Portage Learning CHEM 219 Principles of Organic Chemistry Module 8
Exam
Question 1
Complete the following statement regarding the classification of polymers by filling in the blanks:
Polymers are large ____ made by repetitive linking of smaller units known as monomers. The
terms polymers and monomers are derived from the _____ roots poly (many), mono (one), and
_____(part). Polymers are classified as macromolecules. A macromolecule is a very large
molecule composed of thousands of _____ bonded atoms. Polymers can also be classified as
either natural or _____. Natural polymers include rubber, carbohydrates like starch or cellulose,
proteins, and nucleic acid (DNA/RNA). The biologically relevant natural polymers are sometimes
called _____. Synthetic polymers are created by scientists in a lab (not formed in nature) for
specific purposes.
Answer
1. Molecules
2. Greek
3. Meros
4. Covalently
5. Synthetic
6. Biopolymers
Question 2
Describe the major difference in the formation of addition polymers versus condensation
polymers.
Answer
A defining characteristic of a chain-growth/addition polymer is that the final polymer retains all of
the atoms of the monomers. Step-growth polymers (also known as condensation polymers) are
formed by the reaction between two different functional groups on different monomer molecules,
with the accompanying loss of some small molecule (typically water). Thus, a defining
characteristic of this type of polymer is that the final polymer chain does NOT include all the
atoms initially present in the monomer molecules. Some of the atoms are lost in the small
molecule that is eliminated as the polymer chain grows.
Question 3
Indicate which step in a free-radical chain reaction happens in what order (1st, 2nd, 3rd)
First - The product of radical species from non-radical species, typically using heat or UV light.
, Second - The reaction of a radical with a non-radical, producing a new radical species. The new
radical species continues the chain reaction.
Third - The reaction of two radical species with one another, producing a non-radical species.
The lack of a reactive intermediate then stops the chain reaction.
Question 4
Match the name of each term describing the stereochemical orientation in a polymer chain to its
correct definition.
Answer
Atactic - Stereocenters have random configuration
Isotactic - All stereocenters have the same configuration
Syndiotactic - Sterocenters alternate in configuration
Question 5
A process that can form links (typically covalent bonds between growing chains of the polymer)
to tether the growing chain together in a less random (more crystalline) order.
Answer
Cross - linking
Question 6
Match the term describing the different ways of arranging two different types of monomers into a
copolymer to its correct description.
Answer
Random (statistical) copolymers - The monomeric units are distributed randomly, and
sometimes unevenly, in the polymer chain
Alternating copolymers - The monomeric units are distributed in a regular alternating fashion,
with nearly equimolar amounts of each in the chain
Block copolymers - A long sequence or block of one monomer is joined to a block of the second
monomer
Graft copolymers - Side chains of a given monomers are attached to the main chain of the
second monomer.
Exam
Question 1
Complete the following statement regarding the classification of polymers by filling in the blanks:
Polymers are large ____ made by repetitive linking of smaller units known as monomers. The
terms polymers and monomers are derived from the _____ roots poly (many), mono (one), and
_____(part). Polymers are classified as macromolecules. A macromolecule is a very large
molecule composed of thousands of _____ bonded atoms. Polymers can also be classified as
either natural or _____. Natural polymers include rubber, carbohydrates like starch or cellulose,
proteins, and nucleic acid (DNA/RNA). The biologically relevant natural polymers are sometimes
called _____. Synthetic polymers are created by scientists in a lab (not formed in nature) for
specific purposes.
Answer
1. Molecules
2. Greek
3. Meros
4. Covalently
5. Synthetic
6. Biopolymers
Question 2
Describe the major difference in the formation of addition polymers versus condensation
polymers.
Answer
A defining characteristic of a chain-growth/addition polymer is that the final polymer retains all of
the atoms of the monomers. Step-growth polymers (also known as condensation polymers) are
formed by the reaction between two different functional groups on different monomer molecules,
with the accompanying loss of some small molecule (typically water). Thus, a defining
characteristic of this type of polymer is that the final polymer chain does NOT include all the
atoms initially present in the monomer molecules. Some of the atoms are lost in the small
molecule that is eliminated as the polymer chain grows.
Question 3
Indicate which step in a free-radical chain reaction happens in what order (1st, 2nd, 3rd)
First - The product of radical species from non-radical species, typically using heat or UV light.
, Second - The reaction of a radical with a non-radical, producing a new radical species. The new
radical species continues the chain reaction.
Third - The reaction of two radical species with one another, producing a non-radical species.
The lack of a reactive intermediate then stops the chain reaction.
Question 4
Match the name of each term describing the stereochemical orientation in a polymer chain to its
correct definition.
Answer
Atactic - Stereocenters have random configuration
Isotactic - All stereocenters have the same configuration
Syndiotactic - Sterocenters alternate in configuration
Question 5
A process that can form links (typically covalent bonds between growing chains of the polymer)
to tether the growing chain together in a less random (more crystalline) order.
Answer
Cross - linking
Question 6
Match the term describing the different ways of arranging two different types of monomers into a
copolymer to its correct description.
Answer
Random (statistical) copolymers - The monomeric units are distributed randomly, and
sometimes unevenly, in the polymer chain
Alternating copolymers - The monomeric units are distributed in a regular alternating fashion,
with nearly equimolar amounts of each in the chain
Block copolymers - A long sequence or block of one monomer is joined to a block of the second
monomer
Graft copolymers - Side chains of a given monomers are attached to the main chain of the
second monomer.
