1. The chemical symbol for silver is:

a. Hg b. Ar 
c. Si d. Sl

2. Which statement is correct:

a. elements, but not compounds are homogeneous.
b. elements, but not compounds are pure substances.
c. compounds, but not elements are homogeneous.
d. both compounds and elements are pure substances.

3. In which of the following sequences of elements do each of the elements have a two letter symbol?

a. magnesium, nickel, phosphorus
b. bromine, iron, calcium
c. aluminum, copper, sulfur
d. boron, barium, beryllium

4. In which of the following sequences of elements do each of the elements have a one letter element symbol?

a. lead, nitrogen, zinc
b. potassium, fluorine, carbon
c. tin, hydrogen, iodine
d. oxygen, silicon, chlorine

5. Which of the following is not a physical property?

a. boiling point
b. physical state
c. color
d. density

6. Which of the following involves a physical change and not a chemical change?

a. A piece of sulfur is burned.
b. A firecracker explodes.
c. A rubber band is stretched.
d. A nail rusts

7. Which of the following is a mixture?

a. Water
b. Mercury(II)
c. Sugar Solution
d. Copper(II) oxide

8. When 8.44 g of calcium are heated in air, 11.82 g of calcium oxide are formed. The percentage of oxygen in the compound is:

a. 28.6% b. 40.0%
c. 71.4% d. 1.40%

9. Mercury(II) sulfide, HgS, contains 86.2% mercury. The weight of HgS that can be made from 40.0 g of mercury is:

a. 3450 g b. 0.464 g
c. 34.5 g d. 46.4 g

10. Which of the following is a compound?

a. Lead
b. Wood
c. Potassium
d. Aluminum

11. Which of the following is a mixture?

a. Water
b. Chromium
c. Wood
d. Sulfur

12. How many atoms are represented in the formula Na₂CrO₄?

a. 3 b. 5 c. 7 d. 8

13. Which of the following does not occur as diatomic molecules?

a. O₂        b. I₂               c. H₂        d. Na₂

14. Which of the following is a property of both gases and liquids?

a. definite shape
b. indefinite shape
c. definite volume
d. indefinite volume

15. A solid substance is subjected to a number of tests and observations. Which of the following test results would be classified as a physical property of the substance?

a. it dissolves in acid and a gas is liberated.
b. it burns oxygen with a bright red flame.
c. it melts at 127^oC.
d. it changes from silvery gray to black when placed in moist air.

16. Which of the following is not a physical change?

a. burning of gasoline
b. condensing of steam
c. pulverizing of some solid sulfur
d. freezing of water

17. When a substance undergoes a chemical change it is always true that:

a. it melts
b. it changes state
c. its chemical composition changes
d. heat is evolved

18. In which of the following pairs of terms are the two members of the pair "opposite processes?"

a. evaporation and melting
b. deposition and freezing
c. sublimation and melting
d. evaporation and disposition

19. The description "two substances present, two phases present" is correct for:

a. heterogeneous mixtures
b. homogeneous mixtures
c. elements
d. compounds

20. How many atoms are represented in one formula unit of Al₂(Cr₂O₇)₃ ?

a. 33 b. 29 c. 25 d. 14