Activity 8

1. Choose any Teaching Idea from any of the Chemistry Simulations (http://phet.colorado.edu/en/simulations/category/chemistry ) and post your results/data and/or answers on your blog.

Build a Molecule- Concept Questions: by Patricia Loeblein
1. A (picture)
2. D (both B & C)
3. A (only if it is in a water solution)
4. B (picture)
5. A (methane)
6. D (water)
7. C (chlorine)

2. Work with any of the Chemistry Simulations to create your own Teaching Idea. The criteria for this is as follows:

a. must identify and meet three (3) science education standards
b. must be original work
c. must be scientifically accurate and appropriate for the directed grade level.

Simulation: Balancing Chemical Reactions
Grade Level: High School Science (9-12 grade)
Science Education Standards:
1. D.12.4 Explain* how substances, both simple and complex, interact* with one another to produce new substances
2. D.12.6 Through investigations*, identify* the types of chemical interactions*, including endothermic, exothermic, oxidation, photosynthesis, and acid/base reactions
3. D.12.12 Using the science themes* and knowledge of chemical, physical, atomic, and nuclear interactions*, explain* changes in materials, living things, earth's features, and stars

Activity:
- Teacher will give a brief lesson on balancing chemical reactions. (how it is performed)
- Students will then have the opportunity to practice on the computer simulation on how to balance chemical reactions.
- Once students are familiar with the process and how chemical reactions are balanced, students will pair up with a partner, and further their practice through a classroom game.
- Teacher will have several chemical reactions written on a piece of paper. Students will need to identify which chemical(s) is/are listed and correctly balance the equation. When the pair of students think they have it balanced correctly they will come the the front of the room and ring a bell. All the students must stop and the teacher will determine if the pair has done it correctly. If done right that pair will get a point, if not not correctly all the students will have the opportunity to keep working until one pair comes up with the correct balanced equation. The first pair to receive 3 points will be the winner.

Example:  (this is what teacher should expect to see.)
write the balanced combustion equations for the following substances:
          CH4:         CH4 + 2O2 --> CO2 + 2H2o
          C5H12:     C5H12 + 8O2 --> 5CO2 + 6H2O
          C9H20:     C9H20 + 14O2 --> 9CO2 + 10H2O
                                          

Activity 7

1. Complete the Teaching Idea “Concept Questions for Chemistry using PhET” posted by Trish Loeblein on the pH Scale simulation at PHET (http://phet.colorado.edu/en/simulation/ph-scale). On your blog post the answers with your scientific explanations from the “Clicker Questions pH Scale” posted by Trish.

1. A (less)
2. C (greater)
3. A (less)
4.  C (greater)
5. B (the pressure goes up because more collisions are happening, but same force per collision.)
6. C ( has increased)
7. C (greater than)
8. C (greater than)
9. C (puffed out)

2. Complete the Teaching Idea “Intro to Strong and Weak Acids and Bases” posted by Chris Bires on the Acid-Base Solutions simulation (http://phet.colorado.edu/en/simulation/acid-base-solutions) and post on your blog your data and answers to the questions posed.

	Strong Acid	Weak Acid	Strong Base	Weak Base	Water
pH meter read (value)	2.0	4.5	12.0	9.5	7.0
pH paper (color)	red	orange	blue	green	yellow
Conductivity (bright/dim/none)	bright	dim	bright	dim	Very dim
Exists as Mostly (ions/molecules)	ions	molecules	ions	molecules	molecules

Procedure:

This simulation allows you to change the concentration of a strong and weak acid and base.

Complete the table below for some strong acids and bases and weak acids and bases by adjusting the concentration.

Strong Acids

Strength	Initial Acid Concentration (mol/L)	[HA] (mol/L)	[A-] (mol/L)	[H+] (mol/L)	pH
	.010 M	negligible	100x10-2	100x10-2	2
	.050 M	negligible	5.00x10-2	5.00x10-2	1.3
	.100 M	negligible	1.00x10-1	1.00x10-1	1
	1.00 M	negigible	1.00x10-0	1.00x10-0	0

Weak Acids

Strength (approximately)	Initial Acid Concentration (mol/L)	[HA] (mol/L)	[A-] (mol/L)	[H+] (mol/L)	pH
	.015 M	1.54x10-2	3.92x10-5	3.92x10-5	4.41
	.150 M	1.50x10-1	1.22x10-4	1.22x10-4	3.91
	.015 M	1.5x10-4	1.48x10-2	1.48x10-2	1.83
	.150 M	1.20x10-2	1.37x10-1	1.37x10-1	.86

Strong Bases

Strength	Initial Acid Concentration (mol/L)	[MOH] (mol/L)	[M+] (mol/L)	[OH-] (mol/L)	pH
	.010 M	Negligible	1.00x10-2	1.00x10-2	12
	.050 M	Negligible	5.00x10-2	5.00x10-2	12.70
	.100 M	Negligible	1.00x10-1	1.00x10-1	13
	1.00 M	Negligible	10x10-0	1.00x10-0	14

Weak Bases

Strength (approximately)	Initial Acid Concentration (mol/L)	[B] (mol/L)	[BH+] (mol/L)	[OH-] (mol/L)	pH
	.015 M	1.5x10-2	3.87x10-5	3.87x10-5	9.59
	.150 M	1.50x10-1	1.22x10-4	1.22x10-4	10.09
	.015 M	1.51x10-4	1.48x10-2	1.48x10-2	12.17
	.150 M	1.29x10-2	1.37x10-1	1.37x10-1	13.14

Conclusion Questions:

1.      very concentrated

2.      weak electrolyte

3.      strong electrolyte

4.    strong electrolyte

5.      decreases

6.      increases

7.     decreases

8.      As the concentration of a weak acid increases, conductivity increases / decreases / remains constant.

9.      decreases

10.  increases

11.  What are the pH values of a weak acid with a concentration of 0.10 and a strong acid with a concentration of 0.01, ten times lower?     Weak acid, 0.10 M :____4________    Strong Acid, 0.01 M :______2______