Chapter 8B Name________________Mr. Bennett Date__________

1. Find the percentage of oxygen in the following compounds:

a. KMnO4 b. SiO2 c. Mg3(AsO4)2

2. How many grams of oxygen are in 75.75 grams of SiO2?

3. Find the empirical formula if:

a. the compound contains 35.9 % Al and 64.1 % S b. you have 35.6 % P and 64.4% O

c. the cpd is 38.7 % Ca, 20.0 % P, and 41.3 % O d. it is 6.05 % Li, 45.2 % Cr, and 48.7 % O

e. the compound contains 7.88 g of aluminum, 14.06 g of sulfur, and 28.06 g of oxygen.

4. What is the molecular formula of a compound:

a. that has an empirical formula of CH and a mass of 78.1 g/mol ?

b. that has 0.44 g of H, 6.92 g of O and a mass of 34.00 u.

c. that contains 85.6 % carbon and 14.36 % hydrogen. Mass = 42.1 g/mol

d. that is 56.38 % P, 43.62 % O, and 219.9 u.

5. 1.996 grams of an oxide contains 0.606 grams of nitrogen and has a mass of 92.0 g/mol, what is the molecular formula?

6. Find the formula for the following hydrates:

a. 0.391 grams of LiSiF6 and 0.0903 g of H2O

b. 0.737 g of Mg SO3 and 0.763 g of H2O

c. 95.3 g of Li NO3 and 74.7 g of H2O

d. 76.9 % of CaSO3 and 23.1 % H2O

e. 89.2 % BaBr2 and 10.8 % H2O