl product shown. Draw a box around the reaction(s) that do(es) not occur that can be made to occur if an acid catalyst is added to the reaction mixture. (5 pts)

32. Propose a mechanism for each of the following reactions:

a. (8 pts)

b. (4 pts)

33. Complete the missing reagents or products. (14 pts – 1 pt/reagent, 2pts/structure)

34. Suggest reactants and a reaction pathway to synthesize the following compounds from an ester-containing compound. Show retrosynthetic analysis for full marks. You do NOT need to show the mechanism. (6 pts)

35. Show how the following compound can be prepared from the given starting material. Show all intermediate products from each step. You do NOT need to show the mechanism. (6 pts)

36. Identify the following chemical structures. (Hint: A shows 3 singlets in its 1 H NMR spectrum with integral ratios of 3:2:3 and gives a positive iodoform. test). (11 pts)