Reacation Rates

Reaction Rates, Collision Theory, and Potential Energy Diagrams : 

Reaction Rates, Collision Theory, and Potential Energy Diagrams

Reaction Rates and Collision Theory : 

Reaction Rates and Collision Theory Vocabulary: Learn to use these words and include them in your work today. Reaction rate Collision theory Activation energy Catalyst Enzyme

Reaction Rate : 

Reaction Rate Speed of a reaction How fast a reactant is used up How fast a product is produced

Collision Theory : 

Collision Theory Particles collide during a reaction. Force of collisions (temperature) Number of collisions (concentration)

Activation Energy : 

Activation Energy Minimum amount of energy needed to break bonds in reactants (so new bonds in products can form)

Catalyst : 

Catalyst Substance that increases rate of reaction without taking part in reaction Lowers the activation energy.

Enzymes : 

Enzymes Biological catalyst

Increasing Reaction Rates : 

Increasing Reaction Rates Heating a reaction will cause the particles to move faster and will allow them to reach the activation energy. This results in a higher rate. A higher concentration will cause more collisions that could result in the particles reaching the activation energy. This results in a higher rate.

Increasing Reaction Rates : 

Increasing Reaction Rates Increasing the surface area of the reactants will allow the particles to collide more often which will allow them to achieve the activation energy. This will result in a higher rate. Adding a catalyst will lower the activation energy, which will allow the particles to achieve the activation energy. This will result in a higher rate.

Potential Energy Diagram : 

Potential Energy Diagram Potential Energy Diagrams show the change in energy during a chemical reaction. The left side is always the reactants. The right side is always the products. In the middle is the activated complex, where the reactants combine. The energy needed to form the activated complex is known as the activation energy.

Potential Energy Diagram : 

Potential Energy Diagram

Endothermic Reaction : 

Endothermic Reaction In the previous slide, you have an endothermic reaction. You can tell this because the energy of the products is higher than the energy of the reactants. This means energy was absorbed by the products.

Potential Energy Diagram : 

Potential Energy Diagram

Exothermic Reaction : 

Exothermic Reaction In the previous slide, you have an Exothermic reaction. You can tell this because the energy of the products is lower than the energy of the reactants. This means energy was released into the system.

Potential Energy Diagram : 

Potential Energy Diagram

Activation Energy : 

Activation Energy Notice in the previous slide, the highest peak on the potential energy diagram is where the activated complex is. In order for the reaction to start, the two reactants must collide with enough energy. Notice that the forward reaction has a lower activation energy than the reverse reaction. This means that it is easier for the forward reaction to occur than the reverse.

Potential Energy Diagrams : 

Potential Energy Diagrams

Catalysts : 

Catalysts Notice in the previous slide that the reaction has a certain activation energy. Look what happens to the activation energy when a catalyst is added. The activation energy is lowered. This means that it requires less energy for the reaction to occur. The reaction should occur at a faster rate.