Chemistry can feel like a different language at first: symbols, formulas, tiny particles you cannot see, and math that seems to appear out of nowhere. This free online course helps you translate it all into clear ideas you can actually use. Instead of memorizing disconnected facts, you will learn how chemists think—how atoms explain properties, how patterns in the periodic table predict behavior, and how a balanced equation becomes a reliable tool for solving real problems.
You will build a strong foundation starting from elements, atoms, ions, and electron structure, then connect that structure to bonding and the shapes and formulas of substances. As your understanding grows, you will practice turning chemical relationships into calculations: working with the mole and Avogadro’s number, moving between mass and composition, and making sense of stoichiometry so you can predict amounts of reactants and products with confidence. Along the way, the course steadily strengthens the problem-solving habits that matter most in school and exam settings.
The course also guides you through big, high-impact topics that often determine whether chemistry feels manageable or overwhelming. You will learn how gases behave using the ideal gas equation and partial pressures, how states of matter and intermolecular forces shape boiling points and solubility, and how equilibrium connects to reaction direction through ideas like Q and K. Acids and bases become more intuitive with pH, pKa, buffers, and titration reasoning that focuses on understanding rather than shortcuts.
To round out the picture, you will explore kinetics, oxidation states and redox reactions, electrochemical cells, nuclear decay, and the thermodynamics behind energy, spontaneity, entropy, and free energy. With guided videos and targeted exercises, this course is designed to help you study more effectively, improve grades, and prepare for standardized chemistry exams—at your own pace, from anywhere.
Course content
Video class: Introduction to chemistry | Atoms, compounds, and ions | Chemistry | Khan Academy07m
Exercise: What is the essence of chemistry according to the video?
Video class: Elements and atoms | Atoms, compounds, and ions | Chemistry | Khan Academy13m
Exercise: The most basic unit of an element is the:
Exercise: What defines the element of an atom?
Video class: Introduction to the atom | Chemistry of life | Biology | Khan Academy21m
Exercise: What defines the identity of an element in chemistry?
Video class: Orbitals | Electronic structure of atoms | Chemistry | Khan Academy13m
Exercise: How is the electron configuration for Lithium described?
Video class: More on orbitals and electron configuration | Chemistry | Khan Academy14m
Exercise: What is the electron configuration for helium?
Video class: Electron Configurations10m
Exercise: What happens when electrons fill the d and f subshells?
Video class: Electron configurations 2 | Electronic structure of atoms | Chemistry | Khan Academy10m
Exercise: What is the electron configuration for nickel?
Video class: Noble gas configuration (old, low volume)06m
Exercise: What is the noble gas notation for silicon?
Video class: Noble gas configuration | Electronic structure of atoms | Chemistry | Khan Academy06m
Exercise: What is the noble gas notation for calcium (Ca)?
Video class: Valence Electrons15m
Exercise: How many electrons do atoms want to have in their outermost shell?
Video class: Groups of the Periodic Table11m
Exercise: What makes noble gases unique among elements in the periodic table?
Video class: Periodic Table Trends: Ionization Energy12m
Exercise: Which element has the highest ionization energy?
Video class: Other Periodic Table Trends15m
Exercise: Which element has the highest second ionization energy?
Video class: Ionic, covalent, and metallic bonds | Chemical bonds | Chemistry | Khan Academy13m
Exercise: What type of bond forms between sodium and chlorine to create table salt (NaCl)?
Video class: Molecular and Empirical Formulas15m
Exercise: Choose the option that shows, respectively, a molecular formula and an empirical formula
Video class: The mole and Avogadro's number | Atoms, compounds, and ions | Chemistry | Khan Academy09m
Exercise: What is the purpose of a mole in chemistry?
Video class: Formula from Mass Composition12m
Exercise: What is the empirical formula based on given mass composition?
Video class: Another mass composition problem | Chemistry | Khan Academy06m
Exercise: What is the empirical formula of a substance with 2.04% hydrogen, 65.3% oxygen, and 32.65% sulfur?
Video class: Balancing Chemical Equations14m
Exercise: How do you balance a chemical equation?
Video class: Stoichiometry | Chemical reactions and stoichiometry | Chemistry | Khan Academy09m
Exercise: How many grams of aluminum are needed to react with 85 grams of iron(III) oxide in a balanced chemical equation?
Video class: Stoichiometry: Limiting reagent | Chemical reactions and stoichiometry | Chemistry | Khan Academy15m
Video class: Ideal gas equation: PV = nRT | Chemistry | Khan Academy09m
Video class: Ideal gas equation example 1 | Chemistry | Khan Academy10m
Video class: Ideal gas equation example 2 | Chemistry | Khan Academy13m
Video class: Ideal gas equation example 3 | Chemistry | Khan Academy05m
Video class: Ideal gas equation example 4 | Chemistry | Khan Academy05m
Video class: Introduction to partial pressure | Gases and kinetic molecular theory | Chemistry | Khan Academy06m
Video class: Partial pressure example | Chemistry | Khan Academy15m
Exercise: Each pascal unit represents
Video class: States of matter | States of matter and intermolecular forces | Chemistry | Khan Academy19m
Video class: States of matter follow-up | States of matter and intermolecular forces | Chemistry | Khan Academy08m
Video class: Specific heat, heat of fusion and vaporization example | Chemistry | Khan Academy14m
Video class: Chilling water problem | States of matter and intermolecular forces | Chemistry | Khan Academy11m
Video class: Phase diagrams | States of matter and intermolecular forces | Chemistry | Khan Academy12m
Video class: Van der Waals forces | States of matter and intermolecular forces | Chemistry | Khan Academy11m
Video class: Covalent networks, metallic crystals, and ionic crystals | Chemistry | Khan Academy09m
Video class: Vapor pressure | States of matter and intermolecular forces | Chemistry | Khan Academy18m
Video class: Suspensions, colloids and solutions | Chemistry | Khan Academy13m
Video class: Solubility and intermolecular forces | Chemistry | Khan Academy13m
Video class: Boiling point elevation and freezing point depression | Chemistry | Khan Academy14m
Video class: Introduction to kinetics | Energy and enzymes | Biology | Khan Academy15m
Video class: Reactions in equilibrium | Chemical equilibrium | Chemistry | Khan Academy14m
Video class: Group trend for ionization energy | Periodic table | Chemistry | Khan Academy03m
Video class: Keq intuition | Chemical equilibrium | Chemistry | Khan Academy12m
Video class: Keq derivation intuition | Chemical equilibrium | Chemistry | Khan Academy15m
Video class: Heterogeneous equilibrium | Chemical equilibrium | Chemistry | Khan Academy09m
Video class: Le Chatelier's principle | Chemical equilibrium | Chemistry | Khan Academy14m
Video class: Introduction to pH, pOH, and pKw18m
Video class: Acid Base Introduction18m
Video class: pH, pOH of strong acids and bases | Chemistry | Khan Academy14m
Video class: pH of a Weak Acid17m
Video class: pH of a Weak Base13m
Video class: Conjugate acids and bases16m
Video class: pKa and pKb relationship | Acids and bases | Chemistry | Khan Academy14m
Video class: Buffers and Henderson-Hasselbalch | Chemistry | Khan Academy14m
Video class: Strong Acid Titration12m
Video class: Buffer capacity | Buffers, titrations, and solubility equilibria | Chemistry | Khan Academy10m
Video class: Weak Acid Titration10m
Video class: Titration roundup | Buffers, titrations, and solubility equilibria | Chemistry | Khan Academy11m
Video class: Introduction to Oxidation States17m
Video class: More on Oxidation States17m
Video class: Hydrogen Peroxide Correction02m
Video class: Redox Reactions14m
Video class: Galvanic Cells18m
Video class: Types of decay | Nuclear chemistry | Chemistry | Khan Academy17m
Video class: Half-life and carbon dating | Nuclear chemistry | Chemistry | Khan Academy12m
Video class: Exponential decay formula proof (can skip, involves calculus) | Chemistry | Khan Academy12m
Video class: Introduction to exponential decay | Nuclear chemistry | Chemistry | Khan Academy09m
Video class: More exponential decay examples | Nuclear chemistry | Chemistry | Khan Academy07m
Video class: Macrostates and microstates | Thermodynamics | Physics | Khan Academy18m
Video class: Quasistatic and reversible processes | Thermodynamics | Physics | Khan Academy14m
Video class: First law of thermodynamics / internal energy | Thermodynamics | Physics | Khan Academy17m
Video class: More on internal energy | Thermodynamics | Physics | Khan Academy13m
Video class: Work from expansion | Thermodynamics | Physics | Khan Academy12m
Video class: PV-diagrams and expansion work | Thermodynamics | Physics | Khan Academy15m
Video class: Proof: U = (3/2)PV or U = (3/2)nRT | Thermodynamics | Physics | Khan Academy16m
Video class: Work done by isothermic process | Thermodynamics | Physics | Khan Academy19m
Video class: Carnot cycle and Carnot engine | Thermodynamics | Physics | Khan Academy20m
Video class: Proof: Volume ratios in a carnot cycle | Thermodynamics | Physics | Khan Academy17m
Video class: Proof: S (or entropy) is a valid state variable | Thermodynamics | Physics | Khan Academy15m
Course comments: Chemistry
Fatima Hussain
Excellent pace and use of time Well delivered Good subject knowledge Training has already been put into practice. ...
Fatima Hussain
I really enjoyed this class This Course Helped Me {argue Effectively}
Abdiwali Hersi Ali
when it reaches equilibrium, the teacher didn't flow a sequence steps, though it explanation is pretty well, this course is effective!