Chemistry 21: Determining the IUPAC rules for naming ORGANIC MOLECULES

Open up Netscape (NOT Internet Explorer)

Google search (images or web)

After selecting a molecule below, you can change the display by holding down the mouse key and choosing within the options palette (ex—under display, choose ball-and-stick, deselect rotation)

Draw the skeletal structure for the following molecules (ignore the H’s bonded to C). Don’t draw it 3-D.

Saturated Hydrocarbons / Structure / Saturated Hydrocarbons / Structure
Methane / 2-methyl butane
Ethane / 2-methyl pentane
Propane / 2-methyl octane
Butane / 4-methyl octane
Pentane / 2, 2-dimethyl hexane
Hexane / 2,3-dimethyl hexane
Heptane / 2, 3, 3-trimethyl heptane
Octane / 2, 2, 6-trimethyl heptane
Cyclopropane / Cyclohexane
4-ethyl-2-methylhexane / 1-methyl-4-propyl-cyclohexane
Cyclobutane / Cylcopentane
Unsaturated Hydrocarbons / Structure / Unsaturated Hydrocarbons / Structure
Ethene / Propyne
Ethyne / 2-methyl propene
Propene / Cyclobutadiene
Trans-2-Butene
(labeled as E) / Cis-2-pentene
Cis-2-butene
(labeled as Z) / Trans-2-pentene
1-pentene / cyclohexene
Alcohols / Structure / Alcohols / Structure
Methanol / 2-propanol
cylcohexanol / 1,2-ethandiol
1-propanol / 3-pentanol

Questions to answer in your notebook with full sentences.

1. Looking at the structures, what does “saturated” mean?

2. What do the following endings mean?

a. –aneb. –enec. –yned. –ol

3. How do you identify the number of carbons in the longest chain?

1:3:5: 7:

2:4:6:8:

4. a. When numbering the parent chain, do you want the branches to have the

highest or lowest numerical values?

b. Why is 1-ethyl ethane not the correct name?

5. What do you use when there are two of the same groups off the parent

chain? Three? Four?

6. When there is more than one type of branch off the longest chain, are they listed in any type of order in the name?

7. What do the numbers in front of the alkenes refer to (1-pentene vs 2)?

8. a. Do all Unsaturated hydrocarbons use the prefix cis and trans?

b. Which ones do?

c. How does each term describe the structure?

d. The cis and trans versions of a molecule are ______.

e. With 1-pentene you do not need a cis or trans. Why?

1. Working from the back of the name and moving forward, draw the skeletal structure for the following:

a. 2,2-dimethylbutaneb. 3-ethyl-3-heptene

c. 3-ethyl-2-methyl-1-hexened. 3-pentene (add H to C3 and C4 to

and draw both cis and trans forms)

e. 3,3-dimethyl-1-butynef. 4,4-dimethyl-2-pentyne

g. 4,4-dimethyl-2-octanolh. chlorocyclopentane

i. 1,3–difluoro–2–iodocyclohexanej. 3,4–dibromo–6–methyl–1–heptyne

k. 3–chlorocyclopentenel. 2,3–dichlorocyclobutene

2. Each of the following names are incorrect. Draw them as written and then give the correct name.

a. 2, 4, 5-trimethylhexane

Correct name: ______

b. 2-ethyl-2-propylbutane

Correct name: ______

c. 2-ethylhexane

Correct name: ______

d. 2-ethyl-4-methyl-3-propylhexane

Correct name: ______

e. 3-methyl-2-butene

Correct name: ______

f. 3-propanol

Correct name: ______

g. 2,2-dimethyl-3-butyne

Correct name: ______

h. 5-octyne

Correct name: ______

3. Draw (skeletal) and name the 3 unique isomers of C5H12 (1st: saturated or unsaturated?)

4. Draw and name the 4 isomers of C4H8 (1 saturated ring and 3 unsaturated chains)