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Chapter 8 Outline
8.1 – Chemical
Equations
The symbols and formulas used to
represent reactants and products
Reading and Writing Chemical Equations:
1. Represent the Facts
2. Use correct formulas for compounds:
Ionic – SWAPPING
Molecular – PREFIXES
Diatomics – AUTOMATICALLY get a subscript “2”
Silly Phrase:
Reading and Writing Chemical Equations:
Metals are the symbol only:
Magnesium metal = Mg
Copper metal = Cu
**No numbers or charges!!**
Reading and Writing Chemical Equations:
3. Law of Conservation of Mass:
Nature balances the reactions, so we must too! We will use COEFFICIENTS which match what nature does.
Types of Equations
Word Equation
Shows reactants and products in WORDS
For now these will be given to you
Example:
Methane Gas + Oxygen Gas Carbon dioxide + Water
Types of Equations
Formula Equation
Uses Formulas
Example:
CH4 + O2 CO2 + H2O
Types of Equations
Balanced Equation
Number of each atom on the left matches the number on the right
THIS IS WHAT NATURE DOES!
Example:
CH4 + 2O2 CO2 + 2H2O
Other Symbols
s = solid
l = liquid
g = gas
aq = aqueous = dissolved in water
Reversible Reaction
Add Heat
Significance of an Equation
Will give us information about the amounts of reactants and products
That’s Chapter 9!
Reversible Reactions – Can proceed in either direction.
Balancing Reactions
Most can be done by inspection STEPS:1. Write the WORD EQUATION (for now given)
Ex. Water Hydrogen Gas + Oxygen Gas
2. Replace words with formulas
Water Hydrogen Gas + Oxygen Gas
H2O H2+
O2
3. Balancing
Balance one atom at a time
Start with elements that are on each side one time only
Balance polyatomics (like NO3) as an entire group when possible
Balance O and H last
Water Hydrogen Gas + Oxygen Gas
H2O O2 +H2
H
O
Count atoms to check!
Practice Problems
More Practice Problems
More Practice Problems
8.2 – Types of Reactions
1. Synthesis
Combining 2 or more reactants to form one product
A + X AX
Example:Magnesium + Oxygen Gas Magnesium oxide
8.2 – Types of Reactions
2. Decomposition
Breaking down 1 reactant into 2 or more products
AX A + X
Example:Silver oxide Silver metal + Oxygen gas
Hydrogen peroxide Water + Oxygen gas
8.2 – Types of Reactions
3. Single Displacement
One element replacing another in a compound
A + BX B + AX
A replaces the one it is most similar to!
Example:Iron + Copper (II) sulfate Copper + Iron (II) sulfate
Honors: You must be able to predict products!!
8.2 – Types of Reactions
4. Double Displacement
Two elements switch places in compounds
AX + BY AY + BX
Example:Sodium chloride + Silver(I) nitrate Sodium nitrate + Silver(I) chloride
4 Types of Reactions Review:
(Stop after Dbl Disp)
8.2 – Types of Reactions
4. Double Displacement
You must be able to predict products for this type of reaction!
Example:
Iron (II) sulfide + Hydrogen chloride
Activity Series
Activity = Ability to react Activity Series = List of elements by activity High on the list means the element can
replace those below it Helps us determine whether a reaction will
or will not happen
Activity Series
LiKCaNaMgAlZnFeCoNiSnPbCuHgAg
Most active on this list
Least active on this list
Activity SeriesLiKCaNaMgAlZnCrFeCoNiSnPbCuHgAg
For a single displacement reaction to occur, the SINGLE REACTANT must be HIGHER than the one in the compound
Example: 2Al + 3ZnCl2 -> 3Zn + 2AlCl3
Example: Co + 2NaCl -> CoCl2 + 2Na
Solubility
Solubility = Ability to dissolve
Soluble = DissolvesIn Water = Aqueous – aq
Insoluble = Does NOT DissolveSolid = s = precipitate
Solubility
Solubility Rules (these will be given to you on test): Group 1 and Ammonium compounds ARE soluble Acetate, Nitrate, and chlorate compounds ARE
soluble Group 17 (other than F) ARE soluble EXCEPT when
with Ag, Hg2+2, and Pb Sulfates ARE soluble EXCEPT when with Ba, Sr, Pb,
Ca, Ag, Hg2+2 Carbonates, Hydroxides, Oxides, Sulfides,
Phosphates, Oxalates are INSOLUBLE
**Start at the top and work down. STOP when you hit the first rule that applies to ANY
PART of you compound**
Solubility
Examples:
Cu(NO3)2 =
2NaI( ) + HgCl2( ) 2NaCl ( ) + HgI2 ( )
