Reaction Dynamics Unit
March 3- March 10 (2016)
Day 1: Understanding Collision Theory in Reactions
Objectives (SWBAT):
Physical Science 31-Describe chemical changes and reactions using diagrams and descriptions of the reactants, products,
and energy changes
Evaluated by:
Collision Theory Worksheet
Class structure:
Do Now: Under what circumstances does sugar dissolve best in tea.
1. Engage- The class will discuss why these factors increase the “reaction rate” of the sugar and the tea.
2. Explore- Students will use the phet simulation below to explore the molecular nature of reactions.
https://phet.colorado.edu/en/simulation/reactions-and-rates
3. Explain- Students will explain how reactions are affected by energy and concentration using the
worksheet for the day.
4. Elaborate- Students will use collision theory to predict relative reaction rates of equations and how the
factors discussed in the Do Now might affect various reactions.
Summary: The rate of a reaction can be defined as the disappearance in the amount of reactant over time or the
appearance of product over time. This can be adjusted through temperature, number of particle (concentration), size of
particles, or a catalyst.
Day 2: Interpreting Reaction Rate from Graphs Using Collision Theory
Objectives (SWBAT):
Physical Science 31-Describe chemical changes and reactions using diagrams and descriptions of the reactants, products,
and energy changes
Inquiry 5- Use graphing skills to solve problems
Evaluated by:
Collision Theory Graphing Worksheet
Class structure:
Do Now: Draw an example of a potential energy graph for a reaction and label the reactants and products.
1. Engage- Class will review vocabulary (activation energy, activated complex, reactant, product) and
introduce new vocabulary (inhibitor, catalyst)
2. Explore- Students will use graphs and data to determine the rate of a reaction.
3. Explain- Students will use collision theory to explain why one experiment’s rates might differ from
another experiment’s rates.
4. Elaborate- Students will complete general multiple choice and open ended questions as practice/review
of collision theory.
Summary: The hill in the reaction progress diagram is the activation energy of the reaction. This is the amount of energy
that a reaction must have to be able to pass through the in-between state, called the activated complex, and form
products. The two things needed for a reaction to occur are reactants and energy. A higher concentration of reactants
is better and energy above the activation energy is necessary.
Day 3: Dynamic Equilibrium and Le Chatelier
Objectives (SWBAT):
Physical Science 37- Predict the direction of a shift in equilibrium in a system as a result of stress by using LeChatalier's
principle
Inquiry 5- Use graphing skills to solve problems
Evaluated by:
Prom Equilibrium
Class structure:
Do Now: Fill in the first two blanks on the sheet for today then explain which of these variables a catalyst affects.
1. Engage- Teacher will introduce forward and reverse reactions and the dynamic equilibrium between
them using a prom simulation. Students will take notes and answer questions as they follow along.
2. Explore- Students will predict changes in the shape of the concentration vs time graph with changes to
environment (music) or reactants (number of single boys, single girls, and couples).
3. Explain- Students will use the graphs they’ve drawn to explain dynamic equilibrium.
4. Elaborate- Students will apply their understanding of dynamic equilibrium and Le Chatelier’s Principle to
chemical equations.
Summary: The concentration of reactants and products at equilibrium is not equal but the rate of change for each side is
equal. The reaction direction of a reversible reaction can be predicted if the equilibrium concentrations and current
concentrations are known.
Day 4: Virtual Equilibrium Lab
Objectives (SWBAT):
Physical Science 37- Predict the direction of a shift in equilibrium in a system as a result of stress by using LeChatalier's
principle
Inquiry 6- Students will use technology to enhance scientific investigations
Evaluated by:
Virtual Equilibrium Lab
Class structure:
Do Now: Students will log into their computer and find the virtual lab for the day.
1. Engage- Students will use the background section of the lab to refresh their memories on reversibility of
reactions and dynamic equilibrium then complete the prelab questions. Teacher will check these before
students begin the lab.
2. Explore- Students will apply various stresses to reactions at equilibrium and record their observations of
what happens.
3. Explain- Students will explain what happened chemically in each reaction that led to the observations
they recorded.
4. Elaborate- Students will work on the review for the test (due Day 5) for continued practice.
Summary: When a stress is applied to a system in equilibrium, the system acts to reverse this stress and return to
equilibrium. Most reactions are reversible meaning they can proceed forward in which reactants combine to form
products or in reverse during which the products break up and reform the reactants. Any change in temperature,
pressure, or chemical concentrations can affect equilibrium and cause the reaction to proceed more often in the
forward direction (to the right) or more often in the reverse reaction (to the left) until it achieves equilibrium again.
Day 5: Review for Reaction Dynamics Test
Objectives (SWBAT):
Physical Science 31-Describe chemical changes and reactions using diagrams and descriptions of the reactants, products,
and energy changes
Inquiry 5- Use graphing skills to solve problems
Physical Science 37- Predict the direction of a shift in equilibrium in a system as a result of stress by using LeChatalier's
principle
Evaluated by:
Review for Reaction Dynamics Test
Class structure:
Do Now: What types of stresses can be applied to a system at equilibrium and what happens when they are
applied?
1.
2.
3.
4.
Engage- Class will review the lab from Day 4.
Explore- Teacher will work through the answers to the Reaction Dynamics review.
Explain- Teacher will show all work and address any questions throughout the process.
Elaborate- Teacher will review the vocabulary and equations that could appear on the test.
Summary: For a reaction to happen, there must be a high enough concentration of reactants that they hit each other
and these collisions must have enough energy (more than the activation energy) to force a change. Once a reaction
happens, reactants begin to run out and the reverse reaction then picks up speed until the rate of the forward reaction
is equal to the rate of the reverse reaction (dynamic equilibrium). This equilibrium can be changed by changes in
concentration or environment (volume, pressure, temperature) but the system will always act (shift toward one reaction
or the other) to correct the change (Le Chatelier’s Principle).
Day 6: Reaction Dynamics Test
Objectives (SWBAT):
Demonstrate at least 67 % proficiency on the standards of this unit.
Evaluated by:
Test- Reaction Dynamics
Class structure:
Do Now: Take out a calculator and something to write with, open your binder to the table of contents and place
it on the back bench, move your bags to the A/C, and clear your calculator RAM
TEST
Summary: There is only one more nine weeks to go now. Remember that all of this material, from January to May, can
appear on the final exam. Please be reviewing as you go.
Testing Preparation
GLE
Objective
Day(s) Addressed
Inquiry 5
Use graphing skills to evaluate reactions
2, 3, 5
Physical
Science 31
Describe chemical changes and reactions using diagrams and descriptions of the
reactants, products, and energy changes (Reaction Progress Diagrams)
1, 2, 5
Physical
Science 37
Predict the direction of a shift in equilibrium in a system as a result of stress by
using LeChatalier's principle
3, 4, 5
Vocabulary
Activation Energy
Activated Complex
Catalyst
Inhibitor
Assessment Design
Basic: 6 Questions
Collision Theory
Forward vs Reverse Reaction
Dynamic Equilibrium
Le Chatelier’s Principle
Standard: 12 Questions
Expanded: 6 Questions
Essential Skills and Learning Objectives
Type of
Question
(MC, CR, P)
Basic
(Remember &
Understand)
Standard
(Apply &
Analyze)
Expanded
(Evaluate &
Create)
Use graphing skills to evaluate reactions
MC/CR
1 CR
MC/CR/P
2 MC
1 MC
1 CR
4 CR
Describe chemical changes and reactions using diagrams
and descriptions of the reactants, products, and energy
changes (Reaction Progress Diagrams)
Predict the direction of a shift in equilibrium in a system as
a result of stress by using LeChatelier's principle
MC/CR
1 MC
3 CR
1 MC
2 CR
Describe the rate of a given reaction in terms of collision
theory
MC/CR
3 MC
2 CR
1 CR
2 CR