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2423 Lab Final study guide 2014
Part 1 70% of the exam will be multiple choice (15 questions)
1. Do Alkanes react with bromine in the dark?
a. Alkanes never react with bromine in the dark
c. some alkanes do not react at all
b. some alkanes react slowly
d. both b and c
e. None of the above
2. Why should we be extremely careful when using potassium permanganate?
a. it is a weak oxidizing agent
d. it will sting your skin
b. it is a strong oxidizing agent
c. it will leave your skin very smooth
e. both b and d
3. What do you obtain when you react alkenes and bromine together?
a. unsaturated hydrocarbons
b. alcohols
c. saturated hydrocarbons d. halogen compounds
4. What is the Baeyer’s test used for?
a. for saturation b. unsaturation c. triple bonds
d. double bonds
e. none of the above
5. What happens when you react bromine and toluene?
a. nothing
b. benzyl bromide
c. benzene
d. both b and c
e. none of the above
6. Which one is more stable the cis-form or the trans- form?
a. equally stable
b. the cis- form
c. the trans- form
d. neither
7. Do Malic Acid and Fumaric Acid have the same physical properties?
a. Yes
b. no
c. same chemical properties and same physical properties
d. different chemical properties and same physical properties
e. none of the above
8. Butene-1,2-dioic exist both as cis- and trans- forms. Give the name for both the cis- form and the trans- form.
a. cis isomer –malic acid
b. cis isomer- butanoic acid
c. trans isomer- fumaric acid d. both b and c e. both a and c
9. A factor that is important in selecting a suitable solvent for crystallization is:
a. The solvent should dissolve large quantities at low temperatures.
b. The solvent should dissolve mechanical impurities.
c. The solvent should react with the substance being purified.
d. It is readily removed from the purified product.
10. It is important to pack a melting point tube densely because
a. It will enable the melting point tube to “stick” to the thermometer.
b. The powder will fall out of the melting point tube.
c. The temperature range for melting will be large.
d. It will ensure rapid transfer of heat through the sample.
11. When washing your recrystallized crystals the best thing to do is
a. Use suction filtration and a Buchner funnel.
b. Heat the crystals in the appropriate solvent.
c. Both a and d.
d. Wash the crystals with cold solvent.
12. Which is a step in distillation?
a. Condensing the vapor.
b. Collecting the vapor.
c. Boiling the condensate.
d. All of the above.
13. Tertiary haloalkanes undergo which mechanism for the formation of alcohols?
a. SN3
b. “backside attack”
c. SN1
d. SN2
14. In the hydrolysis of tert-butyl chloride the rate of reaction depends on the concentration of which component?
a. Carbocation
b. Oxonium ion
c. Nucleophile
d. Alcohol
15. The E1 mechanism involves which of the following?
a. A one step concerted reaction with out formation of a carbocation
b. A two step process with formation of a carbocation
c. A three step process with formation of a carbocation
d. A four step process with out formation of a carbocation
Part II (No partial credit will be given)
30% will not be multiple choice (5 questions, 4 worth 5 pts and 1 worth 10 points)
16. (4 pts) In the reaction to form tert-butyl alcohol, Dr. Delgado obtained 2 g of tert-butyl alcohol. Her theoretical yield
was calculated to be 3.5 g. What was the % yield?
17. (4 pts) Compound X is an unknown substance and can either be one of two known substances, A or B.
Describe(briefly and as simple as possible) a good method to determine what X is
18.(4 pts) Can we use the procedure of isomerization used in question 8 for the preparation of other cis- to transisomers? Explain.
19. (4 pts)Explain E1 mechanism (briefly and as simple as possible)
20. (4 pts)Explain SN2 mechanism (briefly and as simple as possible)
21. (10 pts)The reaction of ethanol with (S)-2-BROMOPENTANE follows via SN1. Write the mechanism of this reaction.
Include mechanism arrows, labels for each species, and the rate determining step (slowest step). Explain in your own
words what is happening.