Name: ______________________________________
Homologs
Purpose: To create models of various organic molecules and compare.
Pre-Lab:
1. How many valence electrons does carbon have? _____ How many times does it bond? _____
2. How many valence electrons does oxygen have? _____ How many times can it bond? _____
3. How many valence electrons does hydrogen have? _____ How many times does it bond? _____
Procedure:

Part One: Single Bonds
1. Make a model of CH4 using the model kit.
2. Replace one hydrogen atom with a carbon atom and add additional hydrogen atoms until every bond
of each carbon atom is filled. Draw and name this molecule with reference to tables P and Q.
3. Repeat step two until you have created 5 molecules.
1
2
3
4

5
Part Two: Double Bonds
1. Make a model of C2H4 using the model kit.
2. Replace one hydrogen atom with a carbon atom and add additional hydrogen atoms until every bond
of each carbon atom is filled. Draw and name this molecule with reference to tables P and Q.
3. Repeat step two until you have created 5 molecules.
1
2
4
3
5

Part Three: Triple Bonds
1. Make a model of C2H2 using the model kit.
2. Replace one hydrogen atom with a carbon atom and add additional hydrogen atoms until every bond
of each carbon atom is filled. Draw and name this molecule with reference to tables P and Q.
3. Repeat step two until you have created 5 molecules.
1
2
4

3
5
Part Four: Functional Groups
1. Using your model kit construct the following molecules, draw them, name them and identify their
functional group (use table R).
C3H7OH
C4H9OH
CH3OC2H5
C3H7OCH3
C2H5CHO
C5H11CHO
CH3COC3H7
C2H5COC2H5
C2H5COOH
HCOOH
C2H5COOCH3
C6H13COOC2H5
Questions:
1. When constructing your first set of molecules, every time a carbon atom was added, how many
hydrogen atoms were added?
2. Does this first set of molecules represent a homologous series? Explain.
3. What do the name of the series and the name of the members in the first series have in common?
4. When constructing your second set of molecules, every time a carbon atom was added, how many
hydrogen atoms were added?
5. Does this second set of molecules represent a homologous series? Explain.
6. What do the name of the series and the name of the members in the second series have in common?
7. When constructing your third set of molecules, every time a carbon atom was added, how many
hydrogen atoms were added?
8. Does this third set of molecules represent a homologous series? Explain.
9. What do the name of the series and the name of the members in the third series have in common?
10. In part one, you created a molecule with only one carbon atom to start the series. Why didn’t the
second and third series start with only one carbon atom?