Balancing Chemical Equations

Reactants yield Products 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 CH4 + 2O2 = CO2 + 2H2O Carbon has 1 on each side Hydrogen is unbalanced, 4 and 2 Oxygen 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 = 1 H = 4 H = 4 O = 4 O = 4

C3H8 + O2 → H2 O + CO2 C3H8 + O2 → H2 O + CO2 C=3 C=1 H=8 H=2 O=2 O=3 C3H8 + O2 → H2 O + CO2

P4 O10 + H2 O → H3 PO4 P=4 P=1 O=11 O=4 H=2 H=3 P4 O10 + H2 O → H3 PO4