Exam 1

CH 130

April, 1998

Circle your name if you want to pick up graded exam personally

There are three pages and eleven questions on this exam. Be sure you have them all.

1. Describe or define precisely (and give an example)

Decolorization of Br₂-water by an alkene (4 points)

Titration (3 points)

Cracking of hydrocarbons (3 points)

2.

a. Draw chair and boat cyclohexane. Are these conformers or isomers of each other?

(5 points)

b. Explain clearly the distinction between conformer and isomer.

(5 points)

3. Circle each of the functional groups in the molecules shown below, and identify by name at least two of them.

(structures not shown on the web; look at the copy in the glass case)

(10 points)

4. Draw the isomers of C₅H₁₂ and give the IUPAC name of each isomer.

(10 points)

5. How many different mono-substituted isomers would result from the reaction of the molecule CH₃CH(CH₃)CH₂F with chlorine (one Cl per molecule)? Draw each of them.

(10 points)

6. Draw the structure of 4-ethyl-2-methyl-3-hexene.

(5 points)

7. Describe the general "molecular" structures of each of the allotropes of carbon: graphite, diamond, and C₆₀. Why do graphite and diamond have such different physical properties?

(5 points)

8. Compare the expected boiling points of the following three compounds (mark one "lowest bp" and one "highest bp). Name each of these three molecules.

CH₃CH₂CH₂OH

CH₃OCH₃

CH₃CH₂OH

(6 points)

Explain why the boiling points follow the trend you predicted.

(4 points)

9. The following questions refer to the laboratory experiment on 60 mg a Day.

(a) Describe why you performed the standardization of the DCP in the first part of the experiment.

 

(5 points)

(b) Suppose 2 drops of standard vitamin-C solution requires 6 drops of DCP and 2 drops of lemon juice requires 13 drops of DCP. If the standard vitamin-C is 0.75 mg/mL, what is the concentration of vitamin-C in the lemon juice in mg/mL?

 

(5 points)

10.

a. Draw five organic compounds with the molecular formula C₄H₈. Hint: consider cyclic structures as well as non-cyclic, and don't ignore cis-trans forms.

(10 points)

b. Circle which of the molecules in 10a. would be expected to decolorize Br₂-water and write the balanced chemical reaction for ONE such case, showing clearly the structures involved.

(3 points)

11. Shown below is a candidate for polymerization. What polymer might be produced from this monomer? Draw enough of the polymer to illustrate your answer.

CHCl=C(CH₃)CH₃

(7 points)