Remember that during a physical change, we change the way matter looks but we do not break bonds or make new ones.  Therefore, physical changes would not alter the chemical formula of the substance.  During a chemical change, bonds are broken and atoms rearrange.

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.

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.

Answers:

1. Physical

2. Chemical

3. Physical

4. Physical

5. Chemical

6. Chemical

7. Physical

8. Physical

9. Chemical

10. Physical

11. Chemical

12. Chemical

13. Chemical

14. Physical

15. Chemical

16. Physical