CLASS SET OF INSTRUCTIONS:
Lab: Evidence of Chemical Change
All matter has physical and chemical properties by which it can be classified. Examples of
physical properties include color, odor, density, hardness, structure, solubility and melting
and boiling point.
Chemical properties are determined by the reaction of a substance with other substances.
Examples of chemical properties are combinations with acids and bases, reactions with oxygen and other
active gases, and the reactions of a substance with other compounds.
To determine if a change is chemical or physical, ask yourself this question: Does the change alter the type
of substance? If the shape, size, or physical state is changed but the chemical composition or type of matter
remains the same, the change is a physical change.
In a chemical change, which is also called a chemical reaction, the atoms of a substance are rearranged to
form a new substance. A chemical change requires that the new substance has a chemical composition that is
different from the composition of the original substance.
Some signs of chemical changes are: color change, the formation of a solid (called a precipitate), bubbling
and fizzing (gas production), and a temperature change through light or heat production (the release of
energy).
Mass is not destroyed or created during any chemical change. The Law of Conservation of Mass states that
the mass of what you end with (the products) is always equal to the mass of what you start with (the
reactants).
Purpose: Demonstrate that substances may react chemically to form new substances.
Procedure:
1. Put on your safety goggles and your lab apron. Keep them on the entire period. Go to your assigned station.
2. Each station has a STATION task instructions and all of the supplies and materials you will need to
complete the procedures at that station.
3. Read each tasks instructions thoroughly, follow the steps listed, and record your observations on your
data table.
4. When you have completed the task at each station, follow the directions for clean up of
your materials.
5. You will have approximately 15 minutes to complete each station. However, do not rotate to the next
station until you are instructed to do so by your teacher.
6. If you have extra time at a station, complete your conclusion questions.
EACH Station will allow for one team member to be a materials manager, another team member should be
the videographer. You should have one opportunity to do each.
The Materials manager is responsible for returning and clean up of all station materials.
Videographer is responsible for acquiring iPad and making video of observations each day. Images/Videos
should be named according to date.classperiod.groupname example 3.25.1st.divas.
Adapted from “Chemical Changes Stations” at http://www.science-class.net/Chemistry/changes_reactions.htm
Name: _____________________________________ Date: ______________GROUP _____ Per:___
Lab: Evidence of Chemical Change
Conclusion Questions:
1. Identify 4 signs that indicate a chemical change has taken place.
2. What do all of the changes you observed have in common?
3. For all stations, why is it important to use a different spoon and/or stirrer for each dry
chemical?
4. A yellow liquid is mixed with a colorless liquid and begins to bubble. Then a yellow solid is formed at the
bottom of the container. Has a chemical reaction taken place? If so, what evidence do you have to prove it?
5. A red solid is placed in sunlight and after a period of time it becomes an opaque, brown solid. Has a
chemical reaction taken place? If so, what evidence do you have to prove it?
6. A silver metal when lit, reacts with oxygen in the air and produces light and heat. Has a chemical reaction
taken place? If so, what evidence do you have to prove it?
7. When initial mass of substances was taken, then substances combined, was the final mass of the
materials different than if they are combined on paper ? Was mass created, destroyed or constant ?
Explain your observations.
8. What does the Conservation of Mass/Matter Law State ? How does this support a balanced chemical
equation ?
9. List all Observations of Chemical Changes that you observed:
Adapted from “Chemical Changes Stations” at http://www.science-class.net/Chemistry/changes_reactions.htm
Name: _____________________________________ Date: ______________GROUP _____ Per:___
Observations:
Time Began:
Station 1: Baking Soda and Calcium Chloride
Materials Manager:
Videographer:
Substance
Physical Properties (3-5 descriptors)
MASS
INFORMATION
Observed Changes
Baking Soda
Calcium Chloride
Baking
Soda/Calcium
Chloride Mixture
Water
Phenol Red
Describe the evidence that shows a
chemical reaction has taken place.
Time Began
Substance
Station 2: Cornstarch and Iodine
Physical Properties (3-5 descriptors)
Materials Manager:
Videographer:
Observed Changes
Cornstarch
Water
Cornstarch/Water
Mixture
Iodine
Describe the evidence that shows a
chemical reaction has taken place.
Adapted from “Chemical Changes Stations” at http://www.science-class.net/Chemistry/changes_reactions.htm
Time Began:
Substance
Station 3: Epsom Salts and Washing Soda
Physical Properties (3-5 descriptors)
Materials Manager:
Observed Changes
Videographer:
Epsom Salts
Epsom Salts/Water
Mixture
Washing Soda
Washing
Soda/Water
Mixture
Water
Describe the evidence that shows a
chemical reaction has taken place.
Time Began
Substance
Station 4: Pennies, Salt and Vinegar
Physical Properties (3-5 descriptors)
Materials Manager:
Videographer:
Observed Changes
Copper Penny
Salt
Vinegar
Describe the evidence that shows a
chemical reaction has taken place.
Adapted from “Chemical Changes Stations” at http://www.science-class.net/Chemistry/changes_reactions.htm
Adapted from “Chemical Changes Stations” at http://www.science-class.net/Chemistry/changes_reactions.htm