Chemical Reactions Overview — AP Chemistry
1. Unit at a Glance
This unit builds from your foundational knowledge of moles and particles to teach you how to represent, classify, and quantify chemical reactions. We start with the basics of what defines a reaction, then move to writing net ionic equations to focus on reactive species, distinguish between physical and chemical changes, and cover different ways to visualize reactions at the particulate level. We end with quantitative stoichiometry (the core calculation for reactions) and classification of common reaction types that you will use in all subsequent AP Chemistry units.
Common Pitfalls
Why: Unbalanced equations give incorrect mole ratios, leading to wrong final results
Why: Net ionic equations only include species that undergo chemical change by definition
Why: Reactions proceed based on mole ratios, not mass ratios, so mass alone does not determine which reactant is limiting