3. Rephrase to “What is the formula mass of Na2CO3 if the atomic weights are

as follows: Na=23g, C=12g, and O=16g?

a. 106 amu

b. 89 amu

c. 57 amu

d. 51 amu

4. Which of the following is the correct representation of a chloride ion?

a. Cl0

b. Cl-1

c. Cl2

d. Cl

5. Which of these is the correct formula of Iron (III) Sulfate?

a. Fe2(SO4)3

b. Fe(SO4)2

c. Fe3(SO4)2

d. FeSO4

6. How many moles on iron does 25.0g of Fe represent, if the molar mass of Fe

is 55.85g?

a. 80.9 moles of Fe

b. 30.9 moles of Fe

c. 2.23 moles of Fe

d. 0.45 moles of Fe

7. A compound is formed when 1 atom of sulphur combines with 3 atoms of

oxygen. What is the correct formula of the compound?

a. S3O

b. SO3

c. (SO)3

d. (SO2)3

8. Tetra phosphorus trisulphide is used on the tops of “strike anywhere”

matches. The formula for tetra phosphorus trisulphide is ___.

a. P2S5

b. P4S3

c. P3S4

d. P2S3

9. Which of the following is an empirical formula?

a. C3H6

b. CH4

c. C2H6

d. C4H10​