kinetics and ENERGY
Disciplinary Core Idea
Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.
Essential Question:
Why do chemical reactions occur?
Learning Expectations:
Students use evidence to develop a model in which they identify and describe the relevant components, including: the chemical reaction, the system, and the surroundings under study, The bonds that are broken during the course of the reaction, The bonds that are formed during the course of the reaction, the energy transfer between the systems and their components or the system and surroundings and the relative potential energies of the reactants and the products.
Students construct an explanation that includes the idea that as the kinetic energy of colliding particles increases and the number of collisions increases, the reaction rate increases.
Iowa Core Correlation:
HS-PS1-5: Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
HS-PS1-6. Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
Minds on Chemistry (MOCs)
MOC 1: Critical Reading *
MOC 2: Understanding Energy *
MOC 3: Understanding Chemical Kinetics *
MOC 4: Understanding Equilibrium *
MOC 5: Hydrogen
MOC 6: The Carbonated Beverage Industry *
MOC 7: Energy Transfer
MOC 8: Exothermic or Endothermic? *
MOC 9: Collision Theory *
MOC 10: Collision Model of Reaction Rates *
MOC 11: Catalysts
MOC 12: Iodine Clock, Elephant Toothpaste and Sudsy Kinetics
MOC 13: Grain Elevator Explosion and Blue Bottle
MOC 14: Whoosh Bottle and Alcohol Cannon *
MOC 15: Changes to Equilibrium *
MOC 16: ACT Prep (Endothermic and Exothermic Rxns) *
MOC 17: ACT Prep (Chemical Reaction Rates) *
MOC 18: Main Ideas. Not required, but highly recommended!
MOC 19: Jeopardy. Not required or graded, but +1 extra credit if completed by parents.
*= graded
6.1. Energy is conserved in a chemical change.
Objectives:
(a.) Apply and model (using energy bar charts) how the law of conservation of energy is sued to demonstrate that energy is neither created or destroyed in a chemical reaction.
(b.) Describe and model (using energy bar charts) how energy can be stored and transferred in a chemical system and use models to distinguish between exothermic and endothermic chemical changes.
(c.) Use experimental methods to determine the ideal ratio of reactants in a chemical reaction based on the energy change.
6.2. In order to react, the particles in a chemical reaction must collide.
Objectives:
(d.) Define chemical kinetics and list examples of reactions that occur at various speeds. Use page 10 from your student guide.
(e.) Model (using a diagram and graph) and calculate a chemical reaction rate (use figure 16.2)
(f.) Use collision theory to explain and diagram why chemical reactions do or do not occur. Use table 16.1 and figures 16.3 and 16.4 to assist you! Be sure your explanation is complete!
(g.) Explain the role activation energy has in a chemical reaction and calculate the activation energy of a reaction using an energy graph.
Links/Sources:
Section 16-1
6.3. Factors such as reactivity, concentration, temperature, surface area and catalysts affect the rate of a chemical reaction.
Objectives:
(h.) Explain and model (diagram and graph) the effects concentration, surface area, temperature and catalysts have on reaction rates.
(i.) Explain what a catalyst is and what it can and can not do.
(j.) Explain the requirements for a dust explosion (grain elevator fire) and the effect surface area has on a reaction rate and use a reaction rate graph to determine the time a reaction will occur.
Links/Sources:
Section 16-2
6.4. Many chemical reactions reach a state of chemical equilibrium in which both reactants and products are formed at equal rates.
Objectives:
(k.) Describe the role carbon dioxide and equilibrium have in a carbonated beverage.
(l.) Model and describe chemical equilibrium, identify the direction of equilibrium in chemical reactions and determine factors that can disrupt (and restore) equilibrium.
Links:
Sections 17-1 and 17-2