Name:____________________________
Chemical Reaction
Purpose:
To observe some typical chemical reactions, identify some of the products,
summarize the chemical reactions in terms of balanced equations and classify the
reactions as to type.
Introduction:
Chemical equations represent what transpires in a reaction in a net sense. For
example:
2KClO3 (s) →
2KCl (s)
+ 3O2 (g)
means that potassium chlorate decomposes on heating to yield potassium chloride and
oxygen gas. Before someone can write such an equation, the products must be
determined. How? Products are identified by their chemical and physical properties and
by various analyses. When you run the above reaction, it is obvious that a gas is given
off. But why do we know that it is oxygen and not chlorine? The gas given off is
colorless which fits oxygen since chlorine is a yellow-green gas. Chlorine also has an
irritating odor which is not true of oxygen. Finally oxygen gas supports combustion and
will make a glowing wood splint flame when it is introduced into a tube of oxygen gas.
Reactions are often classed into one of 4 categories.
A. Composition-In which two or more substances are combined to form a more
complex substance.
A + X →
AX
B. Decomposition-In which a complex substance breaks down to form two or more
simpler substances.
AX →
A + X
C. Single replacement-In which one substance is displaced from its compound by
another substance.
AX + B → BX + A
D. Double replacement/metathesis-in which the members of one compound switch
places with the members of another compound.
AX + BY → AY + BX
Procedure:
In each case, follow the directions, make observations about what happens, and
try to determine the balanced equation for the reaction by making it fit into one of the 4
categories above. In your observations be sure and tell what the reactant (s) looked like
before they were mixed or reacted as well as describing any changes. When picking the
types of reactions, circle the appropriate letter.
1. Add an eye dropper full of sodium iodide(aq) to an eye dropper full of lead (II)
nitrate(aq).
A. Observations:
B. Type of reaction:
C
D
SR
DR
C. Write the balanced equation for this reaction below.
2. In a test tube, add an eye dropper of Pb(NO3)2 (aq) to an eye dropper of HCl (aq).
A. Observations:
B. Type of reaction:
C
D
C. Write the balanced equation for this reaction below.
SR
DR
3. Add a small piece of zinc (s) to a test tube and then add an eyedropper of 6M HCl.
A. Observations:
B. Type of reaction:
C
D
SR
DR
C. Write the balanced equation for this reaction below.
4. Heat a sample of copper sulfate pentahydrate (CuSO4 ∙ 5H2O) in a large test tube.
Carefully observe the sides of the tube as you heat.
A. Observations:
B. Type of reaction:
C
D
SR
DR
C. Write the balanced equation for this reaction below.
5. Take a piece of magnesium metal about ½ inch long and hold it in a flame using
crucible tongs. DO NOT HOLD IT IN YOUR HANDS.
A. Observations:
B. Type of reaction:
C
D
C. Write the balanced equation for this reaction below.
SR
DR
6. Place a small piece of magnesium metal in a test tube and add a dropper of 6M HCl.
A. Observations:
B. Type of reaction:
C
D
SR
DR
C. Write the balanced equation for this reaction below.
7. Before doing the next one, note that hydrogen carbonate is unstable. H2CO3
decomposes spontaneously to give H2O and CO2 (g).
Add an eyedropper of 6M HCl to a piece of calcium carbonate in a test tube.
A. Observations:
B. Type of reaction:
(Initial reaction)
Type of reaction:
(Second reaction)
C
D
SR
DR
C
D
SR
DR
C. Write the balanced equation for the reactions. These should be two separate
Equations.