BALANCING CHEMICAL
EQUATIONS
Chapter 6.5
DAY 1 & 2
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Word equations or formula (skeleton)
equations need to be balanced.
The number of atoms of one element on
the reactant side of an equation must
equal the number of atoms of that same
element on the product side of an
equation.
LAW OF CONSERVATION OF MASS
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States: the total mass of atoms must be
the same on both sides of an equation.
Meaning –> the mass of the reactants
equals the mass of the products.
The same total number of each atom =
same total atomic mass
LETS BALANCE EQUATIONS
STEP 1 – Write the formula equation of the
reaction.
Example: CH4 + O2
CO2 + H2O
STEP 2 – Count the number of atoms of
each type on the reactants side and on
the products side
reactants
O–2
C–1
H–4
products
O-3
C-1
H–2
3) Multiply each of the formulas by an
appropriate coefficient to balance the
numbers of atoms
CH4 + 2 O2
CO2 + 2 H2O
4) Count atoms on each side to verify.
reactants
products
O–4
O-4
C–1
C-1
H–4
H–4
GROUP PRACTICE
1) hydrogen and oxygen produce water
2) calcium and chlorine make calcium
chloride
3) aluminum and oxygen produce aluminum
oxide
4) copper and iron(III) oxide make iron and
copper(I) oxide
HOMEWORK
PAGE 229 # 2, 3ade
Practice worksheet
BLM 6.5c Assignment