You’ve uploaded a worksheet titled
“Introduction to Physical and Chemical Changes” that includes definitions, examples, and a “True or False” section for students to complete.
Let’s solve the True or False questions one by one, using the definitions provided in the worksheet:
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🔍 Definitions from the Worksheet:
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Physical change: A change in which matter does not change its identity (e.g., melting, freezing, boiling — still water).
→ *Matter can change state or shape but keeps its chemical identity.*
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Chemical change: A change in which one or more substances combine or break apart to form new substances.
→ *Always results in new substances with different properties.*
→ *Examples: burning, cooking, rusting, souring, etc.*
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✔ True or False Answers + Explanations:
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1. True
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Statement: If the answer is true, write “true” on the line. If the answer is false, replace the underlined word or phrase with what will make the sentence correct. Write the new word(s) on the line.
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Sentence: A substance that undergoes a
physical change, like melting, is still the same substance.
✔ Answer: True
Explanation: Melting is a physical change — ice turns to liquid water, but it’s still H₂O. The chemical identity doesn’t change.
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2. True
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Sentence: During a chemical change, atoms are
not gained or lost to make the new substance(s).
✔ Answer: True
Explanation: In chemical changes, atoms are rearranged to form new substances, but they are neither created nor destroyed (Law of Conservation of Mass). So no atoms are gained or lost — just reorganized.
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3. False
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Sentence: Dissolving, bending, crushing, breaking, and chopping are all examples of
chemical changes.
✘ Correction: Replace “chemical” with
physical
✔ Answer: physical
Explanation: These are all physical changes — you’re changing the form or size, but not the chemical identity. For example, crushing a can or dissolving sugar in water doesn’t create new substances.
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4. False
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Sentence: A change of state, such as boiling, is an example of a
chemical change.
✘ Correction: Replace “chemical” with
physical
✔ Answer: physical
Explanation: Boiling is a phase change — liquid water becomes water vapor, but it’s still H₂O. No new substances are formed → physical change.
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5. False
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Sentence: When hydrogen peroxide is poured on skin, it breaks down into water and oxygen gas. This is an example of a
physical change.
✘ Correction: Replace “physical” with
chemical
✔ Answer: chemical
Explanation: Hydrogen peroxide (H₂O₂) decomposes into water (H₂O) and oxygen gas (O₂) — two different substances. New substances are formed → chemical change.
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## 📝 Final Answer Key:
1.
True
2.
True
3.
physical
4.
physical
5.
chemical
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Parent Tip: Review the logic above to help your child master the concept of worksheet physical and chemical changes.
