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Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Chapter 8Chapter 8Chemical Equations Chemical Equations
and Reactionsand ReactionsSections 1 and 2
Describing Chemical ReactionsTypes of Chemical Reactions
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Section 1Section 1
Describing Chemical Reactions
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Oh, That Curious Ira Remsen!Oh, That Curious Ira Remsen!
1846-1927
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Ira Remsen DemoCu (s) + HNO3 (aq) CuNO3 (aq) + H2 (g)
Chemical Reactionshttp://www.metacafe.com/watch/650550/nitric_acid_acts_upon_a_copper_penny_experiment/
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Indications of a Chemical Indications of a Chemical ReactionReactionProof: one or more substances has
changed identity – chemical change1. Evolution of energy as heat and/or
light2. Production of a gas3. Formation of a precipitate4. Color change
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Red, White and Blue Reaction http://www.chem.ox.ac.uk/vrchemistry/FilmStudio/redwhiteblue/page01.htm
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Ind
icati
on
s of
a R
eact
ion
In
dic
ati
on
s of
a R
eact
ion
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Characteristics of a Chemical Characteristics of a Chemical ReactionReaction1. The equation must contain the correct
formulas for the reactants and products.
• Diatomic elements: I2 Br2 Cl2 F2 O2 N2 H2
2. 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. 261-275
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Diatomic ElementsDiatomic Elements
p. 263
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Additional SymbolsAdditional Symbols
p. 226
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Additional SymbolsAdditional Symbols
p. 226
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Balancing Chemical EquationsBalancing Chemical Equations1. If the reaction is described by a
paragraph, write the word equation.
2. Write the formula for each reactant and product to get the formula equation.
3. Balance the equation.
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Balancing Chemical EquationsBalancing Chemical EquationsGOAL OF THE GAME:To get the same number of atom of
each element in the reactant and the product.
To obey the law of conservation of mass.
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Balancing Chemical EquationsBalancing Chemical EquationsRULES OF THE GAME:Only coefficients can be added or
changed.Once formulas are written subscripts
can not be changed.
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Balancing Chemical EquationsBalancing Chemical EquationsTIPS FOR PLAY:Balance the different types of atoms
one at a time.First balance elements that appear
only once on each side.Balance polyatomic ions that appear
on both sides as a single unit.Balance H and O last.
page 271
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Balancing Chemical EquationsBalancing Chemical EquationsTIPS FOR PLAY:Try keeping a tally for each element
on each side below the equation.If it could be balanced by a
coefficient of 1½ - use it- then multiply all coefficients in the equation by 2.
Practice
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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___H2 + ____N2 → ____NH3
____NaClO3 → ____NaCl + ____O2
___Al2(SO4)3 + ___Ca(OH)2 → ____Al(OH)3 + ____CaSO4
____C2H6 + ____O2 → ____CO2 + ____H2O
Chapter 8 Section 1 Describing Chemical Reactions p. 261-275
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Sample Problem p.272Sample Problem p.272The 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
