1. Chemical Equations and Reactions
Mrs. Taylor
Chapter 8 Section 1 Describing Chemical Reactions p

2. Oh, That Curious Ira Remsen!
Chapter 8 Section 1 Describing Chemical Reactions p

3. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Demonstration
Demonstration
Ira Remsen Demo Cu (s) + HNO3 (aq)  CuNO3 (aq) + H2 (g)
Chemical Reactions nitric_acid_acts_upon_a_copper_penny_experiment/
Chapter 8 Section 1 Describing Chemical Reactions p

4. Indications of a Chemical Reaction
Proof: one or more substances has changed identity – chemical change
Evolution of energy as heat and/or light
Production of a gas
Formation of a precipitate
Color change
Chapter 8 Section 1 Describing Chemical Reactions p

5. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Demonstration
Demonstration
Red, White and Blue Reaction
Chapter 8 Section 1 Describing Chemical Reactions p

6. Indications of a Reaction
Chapter 8 Section 1 Describing Chemical Reactions p

7. Characteristics of a Chemical Reaction
The equation must contain the correct formulas for the reactants and products.
Diatomic elements: I2 Br2 Cl2 F2 O2 N2 H2
The law of conservation of mass must be satisfied. (Mass cannot be created or destroyed)
Coefficients – a whole number that appears in front of a formula in a chemical equation.
Chapter 8 Section 1 Describing Chemical Reactions p

8. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Diatomic Elements
Chapter 8 Section 1 Describing Chemical Reactions p
p. 263

9. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Additional Symbols
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p. 226

10. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Additional Symbols
Chapter 8 Section 1 Describing Chemical Reactions p
p. 226

11. Balancing Chemical Equations
RULES OF THE GAME:
Only coefficients can be added or changed.
Once formulas are written subscripts can not be changed.
Balance polyatomic ions that appear on both sides as a single unit.
Balance H and O last.
Chapter 8 Section 1 Describing Chemical Reactions p

12. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Practice
___H2 + ____N2 → ____NH3
____NaClO3 → ____NaCl + ____O2
___Al2(SO4)3 + ___Ca(OH)2 → ____Al(OH)3 + ____CaSO4
____C2H6 + ____O2 → ____CO2 + ____H2O
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13. Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
Sample Problem p.272
The reaction of zinc with aqueous hydrochloric acid produces a solution of zinc chloride and hydrogen gas. Write a balanced equation for the reaction
Insert Holt Chemistry Visualizing Matter Disc 1
Chapter 8 Section 1 Describing Chemical Reactions p

14. BALANCE THE EQUATIONS ____Al + ____N2 → ____AlN
____Fe ____O2 → ____Fe3O4
____ZnS ____O2 → ____ZnO ____SO2
____Na ____H2O → ____H ____NaOH
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