Physical Change vs Chemical Change Lab Introduction ... - Teacher

Physical Change vs Chemical Change Lab
Introduction
Matter has characteristics called properties that help us identify and describe it. Properties can be considered either physical
or chemical. Physical properties include: color, odor, density, hardness, structure, solubility, melting point and boiling point. These are
considered physical properties because they can be detected without changing the nature of the material. Chemical properties are
determined by a reaction of a substance with another substance. A new substance with new properties is formed during the chemical
reaction. Examples of chemical reactions include: combination with acid or base, burning (combustion), oxidation (corrosion or rusting)
or formation of a product after reacting with another substance.
A few changes are difficult to know at first if they are chemical or physical changes. The basic test is that if the shape, size, or
physical state is altered, but the chemical composition remains the same, then it is a physical change. If a new substance with new
chemical make up is formed, then a chemical change or chemical reaction has occurred. In a chemical reaction the atoms of the
substance are rearranged.
Purpose
In this activity you will carry out several procedures (and think back to previous experiments) to determine if a physical or chemical
change has occurred.
Background Answer in complete thoughts for credit!
1. What are physical changes?
2. Give at least three.
3. What are chemical changes?
4. Give at least 4 examples of evidence a chemical change has occurred.
5. When heating a test tube what direction should you point it? Be clear and specific.
6. Sketch an evaporating dish. Describe how to properly use an evaporating dish.
7. What is the Cornell method of swirling a test tube?
Materials
Evaporating dish sodium chloride two medium test tubes
Watch glass 6 M NH3 (ammonia) one small test tube
Toothpicks copper wire solid rubber stopper #1
Silver nitrate solution test tube holder Bunsen burner and ring stand
Cobalt chloride hydrate medium beaker
Data
Create a data table. Your data table must include the procedure step (A,B,C…), a description of the procedure, your initial
observational data, and your final observation data. Read the procedure before making your data table, several procedures require you
to record more than one observation. Be sure your data is clearly organized and neat. Remember Observations are anything you can
see, smell, feel, or hear. Be sure to record them at each step!
Procedure A
1. Add a small scoop of sodium chloride to a medium test tube. Fill the test tube one third of the way with distilled water. Put a rubber
stopper to fit and shake to see what happens. Record your observations.
Procedure B
2. Add several drops of silver nitrate solution (AgNO3) to the test tube. Mix by swirling the test tube using the Cornell method. Record
your observations.
Procedure C
3. Add several drops of six molar ammonia (6M NH3) into the test tube from procedure B. Quickly put the cap back on the ammonia
bottle as well as the stopper on the test tube. Gently swirl the test tube to mix the solutions. Record your observations.
4. Rinse the test tube and contents down the drain with plenty of water.

Procedure D
5. Fold up copper wire and place it inside a small test tube. Cover the wire with silver nitrate solution. Set the test tube aside for 10-15
minutes. Record initial observation and record your observations after 10-15 min.
6. Carefully dump the contents of the test tube into the trash (NOT DOWN THE SINK), and clean your test tube.
Procedure E
7. Set up your Bunsen burner and ring stand. Remember to place the evaporating dish on the wire mesh before lighting your Bunsen
burner! Place a small scoop of cobalt chloride hydrate into an evaporating dish. Heat it slowly until it changes color. Record your
observations.
8. Turn off your Bunsen burner and let the dish cool for at least 15 minutes. After the substance has cooled add some water to the solid
and record your observations.
Procedure F
9. Break three toothpicks into small pieces and put them into a medium test tube. You will use an old, stained test tube for this
procedure. Holding the test tube with the test tube holder, SLOWLY heat the test tube until a significant change is observable. Place
your test tube in a medium beaker to cool. You may place your sample in the fume hood if the change is significant.
10. After the test tube has cooled dump the solid water into the trash and clean the test tube.
Procedure G
11. Think back to the Sand and Salt Separation lab. Record what the salt water looked like before you heated it and record what the
sample of salt water looked like after you heated it.
12. After the conclusion of Procedures A-G return your supplies to the lab table. Be sure to wash your hands after returning your
equipment!
Analysis Answer in complete thoughts for credit!
1. Identify the procedures where physical changes occurred. Be sure to describe the elements and compounds used not the letter of
the procedure. Explain how you determined each was a physical change. You may create a data table to answer this question.
2. Identify the procedures where chemical changes occurred. Be sure to describe the elements and compounds used not the letter of
the procedure. Explain how you determined each was a chemical change. You may create a data table to answer this question.
3. If color change could be evidence of both a chemical and physical change how could you determine which type of change were
happening in an experiment?
Conclusion
Summarize physical and chemical changes. Be sure to describe how you can determine if a physical or chemical change has occurred.