1. Matter & Bonding Lesson # 6
Synthesis & Decomposition

2. Synthesis
A synthesis reaction is the combination of small atoms/molecules into larger molecules.
It is also called a combination reaction.
General Formula: A + B → AB
When there is only ONE product, you can tell it is synthesis.

3. Synthesis (continued)
Visuals: heat or light given off as the reactants come together
Real-Life Examples: metals burning in oxygen to form a coating called an oxide (iron oxide is rust), sulfur compounds reacting with water to form acid rain (sulfuric acid)

4. Examples Example: 2 H2 + O2 → 2 H2O Example: H2O + CO2 → H2CO3
*Note that although synthesis reactions can involve elements or compounds, metals or non-metals, the only ones you will have to predict the products for will be between a metal and a non-metal. In this case, they create an ionic compound.

5. Practice
Sodium + Chlorine →
Magnesium + Phosphorus →

6. Decomposition
A decomposition reaction is the splitting of a large molecule into elements or smaller molecules.
General Formula: AB → A + B
When only ONE reactant exists, it must be decomposition.

7. Decomposition (continued)
Visuals: Usually these reactions involve heat, pressure, or a catalyst to force the reaction to occur, and if a gas is one of the products, you may see the gas being given off.
Real-Life Examples: Breaking apart water or methane (CH4) to create hydrogen as fuel for vehicles.

8. Examples Example: 2 H2O → 2 H2 + O2 Example: 2 NI3 → N2 + 3 I2
*Note that although decomposition reactions can involve elements or compounds, metals or non-metals, the only ones you will have to predict the products for will be ionic or molecular compounds. Ionic compounds will form a metal and a non-metal, and molecular compounds will form two non-metals.

9. Practice
Potassium Nitride →
Diphosphorus pentoxide →