1. SC-100 Class 15 Review Questions
1. Sublimation occurs when
a. a liquid turns into a solid.
b. an atom accepts electrons when combining with other elements.
c. electrons are transferred from an atom to other elements.
d. a solid turns directly into a gas.
e. a liquid turns directly into a gas.

2. SC-100 Class 15 Review Questions
2. Which state of matter maintains a constant volume but not a fixed shape?
a. gas
b. plasma
c. liquid
d. crystal
e. solid

3. SC-100 Class 15 Review Questions
3. Sodium Chloride (Na + Cl - ) atoms form a crystal lattice that is held together by
a. hydrogen bonds.
b. salt bonds.
c. covalent bonds.
d. ionic bonds.
e. van der Waals bonds.

4. SC-100 Class 15 Review Questions
4. Exothermic and endothermic chemical reactions differ in that
a. energy is given off only in exothermic reactions.
b. energy is given off only in endothermic reactions.
c. the total energy in all involved atoms is the same before and after an exothermic reaction.
d. the total energy in all involved atoms is the same before and after an endothermic reaction.
e. only exothermic reactions can be observed in everyday life.

5. SC-100 Class 15 Review Questions
5. Most polymers are characterized as being
a. a collection of small molecules combined into long chains.
b. interesting to study, but having little value in our lives.
c. permanently stable compounds.
d. found in synthetic products, but not in nature.
e. strong and brittle.

6. SC-100 Class 15 Review Questions
6. How does the number of electrons in the outer shell determine the chemical characteristics of an element?
Determines the kind of bonds that will form; ionic, metallic, or covalent.

7. SC-100 Class 15 Review Questions
7. How do you neutralize an acid? Give an example. Add a base (alkali)
HCl + NaOH  NaCl + H2O

8. SC-100 Class 15 Review Questions
8. What are the three kinds of chemical bonding? Give an example of each.
Ionic: NaCl
Metallic: Copper
Covalent: Methane