Question

part a can you recognize the chemical and physical changes that happen all around us? if you change the way a substance is made, a new substance, a physical change (p) has occurred. if the substance physical and chemical changes 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 vinegar. 6. fe (iron) rusts. 7. alcohol evaporates. 8. ice melts. 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 chemical change 1. a change in the physical and chemical properties 2. a new substance is formed physical property 1. observed with senses 2. determined without destroying matter 1. indicates how a substance reacts with something else 2. matter will be changed into a new substance after the reaction 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.

Explanation:

Step1: Recall physical and chemical change definitions

Physical change: no new substance formed, change in size, shape or state. Chemical change: new substance formed.

Step2: Analyze each item in Part A

1. NaCl (Table Salt) dissolves in water - Physical change (P), no new substance.
2. Ag (Silver) tarnishes - Chemical change (C), new substance (silver sulfide).
3. An apple is cut - Physical change (P), no new substance.
4. Heat changes H₂O to steam - Physical change (P), change of state.
5. Baking soda reacts to vinegar - Chemical change (C), new substances (carbon - dioxide etc.).
6. Fe (Iron) rusts - Chemical change (C), new substance (iron oxide).
7. Alcohol evaporates - Physical change (P), change of state.
8. Ice melts - Physical change (P), change of state.

Step3: Analyze each item in Part B

1. Blue color - Physical property (P), observed with senses.
2. Density - Physical property (P), measured without changing substance.
3. Flammability (burns) - Chemical property (C), indicates reaction.
4. Solubility (dissolves) - Physical property (P), no new substance.
5. Reacts with acid - Chemical property (C), indicates reaction.
6. Supports combustion - Chemical property (C), indicates reaction.
7. Sour taste - Physical property (P), observed with senses.
8. Melting point - Physical property (P), measured without changing substance.
9. Reacts with water - Chemical property (C), indicates reaction.
10. Hardness - Physical property (P), measured without changing substance.
11. Boiling point - Physical property (P), measured without changing substance.
12. Luster - Physical property (P), observed with senses.
13. Odor - Physical property (P), observed with senses.
14. Reacts with air - Chemical property (C), indicates reaction.
15. Food is digested - Chemical change (C), new substances formed.
16. Paper towel absorbs water - Physical change (P), no new substance.
17. A tire is inflated - Physical change (P), no new substance.
18. Grass grows - Chemical change (C), new substances formed in growth process.
19. Pancakes cook - Chemical change (C), new substances formed in cooking.
20. Wood rots - Chemical change (C), new substances formed in decay.
21. Sugar dissolves in water - Physical change (P), no new substance.
22. Milk sours - Chemical change (C), new substances formed.

Answer:

Part A:

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

Part B:

1. P
2. P
3. C
4. P
5. C
6. C
7. P
8. P
9. C
10. P
11. P
12. P
13. P
14. C
15. C
16. P
17. P
18. C
19. C
20. C
21. P
22. C