4TH SIX WEEKS EXAM CHEMISTRY

1. A chemical formula includes the symbols of the elements in the compound and subscripts that indicate

• a. atomic mass of each element
• b. number of atoms or ions of each element that are combined in the compound
• c. formula mass. d. charges on the elements or ions

2. How many atoms of fluorine are present in a molecule of carbon tetrafluoride, CF4?

• 1
• 2
• 4
• 5

3. The formula for carbon dioxide, CO2, can represent

• one molecule of carbon dioxide
• 1 mol of carbon dioxide molecules.
• the combination of 1 atom of carbon and 2 atoms of oxygen
• all of the above

15. The oxidation number of Fluorine is

• always 0
• -1 in all compounds
• +1 in all compounds
• equal to the negative charge of all the metal ions in a compound

16. What is the oxidation number of Oxygen in most compounds?

• -8
• -2
• 0
• +2

17. In a compound, the algebraic sum of the oxidation numbers of all atoms equals

• 0
• 1
• 8
• the charge on the compound

____ 18. What is the formula mass of magnesium chloride, MgCl2? a. 46 amu c. 95.21 amu b. 59.76 amu d. 106.35 amu ____ 19. The molar mass of CCl4 is 153.81 g/mol. How many grams of CCl4 are needed to have 5.000 mol? a. 5 g c. 769.0 g b. 30.76 g d. 796.05 g ____ 20. What is the mass percentage of chlorine in NaCl? a. 35.45% c. 60.7% b. 50% d. 64.5%

18. What is the formula mass of Magnesium chloride, MgCl2?

• 46 amu
• 95.21 amu
• 59.78 amu
• 106.35 amu

19. The molar mass of CCl4 is 153.81 g/mol. How many grams of CCl4 are needed to have 5.000 mol?

• 5 g
• 30.76 g
• 769.0
• 796.05 g

20. What is the mass percentage of Chlorine in NaCl?

• 35.45%
• 50%
• 60.7%
• 64.5%