1. 📌 Essentials

• Matter: occupies space, has mass, obeys conservation law.
• States of matter: solid, liquid, gas; characterized by particle arrangement and movement.
• Density: mass per unit volume; key for identifying substances.
• Physical properties: color, melting point, density; chemical properties: reactivity flammability.
• Phase changes: melting, freezing vaporization, condensation, sublimation, deposition.
• Gas laws: $PV = nRT$; relate pressure, volume, temperature, moles.
• Motion: described by distance, displacement, speed, velocity, acceleration.
• Graphs: slope indicates speed; flat line = no movement.
• Separation techniques: filtration, distillation.
• Physical vs chemical reactions: energy transfer, phase change vs chemical change.

2. 🧩 Key Structures & Components

• Atoms — basic units of elements, building blocks of matter.
• Elements — pure substances with one type of atom.
• Compounds — chemical combinations of elements.
• Mixtures — combinations of substances; homogeneous or heterogeneous.
• Particles — atoms, molecules, ions.
• States of matter — solids, liquids, gases.
• Gas particles — far apart, move freely.
• Phase change points — melting point, boiling point.
• Thermal energy — influences state changes.
• Gas laws components — pressure (P), volume (V), temperature (T), amount (n).

3. 🔬 Functions, Mechanisms & Relationships