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Chapter 4, section 1 Chemical Changes I will describe the signs of a chemical change in matter.
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Agree Disagree 1._______ ________ 2._______ ________ 3._______ ________ 5._______ ________ 4._______ ________ All chemical changes result in a new substance being formed. All chemical reactions produce heat. A chemical reaction caused the Statue of Liberty to become green. A change in smell is usually a sign of a physical change Some chemical reactions can create light.
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I. Chemical Change A. Occurs when bonds in compounds break and new compounds form 1. In a physical change, compounds remain the same
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Metal elements bonding with oxygen
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II. Evidence A. chemical reactions will always have: - formation of a new substance - a change in energy http://www.youtube.com/watch?v=66kuhJkQCVM
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B. Visual Evidence: 1. Precipitate – when two liquids react and form a solid substance 2. Color change 3. Gas produced 4. Change in odor (smell)
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http://www.youtube.com/watch?v=DITY2rXYU-I
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http://www.youtube.com/watch?v=JAeOP2MfrDY&list=TLJvZzUIA5KeR y6b7rNi2dHxKjeqYsLjFE Tons and Tons of Precipitation Reactions!
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C. Energy Evidence 1. Temperature decrease = endothermic 2. Temperature increase = exothermic http://www.youtube.com/watch?v=Jzoi7dJAiSc&feature=related
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http://www.youtube.com/watch?v=cZMkqagL8Ps Let’s Review Chemical Changes!
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Agree Disagree 1._______ ________ 2._______ ________ 3._______ ________ 5._______ ________ 4._______ ________ All chemical changes result in a new substance being formed. All chemical reactions produce heat. A chemical reaction caused the Statue of Liberty to become green. A change in smell is usually a sign of a physical change Some chemical reactions can create light.
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Please pull out your science book to pg 660 and start reading
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