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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 Kinetics.

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:
  1. 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).
  2. 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.

Collision Model

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 ...
  1. Calibrate the dripper to relate time to volume dispensed.
  2. Pass check of ability to dispense a designated volume (in teacher's presence).
  3. Read pH probe; calibrate pH probe using pH=4 and pH=10 buffer solutions.
  4. Titrate sample using buttons on breadboard.
  5. Titrate sample programmatically based on pH reading; determine the volume at the endpoint.
  6. Add in mixing  and titrate sample programmatically; determine the volume at the endpoint.
  7. Perform science experiment using auto-titrator.
  8. 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

For those who are connoisseurs of periodic tables or simply would like to relish a great moment of geekery, tap the link below and explore on this interactive periodic table of the elements.

Visit Interactive Periodic Table with Words and Pictures.

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 tell you:

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=

    Online Homework


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Today in Class

>> Friday, April 20 <<

Focus Question(s):
  • 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


Next 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.

Periodic Tables

Are you in need of a periodic table?  Try one of the following websites:

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