EXPERIMENT 11

[models.lab]

OBJECTIVES:

1. To improve your knowledge of organic compounds.

2. To be able to construct models of simple organic compounds.

3. To be able to transfer model structure to diagrams on paper.

4. To be able to build and diagram isomers of simple organic compounds.

DISCUSSION:

You will each be given a molecular model building kit. Each colored ball represents an element. Using the kit, you will make three-dimensional models of some organic compounds and from these models, you will draw their structural formulas.

The holes in the balls represent available electrons and those MUST be used up when joining balls. Wooden pegs are used for single bonds (2 shared electrons), while springs are used for double and triple bonds (4 and 6 shared electrons, respectively).

The following prefixes show the number of carbon atoms in the compound or group:

1= meth- 4= but- 7= hept- 10= dec-

2= eth- 5= pent- 8= oct- ...etc...

3= prop- 6= hex- 9= non- 100= cent-

Alkanes have only single bonds and have the formula C_nH_2n+2. Thus, CENTANE would have the formula C₁₀₀H₂₀₂. Alkenes have a double bond and alkynes have a triple bond.

EXPERIMENTAL PROCEDURE: (Get the instructor's approval at each XX.)

1. Make a model of these saturated hydrocarbons. Write their structural formulas.

a. ETHANE ( C₂H₆ ) b. BUTANE ( C₄H_? )

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2. a. Make a model of PROPANE, a saturated hydrocarbon with 3 carbons.

Write its structural formula.

b. Write its molecular formula: ______________

3. a. Make a model of PROPENE. This is an unsaturated hydrocarbon with one double bond and 3 carbons. Write its structural formula.

b. Write its molecular formula: ______________

4. a. Make a model of a hydrocarbon with 4 carbons and one TRIPLE BOND. Write its structural formula. You have an isomer of BUTYNE. Is it 1-BUTYNE or 2-BUTYNE?

name _______________

b. Write the structural formula of the other isomer of butyne.

XX

name _______________

c. Write their molecular formula: ______________

d. Can you invent a third isomer?

5. Write the structural formulas for all 5 of the isomers of HEXANE. This compound has 6 carbons and is saturated. You can omit the H atoms. [A] is the "normal" formula.

[A] C - C - C - C - C - C C - C - C - C - C

|

C NOT an isomer.

Same as [A]

6. Prepare a model of BENZENE, C₆H₆. This is a ring or "aromatic" compound. It has 3 double bonds. The double bonds alternate with single bonds. Write its structural formula.

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7. a. Write the structural formula for 3-METHYLPENTANE.

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b. Write its molecular formula: ______________

c. Give the structural formula and the name of ONE other isomer having the same formula as (b). What is its name?

8. a. Write the structural formula for 2,2,4-TRIMETHYLPENTANE.

XX

b. What is its molecular formula?

c. Give the structural formula and the name of TWO other isomers having

the same formula as (b).

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EXP # 11 - QUESTIONS Name _______________________ Sec ____

[ After you complete the lab, an "exit quiz" will be given. It will look like this but with the XXXX filled in.]

1. Which of the following is the molecular formula of XXXXXX ?

2. Which of the above is the structural formula of XXXXXX ?

3. Write the structural formula of XXXXXX.

4. Are the following two compounds isomers? (yes or no)

5. Write the structural formula for XXXXXX.