Balancing Equations!
Title your next journal page:
Balancing Equations!
You will use the whole page for this
activity
Making sense of balancing
chemical equations
Here we have magnesium metal before and
after burning in the same crucible. Which
one weighs more, the ashes or the metal?
When you learn to balance chemical
reactions, it becomes clear how the
Law of Conservation of Mass is one of
the greatest discoveries in chemistry
The purpose of this lesson is to
practice the technique of balancing
equations so that they obey the Law
of Conservation of Mass.
Write down this reaction on your
page:
___ Mg + ___ O2
____ MgO
Underneath the reaction write
this:
Atom Count:
Reactants Products
Balancing equations Step 1:
Do an atom count on both sides,
write this down under the formulas
Note: the picture
has paper clips,
we are using
beads – same
idea though!
What’s wrong with this?
The amounts are not the same, so it
is not balanced yet. How do we do
make it balanced?
Atom Count:
Reactants Products
1Mg 1Mg
2O 1O
Step 2: Crisscross the one set of
numbers that are not the same.
Making them the coefficients in the
equation.
You
crisscross
the 2 and
the 1
Step 3: After you crisscross, the next
step is to look at the number of
atoms you have on each side of the
equation
Step 4: You balance by placing
coefficients and not by changing
correct formulas
Balanced
equations have
the same number
of atoms on each
side of the
equations
The reason you balance
equations is to adhere to the Law
of Conservation of Mass
Balanced
equations have
the same number
of atoms on each
side of the
equations
Practice Time!
• Each group will get a set of beads.
• Use the beads to represent each element in
the formula.
• Go through the atom count for each reaction,
move the beads as needed