DESCRIPTION:
A reaction between two white solids occurs when lead nitrate and potassium iodide are shaken forcefully producing a mixture of yellow and white solid products. The reaction occurs almost instantaneously when aqueous solutions of these compounds are mixed, precipitating yellow lead iodide.

Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃

In solution ions are more available and more likely to collide and thus react faster than they do in the solid state.

TOPICS COVERED:
- chemical change
- color change
- double replacement reactions
- mechanochemical reactions
- Law of Conservation of Mass
- precipitate reactions
- kinetics

MATERIALS NEEDED:
- small vial
- solid Pb(NO₃)₂
- solid KI
- test tube
- water
- 1 M Pb(NO₃)₂
- 1 M KI

PROCEDURE:
Solid Phase Reaction:
1. Combine equal masses of Pb(NO₃)₂ and KI in the vial
2. Shake forcefully until a bright yellow
Solution Reaction
1. Add ~1mL of water to the test tube
2. Add 2 drops of 1 M Pb(NO₃)₂ to the test tube
3. Add 4 drops of 1 M KI to the test tube

ADDITIONAL COMMENTS:
Using equal masses of each reactant for the solid-phase reaction works out stoichiometically because the molar masses of Pb(NO₃)₂ is approximately twice that of KI.

SAFETY:
Lead compounds are toxic to humans and the environment and thus should be disposed of properly. Safety goggles and gloves should be worn at all times, and care should be taken to avoid exposure.

REFERENCES:
“A Solid-Solid Reaction.” Nuffield Foundation. Accessed 17 June 2013 http://www.nuffieldfoundation.org/practical-chemistry/solid-solid-reaction
Shakhashiri, B.Z. Chemical Demonstrations;  University of Wisconsin Press: Madison, 1983; Vol. 1, pp 85.

Handout

DESCRIPTION:
When magnesium ribbon is placed in hydrochloric acid, hydrogen gas is produced causing the mixture to bubble.
Mg _(s) + 2HCl _(aq) → MgCl_{2 (aq)} + H_{2 (g)}

If they hydrogen gas is collected, it can be ignited to demonstrate the potential safety concerns of an evolved gas.
H_{2 (g)} + O_{2 (g)} → H₂O _(g)

TOPICS COVERED:
- chemical change
- combustion
- energy transformations
- evolution of a gas
- exothermic reactions
- light
- safety
- single replacement reactions
- synthesis reactions

MATERIALS NEEDED:
- 1M HCl (concentration does not need to be exact)
- 1 cm of Mg ribbon
- test tube
- small watch glass
- test tube rack or clamp & ring stand
- matches

PROCEDURE:
1. Clamp test tube to ring stand or place in rack
2. Add ~1mL of 1M HCl to test tube
3. Drop Mg ribbon in and cover with watch glass
4. Wait 30 seconds to a minute, remove watch glass, drop a lit match in the test tube (will make a loud “whoop”)

ADDITIONAL COMMENTS:
This is a demo that students love to do. It works well with types of reactions lessons.

SAFETY:
Safety goggles should be worn at all times. Hydrogen gas is explosive, special care should be taken.

REFERENCES:
Shakhashiri, B.Z. Chemical Demonstrations;  University of Wisconsin Press: Madison, 1983; Vol. 1, pp 26.

Handout

This lesson plan‘s topic is reaction types. In this lesson, notes are presented using this PowerPoint then students use their notes to identify the types of reaction in a lab. Bubbling Magnesium is Reaction C in this lesson.

DESCRIPTION:
As two rusty cannon balls (one covered in aluminum foil) are smashed together, sparks and a cracking sound are produced. The reaction that occurs is:
Fe₂O_{3 (s)} + 2Al _(s) → Al₂O_{3 (s)} + 2Fe _(s)
This exothermic reaction has a high activation energy that is overcome by the mechanical energy used to smash the cannon balls together. The large enthalpy change, -849 kJ/mol, offsets the overall unfavorable entropy change, -36.48 J/molK, giving a free energy change of -838 kJ/mol at 298K. When done on a larger scale, this reaction produces molten iron that is used in industry to weld railroad tracks together.

TOPICS COVERED:
- single replacement reactions
- redox
- exothermic reactions
- light
- sound
- chemical change
- energy transformations
- mechanochemical reactions
- activation energy
- thermodynamics

MATERIALS NEEDED:
- 2 rusty cannon balls
- aluminum foil

PROCEDURE:
1. Wrap 1 of the cannon balls in a layer of aluminum foil
2. Being careful that fingers are out of striking range, smash the balls together. A glancing blow works best. Practice to get the technique down before attempting in front of an audience.

ADDITIONAL COMMENTS:
To show evidence of heat produced in this reaction, the cannon balls can be smashed together with a piece of paper in between. Burnt holes will appear on the paper.
These balls can be purchased from Flinn: http://www.flinnsci.com/store/Scripts/prodView.asp?idproduct=16124
The Thermit Welding Company has information on the modern version of the railroad track welding process: http://www.thermit-welding.com/thermit_welding_process.php

SAFETY:
Safety goggles should be worn at all times. Gloves will protect hands from iron oxide. Sparks may fly up to several feet, caution should be taken with flammable objects in the surrounding area.

REFERENCES:
“Smashing Thermit Reaction.” Chem Fax! Flinn Scientific, Inc. 2009.
Shakhashiri, B.Z. Chemical Demonstrations;  University of Wisconsin Press: Madison, 1983; Vol. 1, pp 85.

Handout

VMI STEM Education Conference Series
This conference (October 8-10, 2013) is open to K-12 teachers as well as high school students. Teachers will receive 14 professional development hours. The conference provides opportunities for everyone involved to come away with a deeper appreciation for STEM and the current research occurring in these fields. Click here to register for this conference: http://www.vmi.edu/Conferences/STEM/STEM_2012/Attendee_Registration/

DESCRIPTION:
When 50mL of water and50mL of ethanol are combined in a 100mL graduated cylinder, the resulting mixture has a volume of ~97mL. Intermolecular interactions between water molecules in a pure sample involve hydrogen bonding, though the details of these complex interactions are not completely understood.  Some models predict transient ice-like structures within liquid water, where the local density of the sample is temporarily diminished. Ethanol and water molecules are also attracted to each other through hydrogen bonding. The ethanol likely interrupts the transient ice-like structures present in liquid water, resulting in a slight contraction of the sample. This activity demonstrates that volume isn’t always conserved.

TOPICS COVERED:
- intermolecular forces
- hydrogen bonding
- physical change
- miscibility
- mixtures

MATERIALS NEEDED:
- two 50mL graduated cylinders
- 100mL graduated cylinder
- 95% ethanol
- distilled water

PROCEDURE:
1. Measure out exactly 50mL of 95% ethanol in a 50mL graduated cylinder
2. Measure out exactly 50mL of water in a 50mL gradated cylinder
3. Pour both liquids into a 100mL graduated cylinder

ADDITIONAL COMMENTS:
Food coloring can be added to help visualize. Get students involved by having them read the graduated cylinders, it’s a good time to reinforce how they are read.

SAFETY:
Safety goggles should be worn at all times.

REFERENCES:
Meszaros, M. “The Lost Volume.” Caroline Biological Supply Company. Accessed May 31, 2013. http://www.carolina.com/teacher-resources/Interactive/chemistry-lost-volume-demonstration/tr10785.tr

STORY:
Ask students what 50 + 50 is equal to. This sets up an expectation for them.

Handout

Kevin founded the ChemDemo project with Casey Rogers in 2010. He has graduated from Colgate University with a BA in Chemistry in 1996 and from Emory University with a Ph. D in Chemistry in 2001. He was a teaching and research postdoctoral associate at the Georgia Institute of Technology from 2001-2003. He is currently an Associate Professor at James Madison University in the Department of Chemistry & Biochemistry.
Kevin’s Research Page: http://www.jmu.edu/chemistry/people/caran.shtml

Favorite Demo: Hydrogen Balloons!

Email: carankl@jmu.edu

Casey founded the ChemDemo project with Kevin Caran in 2010. Since then she has graduated from JMU with a BS in Chemistry (’12) and an MAT (’13). Now she is a high school chemistry teacher at Goochland High School in Goochland, Virginia. She continues working on the ChemDemo project, adding content and managing some of the ChemDemo web presence.

Favorite Demo: Colored Flames

Email: rogersce@dukes.jmu.edu

Natalie joined the ChemDemo project in 2013. She is an rising sophomore chemistry major at JMU who is interested in demonstration outreach.

Favorite Demo: CO2 Bubbles

Email: coppolng@dukes.jmu.edu

High School Course

This course has 45 videos over 7 hours. There are 12 question assessments throughout the course. Once the course is completed documentation is provided for professional development credit. Videos can also be viewed individually if not seeking credit.

Middle School Course

This course has 40 videos over 6 hours, There are 12 questions assessments throughout the course. Once the course is completed documentation is provided for professional development credit. Videos can also be viewed individually if not seeking credit.

Free Rice

The site works by using the money generated from ads on the site (that are only displayed when you get a question right) to pay for the rice. Each correct questions earns 10 grains of rice, and it takes an average of 400 grains of rice  to feed a person for a day. You can create a free login so that you can keep track of your rice counts over time. FreeRice suggests students register as under 14 (even if they are not) to protect their information. For more information on this see: http://freerice.com/teachers

Subjects

By using the “subject” tab at the top you can pick from a variety of subjects. The chemical symbols are a good way for students to become more familiar with element symbols and give back. This is more engaging for students than using flash cards, and it helps those in need. The SAT prep category may also be useful for students who are looking to take this test.