Clackamas Community College
Clackamas Community College: Empirical Formulas
This site presents as explanation for calculating empirical formulas from composition data. Numerous examples are given, along with practice problems.
Clackamas Community College
Clackamas Community College: Molecular Formulas
Discussion of molecular formula and how to determine it from empirical formula. Practice problems are available.
Chem Tutor
Chem Tutor: Basic Stiochiometry
Detailed discussion of stoichiometry, mols, and percents. Includes examples showing dimensional analysis (factor-lable method) and a link to the mole road map (a diagram which leads one through the stoichiometric problem-solving process).