Overview and Background: Unit:

 

 

select understandings

 

Name:  Renée Teague

Science : Science : Science

Cheney High : Grades 10-12 : day : Aug. - May.

 

Title:

Dear Professor Science

Topics:

Reaction Rates, Equilibrium and Le Chatelier's Principle

Time Frame:

7 blocks of class time (85 minutes each).

Start Date:

-

 

Other Designers:

 

Summary:
Students perform prescribed laboratory experiments designed to teach what factors affect reaction rates and then write a series or one newspaper column answering questions about everyday occurrences.

 

Print Materials Needed:
Reaction Rate Factors information sheet,  Reaction Rate Factors 1-4 labs, Equilibrium Lab

Resources:

 

Resource Attachments:

Internet Resource Links:

 

Notes:

 

 

Stage 1: Identify Desired Results

 

State:

KS  

Title:

Physical Science – Chemistry 2A:3.7

Standard(s):

Students will assess the interrelationships between the rate of chemical reactions and variables such as temperature, concentration, and reaction type.

 

Understandings:

Certain factors affect the rate of chemical reactions.

Patterns in chemical reactions allow for predictions and classifications.

A chemical equation is a statement of process predicting products.

Chemical equilibrium is a system in dynamic balance where rates of forward and reverse reactions are equal. Changes in temperature and concentration perturb equilibrium by influencing the rates of simultaneous reactions unequally.

 

Essential Questions:

What factors increase or decrease reaction rate?

 

Knowledge and Skills:

K

The components of a chemical reaction.

Kinetic Molecular theory.

 

S

How to write chemical equations. 

 

Stage 2: Determine Acceptable Evidence

 

Assessment Summary:
Students write a newspaper column (or series) of columns answering questions based upon lab experience with support and descriptions of the labs performed and conclusions.

Student Directions:

You write a column for the school newspaper called, "Ask Professor Science" in which students ask questions about natural or unnatural phenomena.  You have done well answering most question, however, there is one annoying student (a member of the debate team) who keeps challenging your answers, citing a lack of evidence to support them.  He has asked six questions about reaction rates that you feel you can answer reasonably well, based on your own lab experience.  Here they are:

1.  Why do refrigerators prevent food from spoiling?

2.  Why does it seem as if the hotter the climate in a country, the spicier its food?

3.  How can a chemical manufacturer speed up a chemical reaction that runs too slowly to be economical?

4.  Why are there warning signs on bottles of oxygen cautioning against smoking or using near open flames?

5.  I understand the chemical reaction that darkens some eyeglasses when they are in bright light is a reversible chemical reaction.  Explain how this must work.

 

Remember, Herb Farmer (the natural debater) is a stickler for evidence supporting your answer!  Also, from his past arguments, one can assume he is not as learned in science as you are, so you must explain any scientific terms you use.

 

Rubric:

http://www.cheney268.com/science/teague/AskProfScienceRubric.htm

Other assessment evidence to be collected:

Lab Write-ups

 

Stage 3: Plan Learning Experiences and Instruction

 

Learning Activities:

Iron filings in burner flame, yet cast iron over campfire doesn't burn!

Show questions at beginning of unit they will write on at the end.  MUST PAY ATTENTION in lab.

Lab:  Reaction Rate Factors  :  Surface area

  Discuss Grain Elevator explosions

Lab:  Reaction Rate Factors:  Heat

Lab:  Reaction Rate Factors:  Concentration

   Return Lab write-ups and discuss

Discuss Collision Theory as an explanation for what they have seen.

    Does it fit with Kinetic Molecular Theory already studied?

    Does it explain the three factors we have seen in lab?

Lab:  Reaction Rate Factors:  Catalysts

 

Introduce equilibrium with a demonstration using 2 empty milk jugs, labeled "reactants" (3/4 filled with water) and "products" (empty)

Discuss LeChatelier's principle

Lab:  Shifts in equilibrium