Chapter 8 -...
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Chapter 8 Lesson 1 Chemical vs Physical change
Transcript of Chapter 8 -...
Chapter 8
Lesson 1
Chemical vs Physical change
Materials Needed Today
Please take these materials out of your backpack.
•Pencil
Hot Sync Monday 2/3/14
Answer the following questions in complete sentences on your hot sync.
chemical property
chemical change
dissolving
8.1 Chemical Properties and Changes
Ability to Change
• In a chemical change, the properties that give a substance its identity change.
8.1 Chemical Properties and Changes
• Properties of matter help identify objects.
• Properties are either physical or chemical.
What properties do elements have?
Ability to Change (cont.)
• A chemical property is the ability or inability of a substance to combine with or change into one or more new substances.
8.1 Chemical Properties and Changes
Chemical Properties
• Examples of chemical properties include burning or rusting.
• Some substances do not react.
8.1 Chemical Properties and Changes
Physical Properties
• Physical properties can be observed without changing the substance.
8.1 Chemical Properties and Changes
Chemical and Physical Changes
• Chemical changes change one substance into another substance.
• Usually chemical changes cannot be easily reversed.
• Changing Pennies
• http://chemistrytwig.com/2011/08/12/turn-pennies-into-gold/
8.1 Chemical Properties and Changes
Property Changes
PENNY LAB Lab in your notes:
• Question: What will happen if we drop a penny into a solution of zinc, sodium hydroxide, and water?
• Hypothesis:
Penny Lab
• Experiment:
• Materials U.S. copper pennies dated 1982 or earlier Zinc, granular NaOH (3 Molar or so) Distilled Water
• Procedure 1.) Mix NaOH 3M and about1 gram Zinc in water, heat on hot plate (or stove) until steaming, in a ceramic dish. 2) Add Penny and let sit 5-10 minutes 3.) Remove after chemical reaction occurs. 4.) Dry off pennies and place them on a towel. 5.) Place them in a beaker of distilled water. 6.) Using tongs, heat them in Bunsen burner until chemical reaction takes place.
Penny Lab
• Results:
• Zinc reacted with sodium hydroxide
– When the penny was put into the solution the zinc attached to the copper penny coating it.
– When the penny was heated the outer layer of zinc combined with the copper to create Brass.
• Conclusion:
Forming New Substances
• All chemical changes produce substances that are different from the starting substances.
– A compound is decomposed into its elements.
– Two elements join to form a compound.
8.1 Chemical Properties and Changes
Physical Changes
• A physical change is a change in which the properties of a substance change but the identity of the substance remains the same.
• Dissolving is a process in which substances mix evenly with one another.
8.1 Chemical Properties and Changes
Net Release of Energy (cont.)
• An exothermic process releases energy.
• The products in an exothermic reaction have less energy than the reactants.
8.3 Energy and Chemical Change
Net Release of Energy (cont.)
• An endothermic process absorbs energy.
• The products in an endothermic reaction have a higher energy than the reactants.
8.3 Energy and Chemical Change
Lesson 1 Review
Which is a chemical change?
A boiling
B burning
C dissolving
D melting
8.1 Chemical Properties and Changes
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
Lesson 1 Review
Which is NOT a chemical change?
A sodium metal and chlorine gas react to form salt
B salt dissolving in water
C paper burning
D iron rusting
8.1 Chemical Properties and Changes
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
Lesson 1 Review
Which is NOT a physical change?
A melting
B boiling
C dissolving
D burning
8.1 Chemical Properties and Changes
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
Materials Needed Today Please take these materials out of your backpack.
•Pencil
Hot Sync Tuesday 2/4/14
Answer the following questions in
complete sentences on your hot sync.
