Tools for Teachers

Tools for Teachers

Chemistry

Prepared by the Shodor Education Foundation with support from:

Table of Contents

· Purpose 3

· Draft lesson plans by Topic

- Chemical Bonding 4

- Solubility Rules 5

- Electrolytes 10

- ionic and Net ionic Equations 25

- Photoelectron Inquiry Activity 34

- H2 + Cl2 Limiting Reactant 41

· National Science Digital Library. 45

· Useful Web Links 49

Purpose

In June 2006 North Carolina chemistry teachers gathered at a workshop hosted by the shodor education foundation.

Their goal was produce inquiry lesson plans that would be of immediate value to both new teachers and more seasoned teachers.

The lesson plans were to include, as much as possible, resources from the National Science Digital Library (NSDL) and computational science tools from Shodor’s Computational Science Education Reference Desk (CSERD).

This is a summary of the draft lesson plans that were produced along with a list of links and other information that those attending the workshops found to be particularly useful.

Please use these lessons, change them and improve them. Send the changes to us at: or or

Let us know if you find the NSDL and other resources useful.

Our thanks to the following teachers who carefully and thoughtfully put together the lesson plans in this document:

Ken Carter

Antoinette Cheek

Guido Gabbrielli

Cathy McLuskey

John Pritchett

Chuck Roser

Ragan Spain

Laura Stiles

CHEMICAL BONDING

Learning Objective: To identify the differences between ionic and covalent bonding.

NC Standards: 2.06, 2.07

Pre-Requisite: An understanding of the difference between metals and non-metals

and their respective locations on the Periodic Table.

Skills: Quantitative measurement, data reading, data analysis

Strand: Nature of science, science as inquiry, science and technology

Safety Precautions: If the conductivity of the solutions are actually measured

instead of using the virtual lab, safety goggles should be worn at

all times and students should not breathe fumes. Hands should

be thoroughly washed after the lab.

Science Concepts: Ionic and covalent bonding

Materials: AlCl3, KOH, CaCl2, C12H22O11, CH3OH, C5H12, distilled water, six beakers, stir rod and conductivity meter

Procedure:

1) Virtual Lab

a. Go to the site www.conductivitylab.com

b. Follow the instructions and determine if the light shines brightly for the following 6 compounds

i. AlCl3

ii. KOH

iii. CaCl2

iv. C12H22O11

v. CH3OH

vi. C5H12

c. Complete the data table

2) Actual lab

a. Mark the six beakers with the names of the six compounds .

b. Put 100 mL of distilled water in four of the six beakers.

c. Add one scoop of the first four compounds listed to the beakers labeled with their names to the distilled water and stir with the stir rod. (Rinse and dry the stir rod between each addition.)

d. Put the conductivity probe into the beaker and make certain that the tip is completely under the surface of the solution.

e. Record whether the light shines or does not shine on the data sheet.

f. Repeat steps d and e for the other three solutions.

g. Put 100 mL of CH3OH and 100 mL of C5H12 into the remaining two beakers and cover with a lid.

h. Repeat steps d and e for each of the new compounds. Do not breathe the fumes from either beaker. Only remove the lids long enough to perform the test.

Data Table:

NAME / FORMULA / LIGHT SHINES
(YES or NO)
Aluminum Bromide / AlBr3
Potassium Hydroxide / KOH
Calcium Chloride / CaCl2
Sucrose / C12H22O11
Methanol / CH3OH
Pentane / C5H12

Questions:

1. Group the compounds based on their ability to enable the light to shine.

2. Using the blank outline of the periodic table supplied, insert the different elements.

3. What is the main difference between the two groups?

4. To which group would you expect LiOH, C2H5OH and NaC2H3O2 to belong?

5. The presence of ions is necessary to conduct electricity. Which group should be labeled as Ionic and which group Covalent?

Teacher Notes:

1. At the end of the questions a more detailed description of the different types of bonding should be given. Suggested internet sites to use in the description are :

a. http://www.dlt.ncssm.edu/TIGER/Flash/bonding/CovalentBonding.html

b. http://www.dlt.ncssm.edu/TIGER/Flash/bonding/IonicBonding.html

c. http://www.ithacasciencezone.com/chemzone/lessons/03bonding/mleebonding/metallicbonding.htm

d. http://www.dlt.ncssm.edu/TIGER/Flash/moles/Dissolving_NaCl-Electrolyte.html

e. http://www.dlt.ncssm.edu/TIGER/Flash/moles/Dissolving_Sugar_Non-electrolyte.html

2. A good follow-up exercise would be for the students to identify ten simple chemical compounds that they use in their homes and use the Periodic Table to determine if the compounds are ionic or covalent.

3. If the virtual lab is used then it is suggested that one or two live demonstrations are incorporated.

4. This may be a good point to introduce the student to nomenclature.

SOLUBILTY RULES

Learning Objective: To understand the solubility rules and how to apply them

NC Standards: 5.01

Pre-Requisite: An understanding of the difference between ionic and covalent

bonding.

Skills: Quantitative measurement, data reading, data analysis

Strand: Nature of science, science as inquiry, science and technology

Safety Precautions: If the conductivity of the solutions are actually measured

instead of using the virtual lab, safety goggles should be worn at

all times and students should not breathe fumes. Hands should

be thoroughly washed after the lab.

Science Concepts: Solubility

Materials: AlCl3, KOH, CaCl2, AgCl, HC2H3O2, C12H22O11, CH3OH, C5H12, distilled

water, six beakers, stir rod and conductivity meter

Solubility Rules:

Soluble

· All nitrates, acetates, ammonium and Group 1 salts

· All chlorides, bromides and iodides except silver, lead and mercury (I)

· All fluorides except Group IIA, lead (II) and iron (II)

· All sulfates except calcium, strontium, barium, mercury, lead (II) and silver

Insoluble (0.10 M or greater)

· All carbonates and phosphates except Group IA and ammonium

· All hydroxides except Group IA, strontium and barium

· All sulfides except Group IA, IIA and ammonium

· All oxides except Group IA

Procedure:

3) Virtual Lab

a. Go to the site www.conductivitylab.com

b. Follow the instructions and determine if the light shines brightly or weakly for the following eight compounds

i. AlCl3

ii. KOH

iii. CaCl2

iv. AgCl

v. HC2H3O2

vi. C12H22O11

vii. CH3OH

viii. C5H12

c. Complete the data table

4) Actual lab

a. Mark the eight beakers with the names of the eight compounds .

b. Put 100 mL of distilled water in six of the eight beakers.

c. Add one scoop of the first six compounds listed to the beakers labeled with their names to the distilled water and stir with the stir rod. (Rinse and dry the stir rod between each addition.) Cover the acetic acid solution with a lid.

d. Put the conductivity probe into the beaker and make certain that the tip is completely under the surface of the solution.

e. Record whether the light shines, weakly shines or does not shine on the data sheet.

f. Repeat steps d and e for the other five solutions.

g. Put 100 mL of CH3OH and 100 mL of C5H12 into the remaining two beakers and cover with a lid.

h. Repeat steps d and e for each of the new compounds. Do not breathe the fumes from either beaker. Only remove the lids long enough to perform the test.

Data Table:

NAME / FORMULA / LIGHT SHINES
(YES, WEAKLY or NO)
Aluminum Bromide / AlBr3
Potassium Hydroxide / KOH
Calcium Chloride / CaCl2
Silver Chloride / AgCl
Acetic Acid / HC2H3O2
Sucrose / C12H22O11
Methanol / CH3OH
Pentane / C5H12

Questions:

6. Group the compounds based on their ability to enable the light to shine, shine weakly and not shine.

7. Did any of the covalent compounds allow the light to shine? If the answer is no, explain.

8. Did all the ionic compounds cause the light to shine brightly? If the answer is no, explain.

9. Based on the Solubility Table, what would happen to the light if 0.10 M solutions of CuSO4, Cr2S3, Li2O, FeF3 and (NH4)3PO4 were tested?

10. Using the textbook, or the internet, determine the color of all the solutions.

11. Using the Periodic Table, provide an explanation of the findings in question 5.

12. Did any covalent compounds cause the light to shine weakly? If the answer is yes, explain.

Teacher Notes:

5. At the end of the questions a more detailed description of solubility should be given. Suggested internet sites to use in the description are :

a. http://www.dlt.ncssm.edu/TIGER/Flash/moles/Dissolving_NaCl-Electrolyte.html

b. http://www.dlt.ncssm.edu/TIGER/Flash/moles/Dissolving_Sugar_Non-electrolyte.html

c. http://www.dlt.ncssm.edu/TIGER/Flash/equilibrium/Solubility_of_AgCl.html

d. http://www.dlt.ncssm.edu/TIGER/Flash/electrochem/WeakAcidEquilibrium.html

6. If the virtual lab is used then it is suggested that one or two live demonstrations are incorporated.

Strong, Weak, and Non-Electrolytes

This lesson includes:

· Teacher demonstration

· Computer Animations

· Lecture Notes

· Student Notes

· Interactive Power Point Assessment

· Student Assignment

Learning Objectives

Students will use electrical conductivity to:

· Distinguish among strong, weak, and non-electrolytes.

· Compare degrees of dissociation of strong and weak acids and bases.

Standards: 2.06, 2.07, 5.04

Strands: Science as Inquiry, The Nature of Science, Science and Technology

Safety Precautions: If the conductivity of the solutions are actually measured

instead of using the virtual lab, safety goggles should be worn at

all times and students should not breathe fumes. Hands should

be thoroughly washed after the lab.

Science Concepts: solubility, properties of ionic and covalent compounds, degree of

ionization/dissociation, electrolytes

Materials: conductivity tester, water vinegar, sucrose solution, sodium chloride solution

Internet, LCD projector

Student note sheet, Teaches notes

(Note: Student note sheet can be projected on a white board and students can record information as

teacher provides it. A Smart Board may also be used as a way to present student notes.)

Lesson Outline

I. A. Begin lesson with a demo using a conductivity tester that turns on a light bulb when in an electrolytic solution: water, sugar, vinegar, and sodium chloride

C. If a conductivity tester is not available and you have access to the Internet and a LCD projector, use the following animation to show conductivity of the three solutions:

http://ithacasciencezone.com/chemzone/lessons/07acidbase/electrolyte.htm

http://www.shodor.org/teachers/media/flash/chemapp.swf

B. Students record on their note sheet whether the light bulb comes on bright, dim, or off.

C. Have students suggest what they think is happening to each solute to cause the different observations.

II. A. Show the following animations at http://www.dlt.ncssm.edu/TIGER/chem2.htm#stoich

i. Dissolving sugar

ii. Dissolving sodium chloride

B. As Students watch each animation; they should complete each illustration on their note sheet.

C. After students have completed both illustrations, have them predict by illustrating on their note sheet what happens to the acetic acid solution to cause the light bulb to come on dimly.

D. Show the following animations at http://www.dlt.ncssm.edu/TIGER/chem6.htm

i. Strong acid ionization

ii. Weak acid equilibrium

E. After students have watched each animation, they should describe and illustrate on their note sheet what happens to each acid when dissolved in water.

III. Simply define electric currents: Electric current is the flow of electric charge.

IV. A. Define the following terms. Students should record the definitions on their note sheet

i. Strong electrolyte

ii. weak electrolyte

iii. non-electrolyte

B. Show the following animations:

http://ithacasciencezone.com/chemzone/lessons/07acidbase/electrolyte.htm

Students should complete the illustrations on their handout as they view these animations by indicating if the light bulb is off, bright or dim and by indicating the species that are present in each solution that the conductivity tester is placed in and if each solution is a non-, weak, or strong electrolyte.

V. Provide students with the rules for deciding which compounds are non-, weak, or strong electrolyte

VI. Power Point Tutorial

VII. Assignment

Conductivity Demonstration Observations

· In the data table below, record what happens to the light bulb as each substance/solution is tested with the conductivity tester.

Data Table 1.

Substance/Solution / Light Bulb
Water, H2O
Sucrose, C12H22O11 (aq)
Sodium chloride, NaCl (aq)
Vinegar/Acetic Acid, HC2H3O2 (aq)

· What do you think happens when each substance – sucrose, sodium chloride, and acetic acid – are dissolved in water to cause the light bulb to remain off or come on brightly or dimly?

______

Dissolving of sucrose (sugar) in water

· View the animation of the sugar dissolving in water.

· Complete the illustration below to show what is happening to the sugar molecules as they dissolve.

Dissolving of sodium chloride (salt) in water

· View the animation of the sugar dissolving in water.

· Label the large and small particles as a positive sodium ion, Na+1, and negative chloride ions, Cl-1.

· Complete the illustration below to show what is happening to the sodium and chloride ions as they dissolve.

· Based on your observations of the dissolving of sucrose and sodium chloride in water, illustrate what you believe happens to the acetic acid, HC2H3O2, when it dissolves in water to turn the light bulb on dimly.

· Watch the animation of a strong acid ionization. http://www.dlt.ncssm.edu/TIGER/chem6.htm

· Describe and illustrate what happens to the acid when dissolved in water.

· Do all acid molecules ionize?______

· Watch the animation of a weak acid equilibrium. http://www.dlt.ncssm.edu/TIGER/chem6.htm

· Describe and illustrate what happens to the acid when dissolved in water.

· Do all acid molecules ionize? ______

· Referring back to your illustration of the dissolving of sucrose (sugar), describe how the two acid ionizations are different from the dissolving of sucrose in water.

______

Electric current –

Electrolytes–

· Strong electrolyte -

· Weak electrolyte -

· Non- electrolyte -

Complete the illustrations as you view the electrolyte animations:

http://ithacasciencezone.com/chemzone/lessons/07acidbase/electrolyte.htm

______

· In the blank below each container above, label each solution above as a strong, weak or non-electrolyte.

How to decide if a compound is a non-electrolyte, weak electrolyte, or strong electrolyte.

Strong electrolytes

· Strong acids – HCl, HBr, HI, H2SO4, HNO3, HClO4, HClO3