1. Chemical Reactions 7.1 Chemical reactions alter arrangements of atoms.
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NEW CHAPTER
Chemical Reactions
the BIG idea
Chemical reactions form new substances by breaking and making chemical bonds.
7.1
Chemical reactions alter arrangements of atoms.
7.2
The masses of reactants and products are equal.
7.3
Chemical reactions involve energy changes.
7.4
Life and industry depend on chemical reactions.
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2. 7.1 Chemical reactions alter arrangements of atoms.
• Chemical changes occur through chemical reactions.
• Evidence of a chemical reaction includes a color change, the formation of a precipitate, the formation of a gas, and a change in temperature.
chemical reaction
reactant
product
precipitate
catalyst
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OUTLINE

3. 7.1 Chemical reactions alter arrangements of atoms.
• Chemical changes occur through chemical reactions.
• Evidence of a chemical reaction includes a color change, the formation of a precipitate, the formation of a gas, and a change in temperature.
chemical reaction
reactant
• Chemical reactions change reactants into products.
product
precipitate
Reactants–bonds broken
oxygen
(O2)
(CH4)
methane +
Products–new bonds formed
carbon dioxide
(CO2)
(H2O)
water
catalyst
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OUTLINE

4. 7.1 Chemical reactions alter arrangements of atoms.
• Chemical changes occur through chemical reactions.
• Evidence of a chemical reaction includes a color change, the formation of a precipitate, the formation of a gas, and a change in temperature.
chemical reaction
reactant
• Chemical reactions change reactants into products.
product
precipitate
catalyst
VISUALIZATION
Observe how changing the concentration of a reactant can change the rate of a reaction.
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5. The masses of reactants and products are equal.
7.2
The masses of reactants and products are equal.
• Mass is conserved in chemical reactions.
• Chemical equations summarize chemical reactions.
law of conservation of mass
• Balanced chemical equations show the conservation of mass.
coefficient
CH4 O2 +
2O2 H O C
CO2
H2O +
2H2O H O C
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6. Chemical reactions involve energy changes.
7.3
Chemical reactions involve energy changes.
• Different bonds contain different amounts of energy.
• In an exothermic reaction, more energy is released than added.
bond energy
exothermic reaction
• In an endothermic reaction, more energy is added than released.
endothermic reaction
Exothermic Reactions
Bond Energy
Products (energy released)
Reactants (energy added)
Endothermic Reactions
Bond Energy
Products (energy released)
Reactants (energy added)
photosynthesis
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OUTLINE

7. Chemical reactions involve energy changes.
7.3
Chemical reactions involve energy changes.
• Different bonds contain different amounts of energy.
• In an exothermic reaction, more energy is released than added.
bond energy
exothermic reaction
• In an endothermic reaction, more energy is added than released.
endothermic reaction
VISUALIZATION
View examples of endothermic and exothermic reactions.
photosynthesis
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SECTION
OUTLINE

8. Life and industry depend on chemical reactions.
7.4
Life and industry depend on chemical reactions.
• Living things rely on chemical reactions that release energy from molecules.
respiration
Photosynthesis
C6H12O6 + 6O2
6CO2 + 6H2O + energy
Respiration
C6H12O6 + 6O2
6CO2 + 6H2O + energy
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OUTLINE

9. Life and industry depend on chemical reactions.
7.4
Life and industry depend on chemical reactions.
• Living things rely on chemical reactions that release energy from molecules.
respiration
• Different parts of modern society rely on chemical reactions.
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10. 7.1 Chemical reactions alter arrangements of atoms.
I. Chemical reactions alter arrangements of atoms.
chemical reaction
A. Atoms interact in chemical reactions.
1. Physical Changes
reactant
2. Chemical Changes
product
3. Reactants and Products
precipitate
4. Evidence of Chemical Reactions
catalyst
B. Chemical reactions can be classified.
C. The rates of chemical reactions can vary.
1. Concentration
2. Surface Area
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3. Temperature
4. Catalysts
KEY CONCEPT
SUMMARY

11. The masses of reactants and products are equal.
7.2
The masses of reactants and products are equal.
II. The masses of reactants and products are equal.
law of conservation of mass
A. Careful observations led to the discovery of the conservation of mass.
coefficient
B. Chemical reactions can be described by chemical equations.
C. Chemical equations must be balanced.
1. Balancing Chemical Equations
2. Using Coefficients to Balance Equations
3. Using the Conservation of Mass
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KEY CONCEPT
SUMMARY

12. Chemical reactions involve energy changes.
7.3
Chemical reactions involve energy changes.
III. Chemical reactions involve energy changes.
bond energy
A. Chemical reactions release or absorb energy.
exothermic reaction
B. Exothermic reactions release energy.
endothermic reaction
C. Endothermic reactions absorb energy.
D. Exothermic and endothermic reactions work together to supply energy.
photosynthesis
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KEY CONCEPT
SUMMARY

13. Life and industry depend on chemical reactions.
7.4
Life and industry depend on chemical reactions.
IV. Life and industry depend on chemical reactions.
respiration
A. Living things require chemical reactions.
B. Chemical reactions are used in technology.
C. Industry uses chemical reactions to make useful products.
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KEY CONCEPT
SUMMARY

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