Question

physical and chemical properties and changes
name
physical property

1. observed with senses
2. determined without destroying matter

chemical property

1. indicates how a substance reacts with something else
2. matter will be changed into a new substance after the reaction

identify the following as a chemical (c) or physical property (p):

1. blue color
2. density
3. flammability (burns)
4. solubility (dissolves)
5. reacts with acid
6. supports combustion
7. sour taste
8. melting point
9. reacts with water
10. hardness
11. boiling point
12. luster
13. odor
14. reacts with air

physical change

1. a change in size, shape, or state
2. no new substance is formed

chemical change

1. a change in the physical and chemical properties
2. a new substance is formed

identify the following as physical (p) or chemical (c) changes.

1. nacl (table salt) dissolves in water.
2. ag (silver) tarnishes.
3. an apple is cut.
4. heat changes h₂o to steam.
5. baking soda reacts to vinger.
6. fe (iron) rusts.
7. alcohol evaporates.
8. ice melts.
9. milk sours.
10. sugar dissolves in water.
11. wood rots.
12. pancakes cook.
13. grass grows.
14. a tire is inflated.
15. food is digested.
16. paper towel absorbs water.

physical and chemical changes
part a
can you recognize the chemical and physical changes that happen all around us? if you change the way something looks, but havent made a new substance, a physical change (p) has occurred. if the substance has been changes into another substance, a chemical change (c) has occurred.

1. an ice cube is placed in the sun. later there is a puddle of water. later still the puddle is gone.
2. two chemical are mixed together and a gas is produce.
3. a bicycle changes color as it rusts.
4. a solid is crushed to a powder.
5. two substances are mixed and light is produced.
6. a piece of ice melts and reacts with sodium.
7. mixing salt and pepper.
8. chocolate syrup is dissolved in milk.
9. a marshmallow is toasted over a campfire.
10. a marshmallow is cut in half.

Answer:

Part A (Identifying Physical (P) or Chemical (C) Changes)

1. An ice cube is placed in the sun...

• Explanation: Ice melts to water (state change) and water evaporates (state change). No new substance is formed.
• Classification: Physical Change (P)

2. Two chemicals are mixed... and a gas is produced.

• Explanation: A gas (new substance) is formed from the reaction of two chemicals.
• Classification: Chemical Change (C)

3. A bicycle changes color as it rusts.

• Explanation: Rust (a new substance, iron oxide) forms on the bicycle.
• Classification: Chemical Change (C)

4. A solid is crushed to a powder.

• Explanation: Only the size/shape changes (powder vs. solid). No new substance is formed.
• Classification: Physical Change (P)

5. Two substances are mixed and light is produced.

• Explanation: Light production often indicates a chemical reaction (e.g., combustion or energy-releasing reactions). A new substance is likely formed.
• Classification: Chemical Change (C)

6. A piece of ice melts and reacts with sodium.

• Explanation: Ice melts (physical change), but then water reacts with sodium (forming sodium hydroxide and hydrogen gas—new substances). The reaction is chemical.
• Classification: Chemical Change (C) (the reaction with sodium is the key chemical change)

7. Mixing salt and pepper.

• Explanation: Salt and pepper are just combined (no reaction, no new substance). This is a mixture.
• Classification: Physical Change (P)

8. Chocolate syrup is dissolved in milk.

• Explanation: Dissolving is a physical process (no new substance; syrup and milk retain their chemical identities).
• Classification: Physical Change (P)

9. A marshmallow is toasted over a campfire.

• Explanation: Toasting causes charring (carbonization) and chemical reactions (new substances like CO₂, ash, and caramelized sugars form).
• Classification: Chemical Change (C)

10. A marshmallow is cut in half.

• Explanation: Only the size/shape changes (halved). No new substance is formed.
• Classification: Physical Change (P)

Final Answers (Part A)

1. P
2. C
3. C
4. P
5. C
6. C
7. P
8. P
9. C
10. P

Additional Sections (Properties and Changes)

Physical/Chemical Properties (Top Section)

• Blue color: P (observed with senses, no destruction of matter).
• Density: P (measured without destroying matter).
• Flammability: C (describes how a substance reacts/burns, forming new substances).
• Solubility: P (dissolving is a physical process, no new substance).
• Reacts with acid: C (reaction forms new substances).
• Supports combustion: C (describes reaction with oxygen, forming new substances).
• Sour taste: P (observed with senses, no destruction of matter).
• Melting point: P (measured without destroying matter).
• Reacts with water: C (reaction forms new substances).
• Hardness: P (measured without destroying matter).
• Boiling point: P (measured without destroying matter).
• Luster: P (observed with senses, no destruction of matter).
• Odor: P (observed with senses, no destruction of matter).
• Reacts with air: C (reaction forms new substances, e.g., oxidation).

Physical/Chemical Changes (Middle Section)

1. NaCl dissolves in water: P (dissolving, no new substance).
2. Ag tarnishes: C (tarnish = silver sulfide, new substance).
3. An apple is cut: P (size/shape change, no new substance).
4. Heat changes H₂O to steam: P (state change, no new substance).
5. Baking soda + vinegar: C (gas (CO₂) and new substances form).
6. Fe rusts: C (rust = iron oxide, new substance).
7. Alcohol evaporates: P (state change, no new substance).
8. Ice melts: P (state change, no new substance).
9. Milk sours: C (lactic acid forms, new substance).
10. Sugar dissolves in water: P (dissolving, no new substance).
11. Wood rots: C (decomposition, new substances form).
12. Pancakes cook: C (chemical reactions, new substances form).
13. Grass grows: C (photosynthesis and growth involve new substances).
14. A tire is inflated: P (air added, no new substance).
15. Food is digested: C (breakdown into new substances, e.g., nutrients).
16. Paper towel absorbs water: P (absorption, no new substance).

Final Answers (Middle Section)

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