Chem 30B
Lab Exper. S 1
Models of Isomers
Check out a model kit and examine it closely. Single bonds are usually made with the
straight gray sticks. The short white sticks can be used for bonds to hydrogen. The
curved gray sticks will be used later for double and triple bonds.
You may want to work in pairs on this exercise, however each student must submit their
own report. Put all answers on the S1 Report form.
1) Make a model of methane, CH4 (structure 1).
2) Convert methane to methyl chloride, CH3Cl (structure 2) by replacing one of the
hydrogen atoms to a chlorine atom.
a) Did it matter which of the four hydrogen atoms were replaced with the chlorine
atom? In other words, could you have replaced any of the four hydrogen atoms of
methane and ended up with the same result? If so, all of the hydrogen atoms of
methane are equivalent.
b) Are the three hydrogen atoms in methyl chloride equivalent?
3) Convert your model of methyl chloride into dichloromethane, CH2Cl2 (structure 3).
a) Did it matter which of the three hydrogens in methyl chloride you replaced with a
chorine atom?
b) Are the two hydrogen atoms in CH2Cl2 equivalent?
4) Make a model of ethane, C2H6 or CH3CH3 (structure 4).
a) Are the six hydrogens equivalent? (Remember, we test for equivalent atoms by
thinking about replacement.)
5) Convert ethane to ethyl chloride, also called chloroethane, C2H5Cl or CH3CH2Cl
(structure 5).
a) Are the five hydrogens of ethyl chloride equivalent?
6) There are two compounds that are dichloroethanes, C2H4Cl2. Compounds with the
same molecular formula but different structures are called isomers. Isomers have the
same number of atoms of each element but these atoms are joined together in a
different manner. Differences in appearance due to rotation around single bonds do
not count. Make models of both isomers (structure 6 and structure 7).
a) Describe as clearly as possible the difference between the two.
b) Draw condensed and expanded structural formulas for both.
7) Make a model of propane, C3H8 (structure 8).
a) Does propane have an isomer? If so, draw it.
8) Convert propane to chloropropane, C3H7Cl (structure 9).
a) Make a second model of C3H7Cl (structure 10) that is an isomer of structure 9.
b) Describe the difference between the two structure 9 and structure 10.
c) Is a third isomer of C3H7Cl possible? If so, draw it.
9) Butane is C4H10
a) Make a model for the two possible butane isomers (structure 11 and structure 12).
10) Using your models from the previous question determine the number of isomers with
the formula C4H9Cl (structure 13a, 13b, 13c, 13d, etc.)
a) Draw clear structural formulas for all of them.
Name(s)
Date
Structure 1
please print
Section
Answers to Questions
Name
Structure 2
Answers to Questions
Name
Structure 3
Answers to Questions
Name
Structure 4
Name
Answers to Questions
Laboratory
Report S1
Name(s)
Date
Structure 5
please print
Section
Answers to Questions
Name
Structure 6
Answers to Questions
Name
Structure 7
Answers to Questions
Name
Structure 8
Name
Answers to Questions
Laboratory
Report S1
Name(s)
Date
Structure 9
please print
Section
Answers to Questions
Name
Structure 10
Answers to Questions
Name
Structure 11
Answers to Questions
Name
Structure 12
Name
Answers to Questions
Laboratory
Report S1
Name(s)
Date
Structure 13a
please print
Section
Answers to Questions
Name
Structure 13b
Answers to Questions
Name
Structure 13c
Answers to Questions
Name
Structure 13d
Name
Answers to Questions
Laboratory
Report S1