Chemistry LibreTexts. Open textbook resources for all the divisions of chemistry.

OpenStax Chemistry 2e. A comprehensive open textbook for introductory or general chemistry.

Concept Development Studies in Chemistry. An open textbook focusing on the development of chemical concepts from data and reasoning.

ptable. An openly available and interactive periodic table with elemental properties.

Concord Consortium. Interactive simulations, activities, and lesson plans for chemistry.

PhET Simulations. Interactive simulations for chemistry and more.

Khan Academy. Free educational resources for a variety of subjects, including chemistry.

Wolfram|Alpha. A "semantic calculator" that can aid problem solving (use it wisely!).