Worksheet for Grade 7 Science students to learn and classify physical and chemical properties of substances.

Let's solve this step by step.

We are asked to classify each of the 15 listed properties as either Physical Property or Chemical Property, based on the definitions provided:

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🔹 Physical Property:

- Can be observed or measured without changing the substance’s chemical identity.
- Examples: color, density, melting point, solubility, conductivity, etc.

🔹 Chemical Property:

- Describes how a substance interacts with other substances to form new substances.
- Involves a chemical change (a new substance is formed).
- Examples: flammability, reactivity with acids, rusting, etc.

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Now, let’s go through each item one by one:

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1. blue colour
→ Observed with eyes; no change in substance.
✔ Physical Property

2. density
→ Mass per unit volume; can be measured without changing the substance.
✔ Physical Property

3. flammability
→ Ability to burn (reacts with oxygen); produces new substances.
✔ Chemical Property

4. solubility
→ How well it dissolves in a solvent (e.g., sugar in water). No chemical change if it just dissolves (unless it reacts). But generally, solubility is considered a physical property because dissolution often doesn't involve chemical change (especially for things like salt in water).
✔ Physical Property

5. reacts with acid to form H₂
→ This involves a chemical reaction (e.g., zinc + HCl → ZnCl₂ + H₂). A new substance is formed.
✔ Chemical Property

6. supports combustion (burning)
→ This means it helps something burn (like oxygen). It indicates reactivity — a chemical behavior.
✔ Chemical Property

7. sour taste
→ Taste is a sensory observation; no chemical change occurs just from tasting. Though caution: tasting chemicals is unsafe, but the property itself is physical.
✔ Physical Property

8. melting point
→ Temperature at which solid turns to liquid; phase change, not chemical change.
✔ Physical Property

9. reacts with water to form a gas
→ A chemical reaction is occurring (e.g., sodium + water → hydrogen gas + sodium hydroxide). New substances form.
✔ Chemical Property

10. reacts with water
→ Similar to #9. If it forms a new substance, it's a chemical property. Even if not specified, "reacts" implies a chemical change.
✔ Chemical Property

11. hardness
→ Resistance to scratching; physical characteristic.
✔ Physical Property

12. boiling point
→ Temperature at which liquid turns to gas; physical change.
✔ Physical Property

13. breaks easily
→ Refers to brittleness; mechanical property, no chemical change.
✔ Physical Property

14. is magnetic
→ Magnetic attraction is a physical property.
✔ Physical Property

15. good conductor of heat and electricity
→ These are physical behaviors that do not alter the substance’s chemical identity.
✔ Physical Property

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✔ Final Answer Table:

| # | Property | Physical Property | Chemical Property |
|---|------------------------------------------|-------------------|-------------------|
| 1 | blue colour | ✔️ | |
| 2 | density | ✔️ | |
| 3 | flammability | | ✔️ |
| 4 | solubility | ✔️ | |
| 5 | reacts with acid to form H₂ | | ✔️ |
| 6 | supports combustion (burning) | | ✔️ |
| 7 | sour taste | ✔️ | |
| 8 | melting point | ✔️ | |
| 9 | reacts with water to form a gas | | ✔️ |
|10 | reacts with water | | ✔️ |
|11 | hardness | ✔️ | |
|12 | boiling point | ✔️ | |
|13 | breaks easily | ✔️ | |
|14 | is magnetic | ✔️ | |
|15 | good conductor of heat and electricity | ✔️ | |

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📌 Summary:

- Physical Properties: 1, 2, 4, 7, 8, 11, 12, 13, 14, 15 → 10 items
- Chemical Properties: 3, 5, 6, 9, 10 → 5 items

This classification helps distinguish between observable traits and reactive behaviors.