# Chemistry

Videos on chemistry (roughly covering a first-year high school or college course).

• ##### Introduction to the Atom
Salman Khan

The atom, proton, neutron and electron.

• ##### Orbitals
Salman Khan

An introduction to orbitals.

• ##### More on Orbitals and Electron Configuration
Salman Khan

More intuition on orbitals. Touching on electron configuration.

• ##### Electron Configuration 1
Salman Khan

Introduction to using the periodic table to determine electron configuration.

• ##### Electron Configuration 2
Salman Khan

Figuring out configurations for the d-block elements.

• ##### Valence Electrons
Salman Khan

Looking at valence electrons to figure out reactivity.

• ##### Groups of the Periodic Table
Salman Khan

Properties of alkali, alkaline earth and transition metals. Halogens and noble gases.

• ##### Periodic Table Trends: Ionization
Salman Khan

What an ion is. Using the periodic table to understand how difficult it is to ionize an atom.

• ##### Other Periodic Table Trends
Salman Khan

Electronegativity, metallic nature and atomic radius.

• ##### Ionic, Covalent, and Metallic Bonds
Salman Khan

Introduction to ionic, covalent, polar covalent and metallic bonds.

• ##### Molecular and Empirical Formulas
Salman Khan

Introduction to molecular and empirical formulas. Calculating molecular mass.

• ##### The Mole and Avogadro's Number
Salman Khan

Introduction to the idea of a mole as a number (vs. an animal).

• ##### Formula From Mass Composition
Salman Khan

Figuring out the empirical formula from a molecules mass composition.

• ##### Another Mass Composition Problem
Salman Khan

Another exercise converting a mass composition to an empirical formula.

• ##### Balancing Chemical Equations
Salman Khan

The art of balancing equations in chemistry!

• ##### Stoichiometry
Salman Khan

Introduction to stoichiometry.

• ##### Stoichiometry: Limiting Reagent
Salman Khan

Stoichiometry problem where we have a limiting reagent!

• ##### Ideal Gas Equation: PV=nRT
Salman Khan

Intuition behind the ideal gas equation: PV=nRT.

• ##### Ideal Gas Equation Example 1
Salman Khan

Figuring out the number of moles of gas we have using the ideal gas equation: PV=nRT.

• ##### Ideal Gas Equation Example 2
Salman Khan

PV/T is a constant. Figuring out the volume of an ideal gas at standard temperature and pressure (STP).

• ##### Ideal Gas Equation Example 3
Salman Khan

Figuring out the mass of Oxygen we have.

• ##### Ideal Gas Equation Example 4
Salman Khan

Figuring out the molar mass of a mystery molecule at STP.

• ##### Partial Pressure
Salman Khan

Figuring out the partial pressures of various gases in a container.

• ##### States of Matter
Salman Khan

Introduction to the states or phases of matter.

• ##### States of Matter Follow-up
Salman Khan

More on Plasma and Hydrogen bonds.

• ##### Specific Heat, Heat of Fusion and Vaporization
Salman Khan

Specifict heat and phase changes: Calculating how much heat is needed to convert 200g of ice at -10C to 110 degree steam.

• ##### Chilling Water Problem
Salman Khan

How much ice at -10 degrees C is necessary to get 500g of water down to 0 degrees C?

• ##### Van Der Waals Forces
Salman Khan

Van Der Waals Forces: London Dispersion Forces, Dipole Attractions, and Hydrogen Bonds.

• ##### Covalent Networks, Metallic, and Ionic Crystals
Salman Khan

Covalent Networks, Metallic, and Ionic Crystals: Some of the strongest molecular structures.

• ##### Vapor Pressure
Salman Khan

Vapor Pressure, Volatility, and Evaporation.

• ##### Suspensions, Colloids and Solutions
Salman Khan

Suspensions, Colloids and Solutions. The difference between Molarity and Molality.

• ##### Solubility
Salman Khan

Solubility of salt and gas solutes in liquid solvent.

• ##### Boiling Point Elevation and Freezing Point Supression
Salman Khan

Raising or lowering the boiling or freezing point of a solution by adding solute.

• ##### Introduction to Kinetics
Salman Khan

Kinetics, activation energy, activated complex and catalysts.

• ##### Reactions in Equilibrium
Salman Khan

Equilibrium reactions and constants.

• ##### Mini-video on Ion Size
Salman Khan

Correcting a mistake and learning a bit about ion size.

• ##### Keq Intuition
Salman Khan

A probabilistic look at how molecules react to develop the intuition behind the equilibrium constant formula.

• ##### Keq Derivation Intuition
Salman Khan

A more concrete attempt at showing how the probabilities of molecules reacting is related to their concentration.

• ##### Heterogenous Equilibrium
Salman Khan

Ignoring the solution or the solid state molecules when calculating the equilibrium constant.

• ##### Le Chatelier's Principle
Salman Khan

Le Chatelier's Principle regarding the "stressing" of reactions in equilibrium.

• ##### Introduction to pH, pOH, and pKw
Salman Khan

Autoionization of water into hydronium and hydroxide ions. pH, pOH, and pKa.

• ##### Acid Base Introduction
Salman Khan

Arrhenius, Bronsted Lowry, and Lewis Acids and Bases.

• ##### pH, pOH of Strong Acids and Bases
Salman Khan

Calculating the pH or pOH of strong acids and bases.

• ##### pH of a Weak Acid
Salman Khan

Calculating the pH of a weak acid.

• ##### pH of a Weak Base
Salman Khan

pH of .2 M of NH3 (weak base).

• ##### Conjugate Acids and Bases
Salman Khan

Introduction to conjugate acids and bases.

• ##### pKa and pKb Relationship
Salman Khan

The pKa and pKb relationship between conjugate acids and bases (both of which are weak).

• ##### Buffers and Hendersen-Hasselbalch
Salman Khan

Buffers and the Hendersen-Hasselbalch equation.

• ##### Strong Acid Titration
Salman Khan

Strong acid titration and equivalence point.

• ##### Weak Acid Titration
Salman Khan

Equivalence point when titrating a weak acid.

• ##### Titration Roundup
Salman Khan

Making sure you fully understand titration curves.

• ##### Introduction to Oxidation States
Salman Khan

Oxidation and reduction. Oxidation states.

• ##### Hydrogen Peroxide Correction
Salman Khan

Correcting an error in the last video regarding hydrogen peroxide.

• ##### Redox Reactions
Salman Khan

Oxidation reduction (or redox) reactions.

• ##### Galvanic Cells
Salman Khan

Redox reactions to drive Galvanic Cells.

• ##### Types of Decay
Salman Khan

Alpha, Beta, Gamma Decay and Positron Emission.

• ##### Half-Life
Salman Khan

Introduction to half-life.

• ##### Exponential Decay Formula Proof
Salman Khan

Showing that N(t)=Ne^(-kt) describes the amount of a radioactive substance we have at time T. For students with background in Calculus. Not necessary for intro chemistry class.

• ##### Introduction to Exponential Decay
Salman Khan

Introduction to Exponential Decay.

• ##### More Exponential Decay Examples
Salman Khan

A few more examples of exponential decay.

• ##### Macrostates and Microstates
Salman Khan

The difference between macrostates and microstates. Thermodynamic equilibrium.

• ##### Quasistatic and Reversible Processes
Salman Khan

Using theoretically quasi-static and/or reversible processes to stay pretty much at equilibrium.

• ##### First Law of Thermodynamics/Internal Energy
Salman Khan

First law of thermodynamic and Internal Energy.

• ##### More on Internal Energy
Salman Khan

Getting more intuition of internal energy, heat, and work.

• ##### Work from Expansion
Salman Khan

How a system can do work by expanding.

• ##### PV-diagrams and Expansion Work
Salman Khan

Why work from expansion is the area under the curve of a PV-diagram.

• ##### Proof: U=(3/2)PV or U=(3/2)nRT
Salman Khan

Conceptual proof that the internal energy of an ideal gas system is 3/2 PV.

• ##### Work Done by Isothermic Process
Salman Khan

Isothermic and Adiabatic processes. Calculating the work done by an isothermic process. Seeing that it is the same as the heat added.

• ##### Carnot Cycle and Carnot Engine
Salman Khan

Introduction to the Carnot Cycle and Carnot Heat Engine.

• ##### Proof: Volume Ratios in a Carnot Cycle
Salman Khan

Proof of the volume ratios in a Carnot Cycle.

• ##### Proof: S (or Entropy) is a Valid State Variable
Salman Khan

Prroof that S (or entropy) is a valid state variable.

• ##### Thermodynamic Entropy Definition Clarification
Salman Khan

Clarifying that the thermodynamic definition of Entropy requires a reversible system.

• ##### Reconciling Thermodynamic and State Definitions of Entropy
Salman Khan

Long video explaining why entropy is a measure of the number of states a system can take on (mathy, but mind-blowing).

• ##### Entropy Intuition
Salman Khan

A discussion of what entropy is and what it isn't.

• ##### Maxwell's Demon
Salman Khan

Maxwell's Demon: A thought experiment that seems to defy the 2nd Law of Thermodynamics.

• ##### More on Energy
Salman Khan

More clarification as to what entropy is and what entropy is not.

• ##### Efficiency of a Carnot Engine
Salman Khan

Definition of efficiency for a heat engine. Efficiency of a Carnot Engine.

• ##### Carnot Efficiency 2: Reversing the Cycle
Salman Khan

Seeing how we can scale and or reverse a Carnot Engine (to make a refrigerator).

• ##### Carnot Efficiency 3: Proving That it is the Most Efficient
Salman Khan

Proving that a Carnot Engine is the most efficient engine.

• ##### Heat of Formation
Salman Khan

Standard heat of formation or standard enthalpy change of formation.

• ##### Hess's Law and Reaction Enthalpy Change
Salman Khan

Using Hess's Law and standard heats of formation to determine the enthalpy change for reactions.

• ##### Gibbs Free Energy and Spontaneity
Salman Khan

Intuition behind why spontaneity is driven by enthalpy, entropy and temperature. Introduction to Gibbs free energy.

• ##### Gibbs Free Energy Example
Salman Khan

Determining if a reaction is spontaneous by calculating the change in Gibbs Free Energy.

• ##### Rigorous Gibbs Free Energy/Spontaneity Relationship
Salman Khan

More formal understanding of why a negative change in Gibbs Free Energy implies a spontaneous, irreversible reaction.

• ##### A Look at a Seductive But Wrong Gibbs/Spontaneity Proof
Salman Khan

A look at why the "proof" of the relation between changes in Gibbs Free Energy and Spontaneity is wrong in many textbooks.

• ##### Stoichiometry Example Problem 1
Salman Khan

Figuring grams of reactants and product produced from reaction of phosphorous and chlorine.

• ##### Stoichiometry Example Problem 2
Salman Khan

Stoichiometry Example Problem 2.

• ##### Limiting Reactant Example Problem 1
Salman Khan

Limiting Reactant Example Problem 1.

• ##### Empirical and Molecular Formulas from Stoichiometry
Salman Khan

Empirical and Molecular Formulas from Stoichiometry.

• ##### Example of Finding Reactant Emperical Formula
Salman Khan

Example of Finding Reactant Empirical Formula.

• ##### Stoichiometry of a Reaction in Solution
Salman Khan

Stoichiometry of a Reaction in Solution.

• ##### Another Stoichiometry Example in a Solution
Salman Khan

Another Stoichiometry Example in a Solution.

• ##### Molecular and Empirical Forumlas from Percent Composition
Salman Khan

Molecular and Empirical Forumlas from Percent Composition. Example 2.9 from Kotz Chemistry book.

• ##### Acid Base Titration
Salman Khan

Using acid-base titration to find mass of oxalic acid.

• ##### Spectrophotometry Introduction
Salman Khan

Spectrophotometry, Transmittance, Absorbance and the Beer-Lambert Law.

• ##### Spectrophotometry Example
Salman Khan

Spectrophotometry Example - Determining concentration based on absorbance.

• ##### Hess's Law Example
Salman Khan

Hess's Law Example.

• ##### Vapor Pressure Example
Salman Khan

Vapor pressure example using the Ideal Gas Law.

• ##### Change of State Example
Salman Khan

Specific Heat Capacity and Enthalpy of Vaporization example.