Students can use this worksheet to practice identifying physical versus chemical changes through various scenarios and statements.
Worksheet on physical and chemical changes featuring scenario identification and true/false questions for science students.
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Step-by-step solution for: Physical and Chemical Properties and Changes Worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Physical and Chemical Properties and Changes Worksheet
It looks like you've uploaded a worksheet titled "Physical and Chemical Changes" that contains two parts:
- Part A: A list of 10 scenarios, asking whether each is a physical change or a chemical change.
- Part B: A list of 10 statements, asking you to identify the type of change (physical or chemical) based on the description.
Since I can't view images directly, I’ll solve the problem based on the text you’ve provided. Let me go through each part step by step and explain the reasoning behind each answer.
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We are to determine if each process is a physical change or a chemical change.
> Physical change: The substance changes form, but not its chemical identity (no new substances formed).
> Chemical change: A new substance is formed; the molecular composition changes.
Let’s analyze each one:
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1. A chocolate bar is melted in the sun.
→ Melting is a phase change (solid → liquid), no new substance.
✔ Physical change
2. Two chemicals are mixed together and a gas is produced.
→ Gas production indicates a reaction (e.g., bubbles = CO₂). New substance formed.
✔ Chemical change
3. A piece of paper is torn into pieces.
→ Only size changed; no new substance.
✔ Physical change
4. A candle is lit.
→ Burning involves combustion (wax + oxygen → CO₂ + water).
✔ Chemical change
5. Two substances are mixed and light is produced.
→ Light emission often indicates a chemical reaction (e.g., glow sticks).
✔ Chemical change
6. A piece of iron rusts and turns brown.
→ Rusting is oxidation (iron + oxygen → iron oxide). New compound.
✔ Chemical change
7. Melting an ice cube.
→ Solid to liquid water — same molecule (H₂O).
✔ Physical change
8. Chlorophyll is dissolved in milk.
→ Dissolving is physical; no reaction (assuming it's just mixing).
✔ Physical change
9. A thermometer is broken over a sample.
→ Breaking glass is a physical change. No new substances.
✔ Physical change
10. A marshmallow is cut in half.
→ Size changed, not composition.
✔ Physical change
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Now we interpret each statement to determine if it describes a physical or chemical change.
1. Changing the physical state of a pure substance is a chemical change.
→ FALSE. Changing state (e.g., melting, boiling) is physical.
✘ Incorrect statement — this is not a chemical change.
2. The appearance of a new color means a chemical change has occurred.
→ Often true (e.g., rusting, burning). Color change can indicate a new substance.
✔ Chemical change
3. Evaporation is a physical change.
→ Liquid to gas — no new substance.
✔ Physical change
4. Dissolving a sugar cube in water is a physical change.
→ Sugar molecules remain intact; just dispersed. Can be reversed.
✔ Physical change
5. Combining hydrogen and oxygen to make water is a physical change.
→ This is a chemical reaction: 2H₂ + O₂ → 2H₂O. New substance.
✘ Incorrect — this is a chemical change
6. Burning wood is a physical change.
→ Wood burns → ash, CO₂, etc. New substances.
✘ Incorrect — this is a chemical change
7. Lighting a match is a chemical change.
→ Combustion occurs. Flame, heat, gases produced.
✔ Chemical change
8. Freezing steam results in ice.
→ Gas → solid. Still H₂O. Phase change.
✔ Physical change
9. When iron rusts, a chemical change occurs.
→ Yes, iron oxidizes.
✔ Chemical change
10. An ice cream melting is a chemical change.
→ It’s just changing from solid to liquid. No new substance.
✘ Incorrect — this is a physical change
---
#### Part A:
1. Physical
2. Chemical
3. Physical
4. Chemical
5. Chemical
6. Chemical
7. Physical
8. Physical
9. Physical
10. Physical
#### Part B:
1. False (it's physical)
2. True (chemical)
3. True (physical)
4. True (physical)
5. False (chemical)
6. False (chemical)
7. True (chemical)
8. True (physical)
9. True (chemical)
10. False (physical)
---
- Physical changes involve changes in state, shape, size, or dissolving without altering the substance's chemistry.
- Chemical changes involve reactions that produce new substances, often with signs like:
- Color change
- Gas production
- Formation of precipitate
- Light or heat released
- Odor change
Let me know if you'd like this formatted as a printable answer sheet!
- Part A: A list of 10 scenarios, asking whether each is a physical change or a chemical change.
- Part B: A list of 10 statements, asking you to identify the type of change (physical or chemical) based on the description.
Since I can't view images directly, I’ll solve the problem based on the text you’ve provided. Let me go through each part step by step and explain the reasoning behind each answer.
---
✔ Part A: Identify Physical or Chemical Change
We are to determine if each process is a physical change or a chemical change.
> Physical change: The substance changes form, but not its chemical identity (no new substances formed).
> Chemical change: A new substance is formed; the molecular composition changes.
Let’s analyze each one:
---
1. A chocolate bar is melted in the sun.
→ Melting is a phase change (solid → liquid), no new substance.
✔ Physical change
2. Two chemicals are mixed together and a gas is produced.
→ Gas production indicates a reaction (e.g., bubbles = CO₂). New substance formed.
✔ Chemical change
3. A piece of paper is torn into pieces.
→ Only size changed; no new substance.
✔ Physical change
4. A candle is lit.
→ Burning involves combustion (wax + oxygen → CO₂ + water).
✔ Chemical change
5. Two substances are mixed and light is produced.
→ Light emission often indicates a chemical reaction (e.g., glow sticks).
✔ Chemical change
6. A piece of iron rusts and turns brown.
→ Rusting is oxidation (iron + oxygen → iron oxide). New compound.
✔ Chemical change
7. Melting an ice cube.
→ Solid to liquid water — same molecule (H₂O).
✔ Physical change
8. Chlorophyll is dissolved in milk.
→ Dissolving is physical; no reaction (assuming it's just mixing).
✔ Physical change
9. A thermometer is broken over a sample.
→ Breaking glass is a physical change. No new substances.
✔ Physical change
10. A marshmallow is cut in half.
→ Size changed, not composition.
✔ Physical change
---
✔ Part B: Identify the Type of Change Based on Statements
Now we interpret each statement to determine if it describes a physical or chemical change.
1. Changing the physical state of a pure substance is a chemical change.
→ FALSE. Changing state (e.g., melting, boiling) is physical.
✘ Incorrect statement — this is not a chemical change.
2. The appearance of a new color means a chemical change has occurred.
→ Often true (e.g., rusting, burning). Color change can indicate a new substance.
✔ Chemical change
3. Evaporation is a physical change.
→ Liquid to gas — no new substance.
✔ Physical change
4. Dissolving a sugar cube in water is a physical change.
→ Sugar molecules remain intact; just dispersed. Can be reversed.
✔ Physical change
5. Combining hydrogen and oxygen to make water is a physical change.
→ This is a chemical reaction: 2H₂ + O₂ → 2H₂O. New substance.
✘ Incorrect — this is a chemical change
6. Burning wood is a physical change.
→ Wood burns → ash, CO₂, etc. New substances.
✘ Incorrect — this is a chemical change
7. Lighting a match is a chemical change.
→ Combustion occurs. Flame, heat, gases produced.
✔ Chemical change
8. Freezing steam results in ice.
→ Gas → solid. Still H₂O. Phase change.
✔ Physical change
9. When iron rusts, a chemical change occurs.
→ Yes, iron oxidizes.
✔ Chemical change
10. An ice cream melting is a chemical change.
→ It’s just changing from solid to liquid. No new substance.
✘ Incorrect — this is a physical change
---
✔ Final Answers
#### Part A:
1. Physical
2. Chemical
3. Physical
4. Chemical
5. Chemical
6. Chemical
7. Physical
8. Physical
9. Physical
10. Physical
#### Part B:
1. False (it's physical)
2. True (chemical)
3. True (physical)
4. True (physical)
5. False (chemical)
6. False (chemical)
7. True (chemical)
8. True (physical)
9. True (chemical)
10. False (physical)
---
🔍 Summary of Key Concepts:
- Physical changes involve changes in state, shape, size, or dissolving without altering the substance's chemistry.
- Chemical changes involve reactions that produce new substances, often with signs like:
- Color change
- Gas production
- Formation of precipitate
- Light or heat released
- Odor change
Let me know if you'd like this formatted as a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of worksheet on chemical vs physical properties and changes answer key.
