Unit 8: Kinetics and Equilibrium
Unit 8 of our 9-unit course focuses on
the topics of Kinetics and Equilibrium. We will explore details
about reaction rates, considering what variables affect the rates of
reactions and why, how reactions take place, and how experimental data
can be used to determine equations that describe reaction rates. This
is the topic of Kinetics. But we will also explore the topic of
Equilibrium. This includes topics like reversible reaction systems in
which reactants don't completely react away and what can be done to persuade
them to more fully react. We will use equilibrium equations to predict
the final concentrations and/or pressures of reactants and products.
The unit will end with a return to the topic
of acids and bases at which time we will use our completed and refined
titration system to conduct our student-designed lab investigation ...
just in time for the May 23 Maker Fair.
The unit will include the usual blend of conceptual knowledge with
mathematical analysis. There will be approximately 9 days devoted to
the unit with the first 2-3 days being focused on the topic of
Coming Soon to a Chemistry-Engineering Program Near You
In a matter of days we will begin our Spring Semester Maker Fair/Scienc Fair project. The project involves:
- The creation of a robotic titration device that uses pH
change to automatically determine the end-point of a titration (that's
in place of color change).
- The use of the device in conducting a student-designed scientific study of acids and bases.
An Arduino and a circuit board will be the brains of the auto-titration
device. The auto-titrator will have to be able to read the pH of the
solution, control a drip/squirt/pour device, measure the volume of
titrant added to the solution, and make decisions about how fast to add
titrant and when to stop the titration. Once your device works, you
will conduct your scientific study.
That's a lot of engineering. And that's a lot of chemistry! Get ready.
Our book is a little short on the topic
of the Collision Model and Reaction Mechanisms. The following page of
terminology with links to informative images may be helpful.
View Collision Model Terminology
Wednesday's & Friday's Lab
We have labs scheduled for Wednesday
and Friday. The Wednesday Lab is an outdoor lab. April 18 is usually a
great day for an outdoor lab. But because of Global Warming, it may be
too cold outside to do a lab. If the weather does not cooperate on
Wednesday, then we will swtich the two lab days around, doing
Wednesday's Lab or Friday and Friday's lab on Wednesday.
Red-Gray Simulation and the Equilibrium Position
The Red-Gray Simulation teaches us a
lot about reversible systems, the nature of equilibrium as a dynamic
system, and the concept of an equilibrium constant. In the simulation,
the ratio of Gray Cards to Red Cards at equilibrium was always 2.0. It
doesn't matter how many cards we start with, whether we disturb an
equilibrium by adding or removing cards, or whether we start with all
red or all gray cards. The ratio of Gray to Red Cards is always 2.0
provided that the rate of the forward reaction is two times greater
than the rate of the reverse reaction. All the following data prove
this important fact to you.
View Red-Gray Data Tables
Auto-Titrator Project Checklist
A good portion of your Auto-Titrator
Project will be done in Chemistry class. To successfully complete your
Auto-Titrator Project, you will have to ...
- Calibrate the dripper to relate time to volume dispensed.
- Pass check of ability to dispense a designated volume (in teacher's presence).
- Read pH probe; calibrate pH probe using pH=4 and pH=10 buffer solutions.
- Titrate sample using buttons on breadboard.
- Titrate sample programmatically based on pH reading; determine the volume at the endpoint.
- Add in mixing and titrate sample programmatically; determine the volume at the endpoint.
- Perform science experiment using auto-titrator.
- Create Poster Presentation.
Additionally, you will add in the use of pneumatics to control the movement of all equipment along a track
in order to fully automate the system. This part will be done in Engineering class.
Periodic Table in Pictures and Words
FREE: A Chemistry Study Tip
Stretching out your studies over a
lengthy period of time so that there are many "visits" of the material
is far better than lengthier, less-frequent sessions of intense
studies. So what's this have to do with Chemistry class? I'm going to
A little Chemistry each day helps. Your homework usually includes two
WebAssigns - one is a "looking ahead" WebAssign in which you read about
something that is coming up next. The other is a "looking behind"
WebAssign in which you practice using something that we just learned in
class. So why not do the "Looking behind" WebAssign on the evening of
the Blue day - the day you were presented with the material. And then
do the "Looking ahead" WebAssign on the evening of the Gold day - the
evening just prior to when we cover the material the next morning.
Hopefully that makes sense ... and it gives you a little Chemistry
every day. =SIGH=
page changes nearly every day; re-load
or refresh to receive the most recent schedule.
|>> Friday, April 20 <<
- What is a reaction mechanism and how can potential mechanisms be evaluate in light of a rate law equation?
- What is equilibrium and how is it related to reaction rates? In what sense is it a dynamic state? And why do reaction systems attain to a state of equilibrium
- Discuss Maker Fair Project
- Method of Initial Rates: pp. 5-6, Q#5ab, 6
- Reaction Mechanisms (p. 7, Q#1ab; p. 8, Q#2abde)
- Discuss reversible systems/equilibrium
- Lab KE2: Red-Grey Equilibrium Simulation
- Discuss: Chapter 17:3-4 Reading Guide (pp. 11-12)
- If time allows: discuss "equlibrium position", reaction quotient, and K expressions; start p. 13
Time in Class
|>> Tuesday, April 24 <<
We will complete our discussion of reaction mechanisms, discuss the
concepts of equilibrium position, equilibrium constant expression, and
predicting equilibrium concentrations using ICE Tables.