Chemical Reaction Rates

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A series of free High School Chemistry Video Lessons.

In this lesson, we will learn

• Reaction Rate Laws
• Reaction Rate Problems
• Potential Energy Diagrams

Reaction Rate Laws
Reaction rate laws give an equation for finding the rate of a reaction using the concentration of the reactants and the stoichiometric coefficients.
For the chemical equation
aA + bB => C
the reaction rate law is reaction rate = k[A]^m[B]ⁿ where k is a constant.
Finding and using the laws which predict reaction rates. This lesson discusses ways to measure and consider the rate of a reaction. It goes on to discuss the connection between concentration and reaction rate in terms of the Law of Mass Action and Rate Laws. Reaction Rate Problems
In class, you may often be asked to solve different types of reaction rate problems. When solving reaction rate problems, it is important to remember the reaction rate laws and the basics of balancing equations.
How to solve reaction rate problems. This video works out the detailed steps required to answer three problems involving rate, amount (mass or volume) and time.

Energy Diagrams
Energy diagrams depict the reaction progress versus energy. For exothermic reactions, the reactants are drawn above the products because their energy is greater. However, for endothermic reactions, the reactants are drawn below the products. Catalysts lower activation energy, so they decrease the size of the hump within the diagram itself.
How to graphically depict the variation in the energy of substances involved in reactions as they progress from reactants to products. Shows how a potential energy diagram can be used to determine activation energy and enthalpy change (Delta H) for forward and reverse reactions. Shows how a catalyst can affect the potential energy diagram for a reaction, and explains how a catalyst speeds up a reaction.

How to draw and label PE diagrams for exothermic and endothermic reactions and what effect adding a catalyst or inhibitor has on the diagram.