Understanding Matter: Physical and Chemical Changes

📋 Course Outline

1. Physical and Chemical Changes
2. Particle Behavior in States
3. Reversible vs Irreversible
4. Changes in State
5. Mixing and Dissolving
6. Particle Arrangement
7. Chemical Reaction Signs
8. Chemical Equations
9. Energy in Reactions
10. Particle Model Explanation

📖 1. Physical and Chemical Changes

🔑 Key Concepts & Definitions

• Physical change: A change where the form or appearance of a substance alters, but its chemical composition remains the same. No new substances are formed (see section 2.3).
• Chemical change: A process that results in the formation of one or more new substances with different properties from the original substances, often involving energy changes and signs like colour change or gas production.
• New substance formation: The creation of a different chemical substance during a chemical change, characterized by altered properties and often irreversible.
• Observation of changes in chocolate and cacao beans: During chocolate making, physical changes such as melting and crushing cacao beans occur, while overheating chocolate causes chemical changes like burning, which produce new substances.
• Physical and chemical change examples in food context: Melting chocolate (physical), crushing cacao beans (physical), burning chocolate (chemical), baking a cake (chemical), dissolving salt in water (physical).

📝 Essential Points