Chapter 9

Question 1

What are polymers?

Answer 1

-monomers are used to synthesize polymers, they are repeating units
-they are linear ( straigh chain, branched) vs. circular (arranged)
-natural vs. synthetic (made in lab)

Question 2

How are polymers synthesized?

Answer 2

Addition polymerization of polyethylene
-Overall, the amount of free radicals are very small in comparison to the rest of the polymer, so it is generally omitted from the reaction equation : n C2H4 -> -(C2H4)n-

Question 3

What are the 2 factors that affect the physical properties of PE?

Answer 3

-length of each polymer: the longer the molecules is = the more forces between them, more bonds
-Branching of each polymer: more branching, lower density

Question 4

What are the steps for synthesizing polymers?

Answer 4

Step 1: R* —-> H2C = CH2
Step 2: R — C ^ H2 (alpha carbon) — CH2 —> H2C = CH2

Repeat step 2 many times (1000s more), then react with R* on the right side
R —[-C^H2 (alpha carbon) — C ! H2 (below C) -]— R n

Question 5

What is important to know about polymers through proteins? How do amino acids differ from each other?

Answer 5

Proteins are polymers bc they have repeating units, but the units are not identical
-Amino acids are constant with N-C-C
— Side chains differ each amino acid

Question 6

How many possible amino acid combinations & side chains are there?

Answer 6

20

Question 7

What is the difference between LDPE and HDPE?

Answer 7

-LDPE is made up of shorter polymers with a low density…. Breaks much easier
-HDPE is made up of longer polymers with a high density…. A little more difficult to break

Question 8

What are 3 ways to arrange the resulting PVC polymer?

Answer 8

1. Head to tail
2. Head to head, tail to tail
3. Random order (head to tail, tail to head, head to head)

Question 9

How does styrene polymerize and how is it used?

Answer 9

-Styrene is asymmetrical
-most polystyrenes are arranged in a random order
-Some are mixed with a substance that evaporates into a gas when heated, mixing with the polymer and getting trapped in the final product

Question 10

How does polyester polymerize?

Answer 10

-Ethylene glycol (alcohol) reacts with terephthalic acid (carboxylic acid) to yield an ester
The reaction of two components indicates a co-polymer that is formed by a condensation reaction

Question 11

What are plasticizers?

Answer 11

Plasticizers are additives that are small molecules that disrupt the regular structure