In this video lesson, Paul Andersen explains that elementary reactions are steps within a larger reaction mechanism. Colliding molecules require sufficient energy and proper orientation to break bonds and form new bonds. A unimolecular reaction mechanism requires one type of reactant and is a first-order reaction. A bimolecular reactions requires two molecules colliding and is a second-order reaction. Termolecular reactions are rare but are the colliding...

In this video lesson, Paul Andersen explains how buffer solutions maintain pH in a solution. A buffer solution is made up of a weak acid and its conjugate base. As strong acids or bases are added, the pH remains stable. A good buffer solution has a pKa value equivalent to the pH and equal amounts of the weak acid and the conjugate base.--Publisher.

In this video lesson, Paul Andersen explains how stoichiometry can be used to quantify differences in chemical reactions. The coefficients in a balanced chemical equation express the mole proportions in that reaction. These values can be used to predict the expected values, determine the limiting reactant, predict the molar mass of gases, determine the percent yield, and interpret results from a titration.--Publisher.

In this video lesson, Paul Andersen explains how disturbances to a reversible reaction at equilibrium affect the equilibrium constant and the reaction quotient. For example, if the concentration is changed, the reaction will move to reestablish the equilibrium constant. If the temperature is changed, a new equilibrium constant will be established.--Publisher.

In this video lesson, Paul Andersen explains how Le Chatelier's Principle can be used to predict the effect of disturbances to equilibrium. When a reversible reaction is at equilibrium, disturbances (in concentration, temperature, pressure, etc.) will be offset to reach a new equilibrium.--Publisher.

In this video lesson, Paul Andersen defines the equilibrium constant (K) and explains how it can be calculated in various reversible reactions. The equilibrium constant is a ratio of the concentration of the products to the concentration of the reactants. If the K value is less than one, the reaction will move to the left, and if the K value is greater than one, the reaction will move to the right.--Publisher.

In this video lesson, Paul Andersen defines and explains the importance of the mole. The mole is simply a number (like a dozen) used to express the massive number of atoms in matter. It serves as a bridge between the mass of a compound and the number of particles. It is represented in chemical reactions as the coefficient before reactants and products.--Publisher.

In this video lesson, Paul Andersen explains how the atomic model has changed over time. A model is simply a theoretical construct of phenomenon, so when we receive new data, we may have to refine our model. Ionization energy data resulted in the formation of a quantum model that more accurately reflected the atom.--Publisher.

In this video lesson, Paul Andersen explains how the reaction path can be described in an energy profile. Enough energy must be added to reach the activation energy required and stress the bonds. Eventually the bonds break and new bonds are formed. The rate constant is temperature dependent. The Arrhenius equation can be used to calculate the activation energy when the temperature and rate constant are calculated.--Publisher.

In this video lesson, Paul Andersen explains how gases differ from the other phases of matter. An ideal gas is a model that allows scientists to predict the movement of gas under varying pressure, temperature, and volume. As a gas approaches condensation, some of the ideal gas laws fall apart. A description of both the kinetic molecular theory and Maxwell-Boltzmann Distribution are included.--Publisher.