Combination Reaction:

A combination reaction occurs when two or more reactants combine to form a single product. An example of a combination reaction is the formation of water from hydrogen and oxygen gases:

• 2H₂ + O₂ → 2H₂O

Decomposition Reaction:

A decomposition reaction is the opposite of a combination reaction, where a single compound breaks down into two or more simpler products. An example of a decomposition reaction is the breakdown of calcium carbonate into calcium oxide and carbon dioxide:

• CaCO₃ → CaO + CO₂

Combination and decomposition reactions are fundamental concepts in chemistry that illustrate how substances interact. Let's break down each type for clarity.

Combination Reactions

A combination reaction occurs when two or more substances unite to form a single product. This type of reaction is essential in various chemical processes.

• Example: The formation of water is a classic illustration. When hydrogen gas (H₂) reacts with oxygen gas (O₂), they combine to produce water (H₂O).
• Equation: 2H₂ + O₂ → 2H₂O

Key Characteristics

In combination reactions:

• Multiple reactants come together.
• Only one product is formed.

Decomposition Reactions

In contrast, a decomposition reaction involves a single compound breaking down into two or more simpler substances. This process is crucial in various natural and industrial applications.

• Example: The breakdown of calcium carbonate (CaCO₃) into calcium oxide (CaO) and carbon dioxide (CO₂) is a well-known decomposition reaction.
• Equation: CaCO₃ → CaO + CO₂

Key Characteristics

For decomposition reactions:

• One reactant is involved.
• Multiple products are generated.

Understanding these reactions helps in grasping the basics of chemical transformations and their applications in real life.