Observing Chemical Reactions (Teacher Notes)
PSI Chemistry
Objective:
The goals of this lab are to:
 Observe a number chemical reactions.
 Outline the indications that a chemical reaction has occurred while observing the chemical
reactions in this lab.
 Outline those changes in properties or changes in energy that result from the chemical
reactions you observe.
 Differentiate between a physical and a chemical change.
Background:
During a chemical change (called a chemical reaction) a substance or substances are transformed
into a chemically different substances. Chemical changes can be dramatic or subtle but in all cases
there is a set of indications that a chemical reaction has occurred. Also, in all cases there is a change
in the properties of the substance(s) you began with, the reactant(s) as they are transformed into the
substance(s) that are created at the end of the reaction, the products.
Materials:
 Acetate sheet
 Reaction Grid (Found on the final page of this document).
 1 M hydrochloric acid
 0.1 M copper (II) sulfate
 0.1 M potassium iodide
 0.1 M lead (II) nitrate
 Mossy zinc metal or zinc chips
 Beral pipettes
 goggles
 aprons
Preparation (if possible before class):
This lab is best completed with teams of no more than 3 students to ensure all students have an
opportunity to mix the chemicals and can clearly make and note observations. All solutions should be
pre-made and stored in glass or plastic bottles with dropper tops. 30 mL Amber glass bottles with
dropper tops can be purchased from Flinn Scientific. The solutions you make in this lab can be
utilized later in completing labs in the Ionic bonding and Ionic compounds, Chemical reactions and
Stoichiometry units.
Timing: This is a one period lab. Approximate timing is as follows:
 5 minutes to setup acetate sheet and reaction grid and for students to collect and become
familiar with the solutions.
 20 minutes to collect and record data
 10 minutes for class discussion and conclusion
Safety Concerns:
Instructors should familiarize students with the location of laboratory safety equipment. Students
should know where to find running water, an eyewash and shower, an emergency blanket and the fire
extinguisher before beginning the lab.
Students should also be instructed on the following safety guidelines before beginning the lab:
Always wear your goggles and aprons while completing this lab.
Also wear your goggles and aprons when you're near someone working with chemicals.
Familiarize yourself with the location of the eyewash and the emergency shower in the room. If
you get any chemicals in your eye, use the eyewash.
If any of the chemicals come in contact with your skin rinse them off immediately with lots of
water and let the instructor know what you spilled --- on your way to rinsing them off.
Never mix chemicals that you haven't been told to mix.
Tell the instructor of any accidents immediately.
Keep food and drinks out of the laboratory work area.
Anticipated Results:
A
B
C
D
E
HCl
CuSO4
KI
Pb(NO3)2
Zinc
The students
may see a
cloudy blue
solution form
as sulfuric
acid is
produced.
No reaction.
No reaction.
H2 gas evolves
and heat is
released. Zinc
is more active
and displaces
H2..
A
A cloudy
Copper is
white ppt.
displaced from
PbSO4 forms. solution and
collects on the
zinc. The blue
copper sulfate
solution slowly
becomes
clearer. Zinc is
more active.
B
A bright
yellow ppt.
Pb2 forms.
C
No reaction.
No reaction.
Potassium is
more reactive.
HCl
CuSO4
KI
Lead is
displaced from
solution and
collects on the
zinc. Zinc is
more active.
D
Pb(NO3)2
E
Zinc
Follow Up (next day):
 Students could be introduced to Dalton's Atomic Theory if this has not been covered. This lab
relates directly to his postulates that in chemical reactions matter is not created or destroyed
but is rearranged to form new substances.
 Intensive and extensive properties of matter can also be discussed.
Presentation and Handout Materials
Smart Notebook class presentation and lab handouts for this lab are available through teacher access
to the PSI Chemistry website in the Atomic Structure Unit.