Educational worksheet for students to practice distinguishing between physical and chemical properties and changes in matter.

Let's go through the worksheet step by step and solve each section with explanations.

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i. Identify if the following are chemical or physical properties

Definitions:
- Physical Property: A characteristic that can be observed or measured without changing the substance’s chemical identity (e.g., color, density, melting point).
- Chemical Property: A characteristic that describes how a substance interacts with other substances to form new substances (e.g., flammability, reactivity).

1. Iron reacts with oxygen and forms rust.
→ This involves a reaction forming a new substance (rust = iron oxide).
✔ Chemical property

2. The boiling point of water is 100 °C.
→ Boiling point is a physical change (liquid to gas), no new substance formed.
✔ Physical property

3. Baking soda reacts with vinegar.
→ Produces carbon dioxide gas; a chemical reaction occurs.
✔ Chemical property

4. The gas is flammable.
→ Flammability refers to ability to burn (react with oxygen).
✔ Chemical property

5. Oxygen is a gas.
→ Describes state of matter (physical state).
✔ Physical property

6. Argon is not very reactive.
→ Reactivity is a chemical behavior.
✔ Chemical property

7. Nitrogen is a colorless gas.
→ Color and state are physical characteristics.
✔ Physical property

8. The silver spoons were tarnished and turned dark.
→ Tarnishing is a chemical reaction (silver reacts with sulfur).
✔ Chemical property

9. The piece of metal is magnetic.
→ Magnetism is a physical property.
✔ Physical property

10. A student's shirt suddenly bursts into flames.
→ Combustion is a chemical change. The flammability of fabric is a chemical property.
✔ Chemical property

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ii. Classify as Chemical Change (CC), Chemical Property (CP), Physical Change (PC), or Physical Property (PP)

| Item | Classification | Explanation |
|------|----------------|-----------|
| 1. Heat conductivity | PP | Ability to conduct heat — physical property |
| 2. Silver tarnishing | CC | Reaction with sulfur in air → new compound |
| 3. Sublimation | PC | Solid → gas without liquid phase; physical change |
| 4. Magnetizing steel | PC | Alignment of domains; no new substance |
| 5. Shortening melting | PC | Solid → liquid; physical change |
| 6. Length of a metal object | PP | Measurable size — physical property |
| 7. Exploding dynamite | CC | Rapid chemical reaction producing gases |
| 8. Combustible | CP | Ability to burn — chemical property |
| 9. Water freezing | PC | Liquid → solid; physical change |
| 10. Wood burning | CC | Oxidation produces ash, CO₂, etc. |
| 11. Acid resistance | CP | How it reacts with acid — chemical property |
| 12. Brittleness | PP | Physical behavior under stress |
| 13. Milk souring | CC | Bacteria produce lactic acid; new substances |
| 14. Bread baking | CC | Maillard reaction, starch gelatinization, new compounds |

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iii. True (T) or False (F)

1. Changing the size and shapes of pieces of wood would be a chemical change.
→ Cutting or shaping wood doesn't alter its chemical composition.
✘ False (F)

2. In a physical change, the makeup of matter is changed.
→ In physical changes, composition remains same.
✘ False (F)

3. Evaporation occurs when liquid water changes into a gas.
→ Yes, this is the definition of evaporation.
✔ True (T)

4. Evaporation is a physical change.
→ No new substance formed; just phase change.
✔ True (T)

5. Burning wood is a physical change.
→ Burning involves combustion (chemical reaction), produces ash, CO₂, etc.
✘ False (F)

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✔ Final Answers:

#### Section i:
1. Chemical
2. Physical
3. Chemical
4. Chemical
5. Physical
6. Chemical
7. Physical
8. Chemical
9. Physical
10. Chemical

#### Section ii:
1. PP
2. CC
3. PC
4. PC
5. PC
6. PP
7. CC
8. CP
9. PC
10. CC
11. CP
12. PP
13. CC
14. CC

#### Section iii:
1. F
2. F
3. T
4. T
5. F

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