Acids and Bases Overview — AP Chemistry
1. Unit at a Glance
This unit builds on the equilibrium fundamentals you learned in Unit 7 to describe proton transfer reactions, one of the most common and important classes of chemical reactions. We progress from core conceptual definitions to connecting structure to acid strength, then master quantitative pH calculations for all types of acids and bases, and finish with an exploration of buffer systems that resist pH change.
The learning arc moves from conceptual understanding to structured quantitative problem solving, which aligns directly with how the AP Chemistry exam assesses this topic: you will need both conceptual reasoning for multiple-choice questions and clear calculation work for free response questions.
Common Pitfalls
Why: pKa is a constant for a given acid, while pH is a property of a specific solution that depends on concentration.
Why: The small x approximation is valid when x is less than 5% of the initial acid concentration, saving time on calculations.
Why: Buffers can also be formed from a weak base and its conjugate acid.