Lesson Plan : Evidences of Chemical Reactions
This lesson plan is intended to be a guide to see how these demonstrations might fit in to the
lesson, information wise. This lesson plan does not contain the modes of how to teach, rather a
suggested outline of information.
Students will:


know the evidences of chemical reaction
identify signs that a reaction occurred
Hook
-
Ask students if they would like some cake → most of them will say yes.
Pull out a batch of cake batter and try to give it to students → they will say it’s not
cake
Tell them that it certainly is, it has eggs, flour, sugar… → they will point out that it
hasn’t been baked
Ask them how they know → they will say things like it doesn’t smell like cake, have
the same color/texture…
Tell them that the things they are naming are evidences of chemical reactions, and
that reactions are what you are discussing today
Lesson
1. Give students notes to fill out as you go over it (see Notes below).
2. Begin by discussing the evidences of a chemical reaction, giving the meaning and
examples students can relate too (see filled in notes below). Elephant’s Toothpaste,
Electrocute a Pickle, and Making Chalk can be done when the appropriate evidences
are gone over.
3. Split students up into groups to do the activity. Have trays set up around the room for
students to rotate through. They are to perform the reactions and list evidences that they
observe in the reaction. See Activity below for reaction instructions to give to students.
For set up purposes see the following: Fake Blood (Station 1), Al Foil and NaOH (Station
2), Colorless to White (Station 3), Ammonium Nitrate in Water and Sodium Hydroxide in
Water (both Station 4).
http://sites.jmu.edu/chemdemo
JMU Department of Chemistry and Biochemistry
Notes: Erase boxes before printing to create a notes sheet to give to students
Evidence of a Reaction
Meaning
Examples
1. Change in smell
A change is smell indicates that the
chemical properties of something
have changed.
- Hamburgers smell different
before and after they have been
cooked
- Burning paper
2. Color change
3. Gas is evolved
4. Energy is given
off
5. Temperature
change
A color change indicates that the
chemical properties of something
have changed. (Note: adding a dye
like food coloring does not count)
- Chicken changes from pink to
white when cooked
Gas that is given off when solids
and/or liquids mix
- vinegar and baking soda
mixing (CO2 is evolved)
(Note: heating a liquid to vaporize it
does not count)
- Elephant’s Toothpaste (O2 is
evolved)
This can be in the form of light or
sound
- fireworks give off light and
sound
- Electrocute a Pickle (light and
sound)
A change in temperature is another
form of energy being given off.
(Note: changing the temperature
externally by heating or cooling
does not count, the change must
come from the reaction)
6. A precipitate is
formed
- rusting of iron to iron (III) oxide
A precipitate is a solid formed from
the mixing of 2 liquids or solutions.
- breakable ice packs
- hand warmer packs
- Making Chalk (CaCO3 is
formed)
http://sites.jmu.edu/chemdemo
JMU Department of Chemistry and Biochemistry
Activity Instructions – cut reactions apart to place at each reactions station
Station 1:
1. Squirt a few milliliters of Fe(NO3)3 into the beaker
2. Squirt a few milliliters of KSCN
What evidence(s) do you observe?
Station 2:
1. Place a the aluminum foil tab in the flask
2. Put a few pellets of NaOH on the aluminum foil
3. Squirt some water onto the NaOH pellets
What evidence(s) do you observe?
Station 3:
1. Squirt a few milliliters of 0.5 M AgNO3
2. Add a few milliliter of 0.5M KCl and stir
What evidence(s) do you observe?
Station 4:
1. Dissolve 2g of ammonium nitrate in 50mL of water
2. In a separate container dissolve 2g of sodium hydroxide in 50 mL of
water
What evidence(s) do you observe?
http://sites.jmu.edu/chemdemo
JMU Department of Chemistry and Biochemistry