Download Balancing Chemical Equations Using Models

Name: ____________________________________ Date: _______ Period: ____
Balancing Chemical Equations Using Models
Objective
Use models as a means for balancing chemical equations.
Materials
For each group of 4 students:
• Cup of Skittles
• 2 Paper Plates
Procedure
1. Label one plate reactants and the other products, to represent each side of a chemical
equation. Use at least four different colors of skittles (representing atoms of different
elements) to make models of the substances in each equation below.
4 Skittles
2. Choose one color to represent an element in the following chemical reaction.
3. To create a compound, put the correct color skittles together to represent a bond
between the atoms.
Ex: ___HCl + ____NaOH
____NaCl + ____H2O
Na
H
+
NaOH
Cl
HCl
O
NaCl
+
H2O
4. Count the number of atoms you have total for your products and for your reactants,
before you attempt to balance the equation. Look for the same colors on the products
and reactants.
Reactants
Products
Before Balancing After Balancing
Before Balancing After Balancing
Na
O
H
Cl
1
1
2
1
Na
O
H
Cl
1
1
2
1
Name: ____________________________________ Date: _______ Period: ____
5. Determine if you need to balance the equation by adding coefficients, by comparing
the numbers for each atom on the reactant side with the product side.
___HCl + ____NaOH
____NaCl + ____H2O
Reactants
Before Balancing After Balancing
Na
O
H
Cl
1
1
2
1
Products
Before Balancing After Balancing
Na
O
H
Cl
1
1
2
1
6. Then add any coefficients if they are needed, and count how many atoms we now
have.
___HCl + ____NaOH
____NaCl + ____H2O
For our example we have the same number of each atom for both products and
reactants, we do not need to add any coefficients to balance the equation.
Reactants
Before Balancing After Balancing
Na
O
H
Cl
1
1
2
1
1
1
2
1
Products
Before Balancing After Balancing
Na
O
H
Cl
1
1
2
1
1
1
2
1
Task:
For each reaction below, use your models to determine the products needed (if not already
indicated), and then balance the equation. You will also need to indicate what kind of
reaction is occurring: single replacement, double replacement, combustion, synthesis, or
decomposition.
a. ___H2 + ____Cl2
____HCl
Reactants
Products
Before Balancing After Balancing
Before Balancing After Balancing
Name: ____________________________________ Date: _______ Period: ____
b. ___ Mg + ___O2
___MgO
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
c. ___C2H6 +___ O2
___CO2 + ___H2O
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
d. ___KI + ___Br2
___KBr + ___I2
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
e. ___H2CO3
___CO2 + ___H2O
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
Name: ____________________________________ Date: _______ Period: ____
f. ___Ca + ___H2O
___Ca(OH)2 + ___H2
Reactants
Before
After Balancing
Balancing
Products
Before Balancing After Balancing
g. ___KClO3
___KCl + ___O2
Reactants
Before
After Balancing
Balancing
Products
Before Balancing After Balancing
h. ___CH4 + ___O2
___CO2 + ___H2O
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
For the next four reactions you will need to determine what the products will be and
balance the equation.
i. ___Zn + ___HCl
Reactants
Products
Before Balancing After Balancing
Before Balancing After Balancing
Name: ____________________________________ Date: _______ Period: ____
j. ___ C2H6 + ___ O2
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
k. ___C3H8 + ___O2
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
l. ___BaO + ___H2O
Reactants
Before Balancing After Balancing
Products
Before Balancing After Balancing
Analysis
1. What side of the equation are the reactants found? products?
2. Why do we balance chemical equations?
3. Why do we need the same amount of each atom on both the product and
reactants sides?
4. Why can't the subscripts be changed?