An article discussing how chemical reactions make and break bonds between atoms.

Learn how basic elements form molecules to support life.

This slide and audio book shows how to relate mass to a number of particles by using many formulas, examples, and real life scenarios. View the weighted average calculations, Avogadro's number, the atomic mass of carbon, and molar mass.

Online biology textbook discussing the chemical nature of water, and the importance of its molecular structure to life. Also discusses at length the organic molecules nucleic acids, proteins, lipids, and carbohydrates.