Matter & Bonding Lesson # 6 Synthesis & Decomposition

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.

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)

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.

Practice Sodium + Chlorine → Magnesium + Phosphorus →

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.

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.

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.

Practice Potassium Nitride → Diphosphorus pentoxide →