Question

decide if the following are physical (p) or chemical (c) changes:
______ wood burning in a fire
______ sugar dissolving in kool - aid
______ iron rusting to produce iron (iii) oxide
______ water vapor condensing to form rain clouds
______ breaking a piece of glass
______ acid rain damaging a statue
______ wind and water weathering the side of a mountain
______ the combustion of gasoline inside of an automobile’s engine
______ water cooling to form an insulating layer of ice
______ the compression of air inside of a metal tank
______ food cools down on a dinner table
______ light causes the corrosion of hydrogen peroxide
______ fungus decompose plant material
______ ted so that it can be poured into a mold

Explanation:

To solve this, we determine if a change is physical (P, no new substance) or chemical (C, new substance forms):

1. Wood burning in a fire: Burning produces ash/gases (new substances) → C
2. Sugar dissolving in Kool - Aid: Sugar mixes, no new substance → P
3. Iron rusting to produce iron (III) oxide: Rust (new substance) forms → C
4. Water vapor condensing to form rain clouds: Water changes state (gas→liquid), no new substance → P
5. Breaking a piece of glass: Glass breaks, no new substance → P
6. Acid rain damaging a statue: Acid reacts with statue material (new substances) → C
7. Wind and water weathering the side of a mountain: Physical breakdown (no new substance) → P
8. The combustion of gasoline inside of an automobile’s engine: Gasoline burns, new substances (CO₂, H₂O, etc.) form → C
9. Water cooling to form an insulating layer of ice: Water changes state (liquid→solid), no new substance → P
10. The compression of air inside of a metal tank: Air is compressed, no new substance → P
11. Food cools down on a dinner table: Temperature change, no new substance → P
12. Light causes the corrosion of hydrogen peroxide: H₂O₂ decomposes (new substances) → C
13. Fungus decompose plant material: Decomposition forms new substances → C
14. (Assuming the last is “Metal is melted so that it can be poured into a mold”): Metal changes state (solid→liquid), no new substance → P

Answer:

s:

1. C
2. P
3. C
4. P
5. P
6. C
7. P
8. C
9. P
10. P
11. P
12. C
13. C
14. P (if the last is about melting metal)