chem PP

chem PP - Chem 1004- Spring 2011 GWU M.G.Z. Additional...

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Chem 1004- Spring 2011 GWU M.G.Z. 1 Additional Practice Problems 1 1. The widespread applicability of plastics is a consequence of the ability of chemists to customize the properties of plastics by altering their molecular structures. In a sense, the scientists "design" the desired properties of plastics into their constituent molecules. In doing so, they follow one or more of only six general strategies for modifying polymer chains. The strategies involve altering the following features of the polymer chain: 1. the length of the chain (the number of monomer units), 2. the three-dimensional arrangement of the chains in the solid, 3. the branching of chains, 4. the chemical composition of the monomer units, 5. the bonding between chains, and 6. the orientation of monomer units within the chain. The following figures represent these 6 strategies. Assign each figure to one of the strategies described above. A B C D E F 2. High-density polyethylene is composed of A. primarily linear, unbranched chains of polyethylene in a close packing arrangement B. primarily highly branched, non-linear chains of polyethylene in a diffuse packing arrangement C. a mixture of polyethylene and polystyrene D. polyethylene with high density plastizers added to increase density
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Chem 1004- Spring 2011 GWU M.G.Z. 2 3. Thermoplastic polymers may be A. heated and reformed B. heated, but not reformed C. decomposed by heating D. changed in color by heating 4. Which term describes "a polymer made from two different monomers"? A. Addition polymer B. Thermosetting polymer C. Co-polymer D. Thermoplastic polymer 5. Which is a principal difference between high-density polyethylene (HDPE) and low-density polyethylene (LDPE)? I. They are made from different monomers. II. LDPE has a lot of side chains. III. LDPE is more rigid than HDPE. IV. LDPE is an addition polymer while HDPE is a condensation polymer. A. Only I B. I, III, and IV C. Only II D. II and III 6. Which is not generally a difference between an addition polymer and a condensation polymer? A. Both types of polymers can be recycled. B. They use different types of starting monomers. C. Condensation polymers are natural; addition polymers are synthetic. D. In a condensation polymer, a portion of the monomer is not incorporated in the final polymer. 7. Which is not a method used to manipulate the properties of polymers? A. Form the polymer from two different monomers. B. Use a condensation reaction on addition type monomers. C.
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This note was uploaded on 03/02/2011 for the course CHEM 004 taught by Professor Zysmilich during the Spring '06 term at GWU.

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chem PP - Chem 1004- Spring 2011 GWU M.G.Z. Additional...

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