Warm-Up May 28, 2015:  Review

1. How many magnesium sulfate molecules are in 25.0 g?
2. Find the molarity of a 750 mL solution containing 346 g of potassium nitrate.
3. Find the % composition of copper(II) chloride.
4. The percent composition of a compound is 40.0% C, 6.7% H, and 53.7% O. The molecular mass of the compound is 180.0 g/mol.  Find its empirical and molecular formulas.