States of Matter

STATES OF MATTER

Matter is literally everything around you — your phone, the air you're breathing, your food, even the Lagos heat 😭.
But no matter how different they look, all forms of matter exist in three main states:

🔹 Solid
🔹 Liquid
🔹 Gas

(Some textbooks add Plasma, but for WAEC/JAMB, these three are king.)

Let’s break them down properly.

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1️⃣ What Is Matter?

Matter is anything that has mass and occupies space.
Everything you can touch, smell, see, or even feel is matter.

Matter is made up of tiny particles (atoms, ions, molecules) that are constantly moving — and how they move determines the state of matter.

This leads us to the Kinetic Theory of Matter.

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2️⃣ Kinetic Theory of Matter (Very Important)

The theory says:

• All matter is made of small particles.

• These particles are in constant motion.

• The strength of attraction between particles differs from one state to another.

• The energy of the particles determines whether matter is solid, liquid, or gas.

WAEC/JAMB LOVES this part.

Now let’s see how this affects each state.

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3️⃣ SOLID STATE

Particle Arrangement

• Tightly packed

• Arranged in a fixed pattern

• Very strong forces holding them together

Particle Motion

• They don’t move freely

• Only vibrate about fixed positions

Properties of Solids

• Fixed shape

• Fixed volume

• Cannot be compressed

• High density

• Do not flow

Examples

• Ice

• Salt

• Stone

• Metals

Why they behave this way

Particles have very low kinetic energy → they can’t roam around → everything stays rigid and fixed.

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4️⃣ LIQUID STATE

Particle Arrangement

• Close together but not in fixed positions

• Weaker forces than solids

• Particles can slide over each other

Particle Motion

• Move more freely than in solids

• Still not able to escape completely

Properties of Liquids

• No fixed shape (takes the shape of the container)

• Fixed volume

• Cannot be compressed easily

• Flow easily

• Medium density

Examples

• Water

• Milk

• Oil

• Alcohol

Why they behave this way

Particles have more kinetic energy than in solids → they can move around but stay close.

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5️⃣ GASEOUS STATE

Particle Arrangement

• Very far apart

• Forces of attraction are extremely weak

Particle Motion

• Move randomly and rapidly in all directions

• High kinetic energy

Properties of Gases

• No fixed shape

• No fixed volume

• Highly compressible

• Very low density

• Can diffuse quickly

• Exert pressure on container walls

Examples

• Oxygen

• Nitrogen

• Water vapour

• Carbon dioxide

Why they behave this way

Particles have very high kinetic energy, so they spread out and fill any space available.

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6️⃣ CHANGE OF STATE (VERY IMPORTANT)

Matter can change from one state to another when heat is added or removed.

🔹 Melting — Solid → Liquid

(Heat absorbed)

🔹 Freezing — Liquid → Solid

(Heat released)

🔹 Boiling/Evaporation — Liquid → Gas

(Heat absorbed)

🔹 Condensation — Gas → Liquid

(Heat released)

🔹 Sublimation — Solid → Gas directly

Examples:

• Iodine

• Camphor

• Dry ice (solid CO₂)

🔹 Deposition — Gas → Solid

(The reverse of sublimation)

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7️⃣ REAL-LIFE APPLICATIONS

• Refrigerators use evaporation & condensation.

• LPG in cylinders is gas compressed into liquid.

• Clouds form through condensation.

• Ice melting is the simplest example of change of state.

• Dry ice used in parties is sublimation in real time.

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8️⃣ DIAGRAM (Text-Friendly Version)

Solid ----(melting)----> Liquid ----(vaporization)----> Gas ^ | | | v v (freezing) (condensation) (deposition)

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9️⃣ WAEC/JAMB Likely Questions

1. Compare the particle arrangement in solids, liquids, and gases.

2. Explain why gases are easily compressible.

3. State three differences between evaporation and boiling.

4. Define sublimation and give two examples.

5. Why do liquids have no fixed shape but have fixed volume?