BalancingChemical Equations

REVIEW:

The starting materials are called reactants

The ending materials are called products

Reactants yield Products

Why we balance equations:

The Law of Conservation of Matter states that matter can not be created or destroyed.

So we need to have the same number of atoms before the reaction as after the reaction.

The number of reactant atoms = product atoms.

How to balance equations:Step 1:• Write the equation and count the number of each

atom, both reactant and product. • Put this information in a before and after chart.

CH4 + O2 = CO2 + H2O

Carbon has 1 on each sideHydrogen is unbalanced, 4 and 2Oxygen is unbalanced, 2 and 3

Step 2:Place a coefficient in front of the molecule to balance the equation

CH4 + 2O2 = CO2 + 2H2O

Step 2:Place a coefficient in front of the molecule to balance the equation

CH4 + 2O2 = CO2 + 2H2O

C = 1 C = 1H = 4 H = 4O = 4 O = 4

C3H8 + O2 → H2 O + CO2

C=3 C=1H=8 H=2O=2 O=3

C3H8 + O2 → H2 O + CO2

P4 O10 + H2 O → H3 PO4

P=4 P=1O=11 O=4H=2 H=3

P4 O10 + H2 O → H3 PO4