The Three States of Matter Grade 5 - Answers | Slides Chemistry ... - Free Printable

The image you've uploaded is a completed answer key for a Grade 5 science handout titled "The Three States of Matter", created by Science North. It covers the properties and changes in matter, specifically focusing on solids, liquids, and gases.

Below is a detailed explanation of each question and its answer, along with an analysis of the scientific concepts involved:

---

1. Draw the particles of the three different states of matter (solid, liquid, and gas).

Answer:
- Solid: Particles are tightly packed in a fixed, orderly arrangement (like a lattice).
- Liquid: Particles are close together but can move past one another, filling the bottom of the container.
- Gas: Particles are far apart and move freely in all directions, filling the entire container.

✔ Explanation: This visual representation illustrates how particle arrangement and movement differ across states:
- In solids, strong intermolecular forces hold particles in place.
- In liquids, particles have more freedom to slide over each other.
- In gases, particles are highly energetic and spread out.

---

2. Provide an example of each state of matter discussed:

Answers:
- Solid: Chair
- Liquid: Juice
- Gas: Oxygen

✔ Explanation: These are common examples that help students relate abstract concepts to everyday life. Any real-world object fitting the state qualifies.

---

3. At what temperature does water turn into a solid?

Answer: 0°C

✔ Explanation: Water freezes at 0°C under standard atmospheric pressure. This is known as the freezing point. At this temperature, water molecules slow down enough to form a crystalline structure (ice).

---

4. At what temperature does water turn into a gas?

Answer: 100°C

✔ Explanation: Water boils at 100°C at sea level. This is the boiling point, where liquid water turns into steam (water vapor). The temperature may vary slightly with altitude due to changes in air pressure.

---

5. Based on experiments conducted, do you think all liquids turn to solid at the same temperature? Do you think all liquids turn to gas at the same temperature? Explain.

Answer: No — different liquids change states at different temperatures. For example, sugar crystals turned back into a solid even though it wasn’t below 0°C.

✔ Explanation: This highlights that each substance has unique physical properties:
- Freezing/melting points depend on molecular structure.
- For instance, butter melts around 32–35°C, while water freezes at 0°C.
- Similarly, alcohol evaporates at lower temperatures than water (e.g., ethanol boils at ~78°C).
- So, no universal temperature applies to all substances.

---

6. Once something is a solid, does it stay that way forever? Explain.

Answer: No — solids can change back into liquids or gases. Example: Ice cream (a solid) made from liquid cream can melt if left out too long.

✔ Explanation: This teaches the concept of reversibility in phase changes:
- Melting (solid → liquid): Occurs when heat is added.
- Evaporation/sublimation: Solids can directly become gases (e.g., dry ice).
- Real-life example: Ice cream melting shows that solids are not permanent unless kept cold.

---

7. Challenge Question: If sugar is a solid, then why does it take the shape of the container it is put in? What about salt or sand?

Answer: Sugar (and salt/sand) are still solids. Each crystal has fixed shape and volume, doesn't flow under shear stress, doesn't take the shape of the container, and is incompressible. However, many small solid grains moving together can act like a liquid (granular flow).

✔ Explanation: This is a great conceptual challenge that distinguishes between:
- True solids (fixed shape, rigid structure)
- Granular materials (collections of tiny solid particles)

Even though individual sugar crystals retain their shape, when poured, they behave like a flowing substance due to friction and gravity — this is called granular flow, which mimics fluid behavior but is not true liquidity.

> 💡 Think of pouring sand or sugar — it flows, but each grain remains a solid. This is why we say "sand behaves like a liquid" only in motion, not in nature.

---

✔ Summary of Key Concepts Covered:

| Concept | Explanation |
|-------|-------------|
| States of Matter | Solid, liquid, gas — defined by particle arrangement and movement |
| Phase Changes | Freezing, melting, boiling, evaporation — driven by temperature and energy |
| Temperature Dependence | Different substances have different freezing/boiling points |
| Reversibility | Changes in state are often reversible (e.g., freeze → thaw) |
| Granular Flow | Collections of small solids can flow like liquids without changing state |

---

🌟 Teaching Value:

This handout effectively uses:
- Visuals (particle diagrams)
- Real-world examples
- Critical thinking questions
- A challenge problem to deepen understanding

It aligns well with Grade 5 curriculum expectations for Ontario (or similar), emphasizing inquiry-based learning and scientific reasoning.

Let me know if you'd like a student-friendly version of this handout or a printable worksheet!