Educational worksheet for students to learn and identify physical and chemical properties and changes through examples and definitions.

Let's solve this step by step, using the definitions provided in the worksheet.

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Part 1: Identify as Chemical (C) or Physical (P) Property

Definitions:
- Physical Property: Observed with senses, determined without destroying matter.
- Chemical Property: Indicates how a substance reacts with something else; results in a new substance after reaction.

#### Answers:
1. blue color → P (observed with sight, no change in substance)
2. density → P (measurable without changing substance)
3. flammability (burns) → C (involves combustion, creates new substances)
4. solubility (dissolves) → P (dissolving doesn't change chemical identity)
5. reacts with acid → C (chemical reaction occurs)
6. supports combustion → C (indicates reactivity, like oxygen)
7. sour taste → P (taste is a sensory observation, not a reaction)
8. melting point → P (change of state, no new substance)
9. reacts with water → C (chemical reaction forms new substances)
10. hardness → P (physical characteristic)
11. boiling point → P (change of state)
12. luster → P (appearance, visual property)
13. odor → P (sensory, observed without changing substance)
14. reacts with air → C (e.g., rusting, oxidation)

✔ Answers:
1. P
2. P
3. C
4. P
5. C
6. C
7. P
8. P
9. C
10. P
11. P
12. P
13. P
14. C

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Part 2: Identify as Physical (P) or Chemical (C) Change

Definitions:
- Physical Change: Change in size, shape, or state; no new substance formed.
- Chemical Change: New substance formed; physical and chemical properties change.

#### Answers:
1. NaCl dissolves in water → P (dissolving is physical; salt can be recovered)
2. Ag (Silver) tarnishes → C (forms silver sulfide, new substance)
3. An apple is cut → P (only shape changed, no new substance)
4. Heat changes H₂O to steam → P (phase change, still water)
5. Baking soda reacts to vinegar → C (produces CO₂ gas, new substances)
6. Fe (Iron) rusts → C (iron oxide forms, new substance)
7. Alcohol evaporates → P (liquid to vapor, same substance)
8. Ice melts → P (solid to liquid, still water)
9. Milk sours → C (bacteria produce lactic acid, new substance)
10. Sugar dissolves in water → P (no chemical reaction)
11. Wood rots → C (decomposition, new substances form)
12. Pancakes cook → C (browning, Maillard reaction, new substances)
13. Grass grows → C (photosynthesis, new organic material)
14. A tire is inflated → P (air compressed, no chemical change)
15. Food is digested → C (broken down into new molecules)
16. Paper towel absorbs water → P (physical absorption, no chemical change)

✔ Answers:
1. P
2. C
3. P
4. P
5. C
6. C
7. P
8. P
9. C
10. P
11. C
12. C
13. C
14. P
15. C
16. P

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Part 3: Physical and Chemical Changes (Describe each)

We are to classify each situation as P (physical) or C (chemical).

1. An ice cube is placed in the sun. Later there is a puddle of water. Later still the puddle is gone.
→ Melting (ice → water), then evaporation (water → vapor). No new substances.
✔ P

2. Two chemicals are mixed together and a gas is produced.
→ Gas production indicates a chemical reaction.
✔ C

3. A bicycle changes color as it rusts.
→ Rusting is iron reacting with oxygen → iron oxide.
✔ C

4. A solid is crushed to a powder.
→ Only size changed; no new substance.
✔ P

5. Two substances are mixed and light is produced.
→ Light emission often indicates a chemical reaction (e.g., combustion).
✔ C

6. A piece of ice melts and reacts with sodium.
→ Ice melting = physical; but reaction with sodium = chemical.
→ The reaction part is key. So overall, C (since a chemical change occurred).
✔ C

7. Mixing salt and pepper.
→ No reaction; just a mixture. Can be separated.
✔ P

8. Chocolate syrup is dissolved in milk.
→ Dissolving is physical; no new substance formed.
✔ P

9. A marshmallow is toasted over a campfire.
→ Browing, charring, caramelization – all chemical changes.
✔ C

10. A marshmallow is cut in half.
→ Only shape changed; no new substance.
✔ P

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✔ Final Answers:

#### Part 1: Properties
1. P
2. P
3. C
4. P
5. C
6. C
7. P
8. P
9. C
10. P
11. P
12. P
13. P
14. C

#### Part 2: Changes
1. P
2. C
3. P
4. P
5. C
6. C
7. P
8. P
9. C
10. P
11. C
12. C
13. C
14. P
15. C
16. P

#### Part 3: Physical and Chemical Changes
1. P
2. C
3. C
4. P
5. C
6. C
7. P
8. P
9. C
10. P

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🔍 Summary of Key Concepts:

- Physical properties describe appearance or behavior without changing the substance’s identity.
- Chemical properties describe how a substance interacts/reacts with others to form new substances.
- Physical changes alter form or state but not composition.
- Chemical changes result in new substances with different properties.

This worksheet helps distinguish between observable traits and reactive behaviors, and between reversible vs irreversible transformations.