1. Ms. Samayoa Birmingham community charter high school Chemistry
Kinetics
Ms. Samayoa
Birmingham community charter high school
Chemistry

2. Learning Objective: Students will understand the underlying factors that affect chemical reaction rates by creating a school dance analogy.
Academic Vocabulary: kinetics, rate of a reaction, Collision Theory, activation energy, and catalyst

3. Introduction
Kinetics is the study of rates and mechanisms of chemical reactions
Rate is the speed at which a reaction is taking place
A mechanism is a series of reactions that lead to final products of a reaction

4. Collision Theory
According to Collision Theory, chemical reactions occur because reactants are constantly moving around and colliding with one another

5. Effective Collision Effective collisions occur when
reacting particles collide with sufficient (right amount of) kinetic energy
at proper orientation (angle)

6. Rate of a Reaction
Rate of a reaction depends on frequency of (how often) effective collisions occur between particles
Any factor that can change the frequency of effective collisions between reacting particles will change the rate of that reaction

7. How do we change the speed of a reaction?

8. Concentration and Reaction Rate
Increasing concentration increases rate of a reaction because there will be more particles to collide, and the frequency of effective collisions will increase
Decreasing concentration decreases the rate of a reaction because there will be fewer particles to collide, and the frequency of effective collisions will decrease

9. Concentration and Reaction Rate
More H2 gas is produced when magnesium (Mg) is placed in acidic solution of a higher concentration (4M) than in acidic solution of lower concentration (2M)

10. Temperature and Reaction Rate
Increasing temperature of reacting solutions increases rate because energy of particles increase, resulting in an increase in the frequency of effective collisions
Decreasing temperature of reacting solutions decreases rate because energy of particles will decreases, resulting in a decrease in the frequency of effective collisions

11. Pressure and Reaction Rate
Increasing pressure on a reaction that involves gases increases the reaction rate because the concentrations of the reactants will increase due to a decrease in the volume of the system
Decreasing pressure on a reaction that involves gases decreases the reaction rate because the concentrations of the reactants will decrease due to an increase in the volume of the system
At a higher pressure of 2 atm, the volume of the reaction is decreased, resulting in greater concentration of reactants
Therefore, reaction at the higher pressure will be faster

12. Surface Area and Reaction Rate
Surface area is the amount of exposed area of a set of mass of a solid substance
Increasing surface area of a solid increases reaction rate because there will be more exposed areas for effective collisions to occur
Decreasing surface area of a solid decreases reaction rate because there will be fewer exposed areas for effective collisions to occur

13. Activation Energy and Catalysts
Activation energy is the energy needed to start a chemical reaction.
ALL chemical reactions require some amount of activation energy
Chemical reactions that require low activation energy are faster than those that require high activation energy

14. Activation Energy

15. Activation Energy and Catalysts
A catalyst is a substance that can increase the speed (rate) of a reaction by lowering the activation energy
A catalyst in a reaction provides an alternate (lower activation energy) pathway for a reaction to occur faster

16. Catalyst