1) Which of the following polymers are made by an addition polymerization reaction?

a) Poly(sulfur)

b) Proteins, RNA and DNA

c) Polyesters

d) Nylon

e) Poly(ethylene)

2) Which one of the following statements concerning glass transition temperatures is false?

a) Above the glass transition temperature, Tg, a polymer will be an elastomer.

b) Below the glass transition temperature, Tg, a polymer will be stiff.

c) At the glass transition temperature, Tg, the polymer will form into a glass.

d) Below the glass transition temperature, Tg, the polymer will form an orderly crystalline solid.

e) Because the structure of a polymer depends on the rate of cooling, there is a ranger of temperaure (centered about Tg) where the glass can be formed.

3) Calcium chloride is added to a polymer solution of sodium alginate to cross-link the polymers, reating a thicker mixture which is used to add texture of food (like milk shakes). What is the explanation for why this happens?

a) dipole-dipole interactions between polymer chains

b) metallic ions between polymer chains

c) hydrogen bonding between polymer chains

d) covalent cross-linking between polymer chains

e) ionic bonding between polymer chains