1. The Arithmetic of Equations
Section 9.1

2. Interpreting Chemical Equations
In terms of moles:
Example Equation:
2H2 + O2  2H2O
2 mol H2 +
1 mol O2 =
2 mol H2O

3. Interpreting Chemical Equations
In terms of particles:
You know that Avogradro’s Number relates particles and moles (6.02 x 1023 particles = 1 mole)
Example Equation:
2H O  2H2O
2 mol H2 x x 1023 particles +
1 mol
1 mol O2 x x 1023 particles =
1 mol
2 mol H2 x x 1023 particles
1 mol
1.204 x 1024 particles of H
6.02 x 1023 particles of O =
1.204 x 1024 particles of H2O

4. Interpreting Chemical Equations
In terms of mass:
1 mole = molar mass of element or compound
Example Equation:
2H O  2H2O
2 mol H2 x grams +
1 mol
1 mol O2 x grams =
1 mol
2 mol H2 x grams
1 mol
grams of H
grams of O =
grams of H2O

5. Interpreting Chemical Equations
In terms of volume:
1 mole = 22.4 Liters
Example Equation:
2H O  2H2O
2 mol H2 x L
1 mol
1 mol O2 x L =
1 mol
2 mol H2 x L
1 mol
44.8 L of H
22.4 L of O =
44.8 L of H2O

6. After reading Section 9.1, you should know:
How to balance a chemical equation
How to calculate particles, moles, volume and mass from a balanced equation