Students read brief descriptions of atoms, molecules, elements, and compounds, and complete a matching exercise that pictures these particles and molecules as pieces of taffy.

In this animated activity, learners examine the terms "half-reaction," "oxidizing agent," and "reducing agent" and follow five interactive examples to balance equations for oxidation-reduction reactions. Three problems are provided as a self-check.

In this interactive object, learners use the ideal gas law to solve a practice problem.

In this interactive object, learners examine how to properly dilute hydrochloric acid.