SAT / PSAT
SAT / PSAT Prep
History & Social Science
AP World History AP US History AP European History AP Human Geography AP US Government & Politics AP Psychology AP Macroeconomics AP Microeconomics
English
AP English Language & Composition AP English Literature & Composition
Math & Computer Science
AP Calculus AB/BC AP Precalculus AP Statistics AP Computer Science A AP Computer Science Principles
Sciences
AP Biology AP Chemistry AP Environmental Science AP Physics 1 AP Physics 2
World Languages & Arts
AP Spanish Language AP Art History AP Music Theory Start studying →
Unit 8 · Acids & Bases Unit Hub Flashcards Cheat Sheet The Essentials Visual Review MC Practice SAQ Practice
Unit 8 · 11–15% of Exam

Acids & Bases

Proton transfer. Bronsted-Lowry acids and bases, pH and pOH of strong and weak acids/bases, molecular structure and acid strength, acid-base reactions and titrations, and the properties of buffers.

11 topics
~14–16 class periods
College Board aligned
← Back to AP Chemistry

Choose your study tool

Six ways to master Unit 8 — pick whichever fits how you like to study.

Flashcards
20 interactive flashcards covering every key term from Unit 8. Tap to flip, shuffle, and use keyboard arrows.
Open flashcards →
Cheat Sheet
A one-page visual summary of Unit 8 — every key topic, term, and theme on a single screen.
Open cheat sheet →
Essentials
The big ideas plus a searchable glossary of every vocabulary term you need to know for the exam.
Open essentials →
Visual Review
A slide-by-slide walkthrough of Unit 8 with diagrams of titration curves, buffer regions, and pH calculations.
Open visual review →
MCQ Practice
30 multiple-choice questions in College Board exam style — with full explanations of every answer.
Start practice →
SAQ Practice
A short-answer question with model answers showing exactly how each part earns its point on the exam.
Start SAQ →

Topics in Unit 8

Eleven topics from the College Board CED, in order.

Topic 8.1
Introduction to Acids & Bases
Bronsted-Lowry acids (proton donors) and bases (proton acceptors), and conjugate acid-base pairs.
Topic 8.2
pH & pOH of Strong Acids & Bases
Calculating pH directly from concentration, since strong acids and bases dissociate completely.
Topic 8.3
Weak Acid & Base Equilibria
Using Ka and Kb with ICE tables to calculate pH for weak acids and bases, which only partially dissociate.
Topic 8.4
Acid-Base Reactions & Buffers
Neutralization reactions, buffer formation, and predicting whether a salt solution will be acidic, basic, or neutral.
Topic 8.5
Acid-Base Titrations
Reading titration curves to identify the equivalence point, half-equivalence point, and buffer region.
Topic 8.6
Molecular Structure of Acids & Bases
How bond polarity, atomic size, and electronegativity predict relative acid and base strength.
Topic 8.7
pH & pKa
The relationship between pH, pKa, and the relative amounts of an acid and its conjugate base in solution.
Topic 8.8
Properties of Buffers
How a mixture of a weak acid and its conjugate base resists changes in pH when small amounts of acid or base are added.
Topic 8.9
Henderson-Hasselbalch Equation
pH = pKa + log([A⁻]/[HA]) — calculating the pH of a buffer from the ratio of conjugate base to weak acid.
Topic 8.10
Buffer Capacity
How the concentrations of the buffer components determine how much added acid or base a buffer can absorb.
Topic 8.11
pH & Solubility
How solution pH affects the solubility of ionic compounds whose anions are conjugate bases of weak acids.

About Unit 8

Unit 8 takes the equilibrium tools from Unit 7 and applies them specifically to proton-transfer reactions. You'll learn to calculate pH and pOH for strong acids and bases (which dissociate completely) and for weak acids and bases (which require an equilibrium calculation using Ka or Kb). You'll connect molecular structure — bond polarity, atomic size, electronegativity — to relative acid and base strength, read titration curves to extract pKa and equivalence point information, and understand how buffers resist pH change using the Henderson-Hasselbalch equation.

This unit is roughly 11–15% of the AP Chem exam — the second-highest weighted unit after Unit 3 — and takes about 14–16 class periods. Every equilibrium skill from Unit 7 (Q vs. K, ICE tables, Le Châtelier's principle) returns here in the specific context of acids and bases.

Two core themes run through this unit:

Theme
Structure & properties — molecular structure predicts relative acid and base strength
Theme
Equilibrium — acid-base systems follow the same Q vs. K logic as Unit 7
Explore more
Browse all 9 AP Chemistry units
View all units →