Worksheet 2.1, 2.4 – Physical & Chemical Changes

Put “P” if a physical change occurred and “C” if a chemical change occurred. In each case, explain your reasoning.

1. A clear liquid was left overnight. The next morning only a white solid was left in the container. _____

How do you know?

2. A clear yellow liquid and a colorless liquid were combined and a reddish-brown precipitate was formed. _____

How do you know?

3. A strip of metal was heated and a flash of light occurred _____

How do you know?

4. A blue solid was crushed into a powder. _____

How do you know?

5. A yellow powder and a gray powder were stirred together to form a grayish-yellow powder. _____

How do you know?

6. Two white powders were mixed together and became very cold, giving off an ammonia smell. _____

How do you know?

7. Phenolphthalein was present in a clear base solution making it pink. Another clear solution was added and the new solution turned clear. _____

How do you know?

8. Gray steel wool turned bluish-gray when heated and gained mass. _____

How do you know?

9. A white powder is dissolved in water. _____

How do you know?

10. A white powder was heated and a black substance and a clear liquid formed. _____

How do you know?

11. Flour, eggs, sugar and milk were stirred together to form a cake batter. _____

How do you know?

12. A cake batter was baked to form a cake. _____

How do you know?

13. A strip of metal was bent. _____

How do you know?

14. A nail rusted. _____

How do you know?

Determine which of the following are true or false, and for each false statement, substitute the word(s) which make the statement correct for the underlined word(s).

15. A change in state is a chemical change. _____

16. A change in composition is a chemical change. _____

17. A change in shape is a physical change. _____

18. Both physical and chemical changes involve energy changes. _____

19. The burning of wood is a physical change. _____

20. When ice cubes melt, a chemical change is occurring. _____

21. When mercuric oxide breaks down into its elements, mercury and oxygen, it has undergone a physical change. _____

22. The separation of a mixture is a physical change. _____

23. The melting of iron is a chemical change. _____

24. Milk turning sour is a physical change. _____

25. Salt water can be separated by distillation which is a physical change. _____