NAME:__________________________________________DATE:____________________STATION:__________
LAB TEST
“Physical and Chemical Changes”
PURPOSE:
To observe physical and chemical changes in matter
MATERIALS:
3 medium test tubes
test tube holder
crucible tongs
spatula (5)
iron filings (Fe)
sucrose (C12H22O11)
sand
1 small test tube
scissors
watch glass
Bunsen burner
sodium bicarbonate (NaHCO3)
sodium chloride (NaCl)
matches
test tube rack
1 sheet of paper
magnet
sunglasses
6M hydrochloric acid (HCl)
magnesium ribbon (Mg)
PROCEDURE: Part A
1.
Obtain a sheet of paper and cut it into six pieces. Label each with the name of one of the following
substances: magnesium, iron, sodium bicarbonate, sodium chloride, sucrose, and sand.
2.
Obtain a 1-cm piece of magnesium ribbon from the labeled canister at your station. Place it on the
appropriately labeled paper. Using labeled scoops, transfer a small, pea-sized sample of each of the
other substances to the remaining papers.
3.
Classify each substance as an element, compound, or mixture, and record this information in the data
table at the end of this section.
4.
Examine each substance carefully. CAUTION: Never taste any of the substances. Record your
observations of the physical appearance of each substance in the data table. You must make at least
three observations about each substance.
5.
Obtain a magnet in a plastic bag. Do not remove the magnet from the bag! Test the effect of a
magnet on each substance by passing the magnet under the paper. Record the observations.
6.
Combine the samples of iron filings, sodium chloride (salt – NaCl), and sand onto a clean piece of white
paper. Mix the samples thoroughly. Move a magnet under the paper below the mixture and examine
it again. Record your observations:
___________________________________________________________________________________
____________________________________________________________________________________
Mixing iron filings, salt, and sand is a (physical / chemical) change. Explain. ______________________
____________________________________________________________________________________
DATA:
SUBSTANCE
Element, Compound,
or Mixture?
Physical Appearance
Magnetic?
Iron Filings
Fe
Sodium Bicarbonate
NaHCO3
(Baking Soda)
Sodium Chloride
NaCl
(Salt)
Sucrose
C12H22O11
(Sugar)
Sand
Magnesium
Mg
PROCEDURE: Part B
1.
Place a watch glass on the laboratory bench close to a Bunsen burner. Light the burner. Obtain a 5-cm
piece of magnesium from the labeled canister. Put on sunglasses to protect your eyes! Use crucible
tongs to grasp the strip and hold it in the burner flame until the magnesium ignites. CAUTION: Do not
look directly at the burning magnesium. Its flame is very bright and can damage your eyes. Do not
inhale the fumes. Keep the burning magnesium at arms length at all times, and hold it over the
watch glass. Record our observations:
___________________________________________________
____________________________________________________________________________________
Compare the appearance of the combustion product (the material that falls into the watch glass after
burning) with that of the original magnesium.
_______________________________________________
____________________________________________________________________________________
Cutting the magnesium is a (physical / chemical) change. Explain. ______________________________
____________________________________________________________________________________
Burning the magnesium is a (physical / chemical) change. Explain.______________________________
____________________________________________________________________________________
2.
Obtain a 1-cm piece of magnesium from the labeled container and place it into clean, dry medium test
tube. Add 10 drops of 6 M hydrochloric acid (HCl) to the test tube. CAUTION: Hydrochloric acid is
corrosive to the skin. Feel the bottom of the test tube. Record your observations.
___________________________________________________________________________________
___________________________________________________________________________________
Mixing the magnesium with hydrochloric acid is a (physical / chemical) change. Explain.___________
____________________________________________________________________________________
3.
Transfer a small scoop of sodium bicarbonate (baking soda – NaHCO3) to two clean, dry medium test
tubes. Fill one of the test tubes half full with water. Add 5 drops of 6 M hydrochloric acid to the other.
Compare the results:
____________________________________________________________________________________
____________________________________________________________________________________
Dissolving sodium bicarbonate in water is a (physical / chemical) change. Explain. _________________
____________________________________________________________________________________
Reacting sodium bicarbonate with hydrochloric acid is a (physical / chemical) change. Explain. ______
____________________________________________________________________________________
4.
Add two scoops of sucrose (sugar – C12H22O11) to a small test tube. Hold the test tube with a test tube
holder and heat it gently in the burner flame. Watch the tube carefully for changes. CAUTION: When
heating a test tube, never point the mouth of the tube at yourself or anyone else. Never check for
odor from a tube while it is being heated. Remove the test tube from the flame and set it carefully in
the test tube rack. Compare the product of the reaction to the original sucrose.
____________________________________________________________________________________
____________________________________________________________________________________
Burning sucrose is a (physical / chemical) change. Explain. ____________________________________
____________________________________________________________________________________
OPEN-ENDED (FREE) RESPONSE:
A mixture of salt, sand, and iron filings is found in the store room. Using
evidence from this lab, as well as our discussions in class, how would you separate these substances into three
separate containers? Be sure to describe how you would obtain each of the three substances.
NAME:__________________________________________DATE:____________________STATION:__________
PRE-LAB
“Physical and Chemical Changes”
Read through the lab and answer the following questions:
1.
What six substances are to be tested in this lab?
2.
What procedure should you use in this lab when testing a substance to see if it is magnetic?
3.
What special precautions should you use when burning magnesium?
4.
What property of hydrochloric acid makes its use of particular concern in any laboratory situation?
5.
What method should you use when testing the odor of a material? (See your safety rules)
When should the odor of materials never be tested?
6.
What special precaution should you always use when heating substances in a test tube?
7.
What are six indications of a chemical change? (See your notes)
a.
_____________________________________________________________
b.
_____________________________________________________________
c.
_____________________________________________________________
d.
_____________________________________________________________
e.
_____________________________________________________________
f.
_____________________________________________________________