1. Student Objective Warm Up
Identify the indicators that a chemical change/reaction has occurred.
Warm Up
WHAT DO YOU THINK????
How do you know if a chemical reaction has taken place??

2. Add to Physical vs Chemical Notes
A PHYSICAL change affects only the _____________________ of the material, but does not make a _______ _________________.
A CHEMICAL change forms _______ or more __________ substances.

3. Matter can undergo two kinds of changes…
Matter can undergo two kinds of changes…. PHYSICAL changes and CHEMICAL changes.

4. Differences between chemical and physical changes…
Add this to your worksheet & to your vocab. section!!
Add 2 examples to 3rd box on vocab. paper from next two slides
Chemical Change
a change that forms one or more new substances.
Physical Change a change that affects only the appearance of a material, but does not make a new substance.

5. Examples of Physical Changes….Why?
tearing paper
chopping wood
molding clay
melting ice

6. raw egg becomes cooked egg
                                      
raw egg becomes cooked egg
                                             
                      
cake mix becomes cake
                                       
                                       
paper becomes ash
steel becomes rust
EXAMPLES OF CHEMICAL CHANGES….Think about why each of these is a “chemical change”.

7. How do you know if a chemical reaction has taken place and a new substance is made?
Use the following slides to find out as you complete your “Indicators of a Chemical Change or Reaction” worksheet

8. Indicators of a Chemical Reaction Occurring:
Sometimes a gas is produced, which you might see as bubbles in a liquid.

9. Indicators of a Chemical Reaction Occurring:
Other times, a solid may appear when two solutions are mixed. A solid that forms from mixing two solutions during a chemical reaction is called a precipitate.

10. Indicators of a Chemical Reaction Occurring:
Still other times, a color change or a change in other properties may tell you that a new substance has formed.

11. Indicators of a Chemical Reaction Occurring:
Sometimes heat and/or light are produced when a new substance is formed.

12. IMPORTANT
All of these indicators are evidence of a chemical reaction. But they do not always mean that a chemical reaction has taken place. Sometimes, physical changes give similar results! Take for example boiling water. Don’t you observe bubbles indicating a gas has been made, but is it a new substance? In this case, the liquid water has turned into gas water……it’s still water! Just a change in state has occurred, not the creation of a new substance!
The key characteristic of a chemical reaction is the production of new substances that are chemically different from the starting substances!

13. Touching Cactus Gives Little Pricklies.
REVIEW: INDICATORS OF A CHEMICAL REACTION
(List these at the bottom of your worksheet)
Temperature change
Color Change:
Light produced
Chemical Interactions Page 19
Gas Produced
Precipitate
Touching Cactus Gives Little Pricklies.

14. Virtual Lab: Reversible & Irreversible changes.
Fill-in-the-Blanks
*Reading Comprehension - Properties and Changes
Virtual Lab: Reversible & Irreversible changes.
Click yellow “Fullscreen” button
Sound off, subtitles on
When you have completed the mission click yellow “Close” button & then scroll down to find QUIZ.
Website for Fill-in-the-blanks:
Website for Virtual Lab:
Website for Mission:

15. Try these sites to see if you and your partner really know about physical and chemical changes.

16. Where’s the Evidence of a Chemical Reaction?
Conclusions:
Where’s the Evidence of a Chemical Reaction?
Look at the reactions on the next chart. Fill in the last two columns by putting your answers on your worksheet.

17. Where’s the Evidence? Activity
Reaction
Observations Before Reaction
1. Sodium carbonate (powder) + hydrochloric acid
2. sugar + heat
3. Copper sulfate + sodium carbonate solutions
Was there a chemical reaction?
Indicators?
Observations
After Reaction
Describe the change that occurred

18. Where’s the Evidence? Activity
Reaction
Observations Before Reaction
1. Sodium carbonate (powder) + hydrochloric acid
2. sugar + heat
3. Copper sulfate + sodium carbonate solutions
Was there a chemical reaction?
Indicators?
Observations
After Reaction
Describe the change that occurred
YES
color change
gas produced
turned white
bubbles formed
turned brown
looks liquidy
YES
color change
thick stuff formed in the clear liquid
2 clear liquids turned blue
YES
color change
precipitate formed