identify the following as physical (p) or chemical (c) changes.\n1. nacl (table salt) dissolves in…

Explanation:

Step1: Recall physical - chemical change criteria

Physical changes don't change substance identity; chemical changes form new substances.

Step2: Analyze each case

1. NaCl dissolving in water is a physical change as no new substance is formed. Just a mixture of ions in water. So it's P.
2. Silver tarnishing is a chemical change as silver reacts with sulfur - containing compounds in air to form silver sulfide. So it's C.
3. Cutting an apple is a physical change as it only changes the physical form, not the chemical composition. So it's P.
4. Heating water to steam is a physical change as it's a phase change of water from liquid to gas without changing the chemical identity of water. So it's P.
5. Baking soda reacting with vinegar is a chemical change as carbon dioxide, water and other products are formed. So it's C.
6. Iron rusting is a chemical change as iron reacts with oxygen and water to form iron oxide. So it's C.
7. Alcohol evaporating is a physical change as it's a phase change from liquid to gas without changing the chemical nature of alcohol. So it's P.
8. Ice melting is a physical change as it's a phase change from solid to liquid of water without changing the chemical identity of water. So it's P.
9. Milk souring is a chemical change as bacteria convert lactose in milk into lactic acid. So it's C.
10. Sugar dissolving in water is a physical change as no new substance is formed, just a sugar - water solution. So it's P.
11. Wood rotting is a chemical change as microorganisms break down the complex organic compounds in wood. So it's C.
12. Pancakes cooking is a chemical change as heat causes chemical reactions in the batter like the Maillard reaction. So it's C.
13. Grass growing is a chemical change as plants use photosynthesis and other biochemical processes to grow and form new substances. So it's C.
14. Inflating a tire is a physical change as it just changes the volume of air in the tire, no new substances are formed. So it's P.
15. Food digestion is a chemical change as enzymes break down complex food molecules into simpler ones. So it's C.
16. Paper towel absorbing water is a physical change as it's just a process of capillary action without changing the chemical nature of either the paper or water. So it's P.

Answer:

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