States of Matter Exploration

Name:

Date:

📚 Part 1: Multiple Choice (Choose one)

1. Which state of matter has a fixed shape and fixed volume?

Solid

Liquid

Gas

Plasma

2. At 25°C a material flows and takes the shape of its container while maintaining volume. What is its state?

Solid

Liquid

Gas

Supercritical fluid

3. Which process describes a solid changing directly into a gas (skipping the liquid phase)?

Condensation

Sublimation

Deposition

Melting

4. Which term correctly names the phase change from gas directly to solid?

Freezing

Deposition

Ionisation

Evaporation

✏️ Part 2: Short Answers and Reasoning

5. In two clear sentences, explain the difference between evaporation and boiling.

6. Describe, in bullet form, how particle arrangement and movement differ in solids, liquids and gases (one line each).

7. A sealed beaker contains pure water ice at −10°C. The beaker warms slowly to +10°C. List the phase changes that occur in order and give the approximate temperature at which each change starts.

8. Dry ice (solid CO₂) sublimates at about −78°C at atmospheric pressure. Explain in two sentences why dry ice left at 20°C turns to gas instead of liquid.

🔬 Part 3: Extension — Diagram & Answers

9. Draw three small labelled particle diagrams: solid, liquid, gas. Indicate relative particle spacing and arrows for movement. (Use the box below.)

Answer Key (check your work). Brief explanations are provided for advanced understanding.

1. Solid — particles closely packed in fixed positions; strong intermolecular forces. 2. Liquid — flows, fixed volume, particles close but able to slide past each other. 3. Sublimation — solid → gas (examples: dry ice, iodine). Energy input overcomes lattice without forming liquid. 4. Deposition — gas → solid (examples: frost forming on a cold surface). 5. Evaporation occurs at the surface at temperatures below the boiling point; boiling is a bulk process with vapour bubbles forming at the boiling temperature. Evaporation can occur at any temperature; boiling requires sufficient vapour pressure equal to external pressure. 6. Solid: particles tightly packed, vibrate in place. Liquid: particles close, translational movement and rearrangement. Gas: particles far apart, high-speed random motion. 7. −10°C → 0°C: solid (ice). At 0°C melting begins (solid → liquid). At 100°C (at 1 atm) liquid → gas (boiling). (Note: in a sealed beaker pressure may change, altering boiling point.) 8. CO₂ at 20°C cannot exist as a liquid at atmospheric pressure because its triple point is at higher pressure; heating provides enough energy for solid→gas transition without passing through a stable liquid phase.