Matter Changes Answer Key

Name:

Date:

🔬 Part 1: Physical and Chemical Changes

1. Circle the correct answer: Melting ice is a _______ change.

●

Physical

Chemical

2. Circle the correct answer: Burning wood is a _______ change.

Physical

●

Chemical

3. Check all that are physical changes:

✓

Cutting paper

Baking a cake

✓

Freezing water

Digesting food

4. Fill in the blank: In a physical change, the _________ of matter stays the same, but the _________ may change.

Answer: substance (or identity), shape (or form/state)

5. Fill in the blank: In a chemical change, a new _________ is formed with different _________.

Answer: substance, properties

📊 Part 2: Experiment Observations

6. You observe bubbles forming when vinegar is mixed with baking soda. This is evidence of a:

Physical change

●

Chemical change

7. Explain why rusting is a chemical change:

Answer: Rusting is a chemical change because iron combines with oxygen to form a new substance (iron oxide) with different properties than the original iron. The rust cannot be easily changed back to iron.

8. List three signs that indicate a chemical change has occurred:

Answer: 1. Color change, 2. Gas bubbles/odor, 3. Temperature change, 4. Formation of a precipitate (solid), 5. Light is produced (any three of these)

📖 Part 3: Reading Comprehension

9. True or False: All changes in matter can be easily reversed.

Answer: False - Physical changes can usually be reversed, but chemical changes cannot be easily reversed.

10. Compare and contrast physical and chemical changes:

Answer: Both types involve changes in matter. Physical changes only change appearance/state but keep the same substance (like melting ice). Chemical changes create new substances with different properties (like burning paper into ash). Physical changes are usually reversible; chemical changes are usually not reversible.