Chemistry Did you know that you are made up of chemicals? Chemistry is the study of matter: its composition, properties, and reactivity. This material roughly covers a first-year high school or college course, and a good understanding of algebra is helpful. My Projects Help Requests Community Questions Community explanations Calling great explainers of the world! Help us answer frequently asked chemistry questions by writing clear, deep, engaging explanations. Your explanation may even be selected for an article on Khan Academy (with full credit to you)! Atoms, molecules, and ions Atomic structure, atomic numbers, atomic mass, moles, ions (eventually), compounds (eventually) Chemical reactions and stoichiometry We are now going to delve into the heart of chemistry. We learn ways of representing chemical molecules and how molecules react. To do this, we'll even think about "how many" of a molecule we have using a quantity called a "mole". Electronic structure of atoms Bohr model, absorption, emission spectrum, quantum numbers, electron configurations Periodic table Classification of elements, atomic radii, ionic radii, ionization energy, electron affinity Chemical bonds Ionic bonds, metallic bonds, covalent bonds, electronegativity, Lewis dot structures, VSEPR, hybridization Gases and kinetic molecular theory Gas laws (eventually), ideal gas equation, Dalton's law (eventually), kinetic molecular theory (eventually) States of matter and intermolecular forces Intermolecular forces, liquids, solids, phase changes Chemical equilibrium Equilibrium constant, heterogeneous equilibria, le Chatelier's principle Acids and bases Definitions, pH, acid-base equilibria, buffers, titrations, solubility equilibria, and salt solutions! Buffers, titrations, and solubility equilibria We can combine our knowledge of acids and bases, equilibrium, and neutralization reactions to understand buffers and titrations. Solubility equilibria will build on concepts from solubility, precipitation, and equilibrium. Thermodynamics Thermodynamics is the study of heat, "thermo," and work, "dynamics." We will be learning about energy transfer during chemical and physical changes, and how we can predict what kind of changes will occur. Concepts covered in this tutorial include the laws of thermodynamics, internal energy, heat, work, PV diagrams, enthalpy, Hess's law, entropy, and Gibbs free energy. Redox reactions and electrochemistry Oxidation states (numbers), oxidation-reduction (redox) reactions, galvanic/voltaic Cells, electrolytic cells Kinetics Reaction rates, rate laws, Arrhenius equation, catalysts Nuclear chemistry Nuclear reactions, nuclear stability, radioactive decay Ask a chemist! (Archived) Hi, my name is Yuki and I get really excited about chemistry. Do you have a question or comment that might be related to chemistry? Ask your question between July 30 and August 2, and I will try my best to answer it. Please feel free to join in the discussion and answer some questions too!