1. Review Physical & Chemical Changes
OBJECTIVE:
Review Physical &
Chemical Changes
WARM-UP:
Give the basic definition/idea for a physical change & a chemical change.

3. Physical Change
Physical changes – Just a change in appearance, no new substance made.
Physical property changes could include a change in: texture, shape, size, color, odor, volume, mass, weight, and density.

4. Chemical Change
Chemical changes- A new substance is made & one or more indicators is present.
5 Indicators: Temperature change, Color change, Gas produced, Light Produced, Precipitate

5. What is this?

6. Look at the ingredients!

7. Mix some iron powder, salt, and a few eyedroppers of water and watch the temperature rise to about 35 degrees Celsius.
You need to keep stirring but kids can feel the warmth if you pass it around. This is a chemical change releasing heat energy as the iron rusts. The air (oxygen) and iron combine to form Iron Oxide or rust and the catalysts to speed it up are salt and water.

8. Was this reaction exothermic OR endothermic?
84ºC = 183ºF
Was this reaction exothermic OR endothermic?
WHY?

9. WHAT IS THIS?
At outdoor school you will notice the orange mud in the wetlands.
This is caused by iron in the soil that rusts when exposed to oxygen in the water and the air.

10. During what season of the year would a car rust the most?(
Hint (
What made the iron rust faster?

11. 5. Evaluation Activity:
Look at the following slides and work with your partner to answer the questions on notebook paper
(Found in Chem Interactions 2005 p 52)

12. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
A student places two substances in a flask and measures the temperature once per minute while the substances react. The student plots the time and temperature data and creates the graph at left.

13. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
Reading Graphs:
What was the temperature in the flask at 4 minutes?
When was the first time the temperature was at 6ºC?

14. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
Calculating:
How many degrees did the temperature drop between 2 minutes and 5 minutes?

15. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
Interpreting Data:
Is the reaction endothermic or exothermic? Explain.

16. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
Inferring:
At what temperature did the reaction stop? How can you tell?

17. Energy in Chemical Changes
- Observing Chemical Change
Energy in Chemical Changes
Drawing Conclusions:
Suppose the temperature in the flask increased instead of decreased as the reaction occurred. In terms of energy, what kind of reaction would it be? Explain.

19. Is it a chemical or physical change?
Sugar dissolving in tea
Chemical Change
Physical Change

20. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

21. Correct!

22. Is it a chemical or physical change?
Logs burning
Chemical Change
Physical Change

23. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

24. Correct!

25. Is it a chemical or physical change?
Cutting paper
Chemical Change
Physical Change

26. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

27. Correct!

28. Is it a chemical or physical change?
Crushing an aspirin
Chemical Change
Physical Change

29. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

30. Correct!

31. Is it a chemical or physical change?
Metal rusting
Chemical Change
Physical Change

32. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

33. Correct!

34. Is it a chemical or physical change?
Lighter fluid burining
Chemical Change
Physical Change

35. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

36. Correct!

37. Is it a chemical or physical change?
An egg rotting
Chemical Change
Physical Change

38. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

39. Correct!

40. Is it a chemical or physical change?
An egg breaking
Chemical Change
Physical Change

41. OOPS! Did it change size, color, shape (Physical Change)? or
Did it become different matter (Chemical Change)?

42. Correct!

43. Review Worksheets
Work BY YOURSELF to complete the “Overview Chemical Reactions” WS, BOTH sides
Work BY YOURSELF to complete the “How Much Can You Remember…” WS, BOTH sides.
Go on to next slide when BOTH worksheets are done, BOTH SIDES of each.

44. Writing Activity
Write a paragraph about the difference between a chemical and physical change. Give examples of each.

45. Web Activities... Physical Changes /Chemical Changes Click here!
After webpage loads, click 2 times on star on left side of page.

46. Try these sites to see if you and your partner really know about physical and chemical changes.1. 2. 3.

47. Look at some chemical reactions… Click here
Click “OK” to run ActiveX Controls when needed.