How do chemical reactions occur, and what are the different types?

 Chemical reactions happen when atoms or molecules interact, break old bonds, and form new ones, creating new substances. This involves a rearrangement of atoms and often a change in energy (heat, light, etc.).

🧪 Main Types of Chemical Reactions

Synthesis:

• Two substances combine → one product

A + B → AB

Decomposition:

• One substance breaks into parts
• AB → A + B
• Single Replacement:
• One element replaces another
• A + BC → AC + B

Double Replacement:

• Two compounds switch partners
• AB + CD → AD + CB

Combustion:

• Substance + oxygen → energy + CO₂ + H₂O

(e.g., burning fuels)