1. What is the name and molar mass of the following compound: NH4NO3
a. Ammonium nitrate 80.043 g/mol
2. What is the name and molar mass of the following compound: BeO
a. Beryllium oxide 25.01158 g/mol
3. What is the formula and molar mass of the following compound: Aluminum arsenide
a. AlAs 101.9031 g/mol
4. How many moles are in 76.2 grams of sodium sulfate?
a. Na2SO4 142.04 g/mol
b. 0.536 mols
5. How many grams are in 5 mols of vanadium(V) fluoride?
a. VF5 145.85 g/mol
b. 729.25 g
6. What is Avogadro’s number?
a. 6.022 x 1023
7. How many atoms are in 0.25 mols of sodium?
a. 1.5055 x 1023
8. How many moles is 4 million (4 x 106) molecules of CO2?
a. 6.64 x 10-18 moles CO2
9. What is the weight in grams of 7.5 billion molecules of Magnesium oxide, MgO?
a. 1.245 x 10-14 mols MgO
b. 5.02 x 10-13 grams MgO
10. An unknown hydrate of cobalt(II) chloride is found to have a molar mass of 238 g/mol. What is
its formula?
a. Cobalt(II) chloride = 129.839 g/mol
b. Mass of H2O = 18.01528 g/mol
c. 238 – 129.839 = 108.161/18.01528 = 6 water molecules
d. CoCl2 dot 6H2O
11. Nitrogen trifluoride is used in the integrated circuit manufacturing industry. How many nitrogen
trifluoride molecules are in a 0.88 mole sample, and what is the formula for nitrogen trifluoride?
a. 5.3 x 1023 molecules NF3
12. How many oxygen atoms are in 14 grams of sodium hydrogen carbonate?
a. NaHCO3 84.007 g/mol
b. 0.167 mols NaHCO3
c. 1.003 x 1023 molecules NaHCO3
d. 3.01 x 1023 atoms O
13. Lithium carbonate is used to treat bipolar disorder, in conjunction with psychotherapy.
Determine the percentage composition by mass of lithium carbonate.
a. Li2CO3 73.891 g/mol
b. Percentage Li = 18.8%
c. Percentage C = 16.25%
d. Percentage O = 64.96%