Chemistry
Chapter 11 Note Packet
Mr. Fedell
(student’s edition)
Chapter 11 problems: RC 41, 43, 44, 50, 52
CT 67
good figures in the book to look at.... Word on the street is that looking at illustrations,
tables, and figures in the book is a good idea. As always your book has many great tables, figures
and example problems…you should be utilizing your book.
11.1 - Chemical Equations
Chemical equations represent, with symbols and formulas, the reactants and products in a
chemical reaction.
reactants

products
chemical equations describe chemical reactions
requirements for all chemical equations:
must show all reactants and products
formulas must be correct
Law of Conservation of Mass must be satisfied (equation must be balanced)
H2
+

yields
Cl2
say
2 HCl
other example – decomposition of sodium chloride – start from scratch – use symbols, heat, etc.
ex: NaCl (s) = solid sodium chloride
water)
H2O (l) - liquid water (not aqueous - redundant)
other symbols to know:
= heat
NaCl (aq) = solution of sodium chloride (in
= one way reactions
= catalyst*
= reversible reaction
= gas
= precipitate (solid - only found on products
side)
*a substance that speeds up a reaction without being used up in the reaction
Significance of a chemical equation: 2 Na
Atoms
Molecules
0
Molar mass
+
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Cl2

1
≠
2 NaCl
means…
2 (not equal, doesn’t have to)
Balancing Chemical Equations - truly a trial and error process if there ever was one
Helpful hints:
1. 1 atom at a time
2. Balance atoms that appear only 1X per side first
3. Balance polyatomic ions as whole units
4. Balance diatomic elements last
5. Save H + O for last
if this doesn’t succeed, try doubling everything (particularly with combustion)
Let’s try examples from worksheet 11-1…
11.2 - Types of Chemical Reactions
5 types - synthesis, decomposition, combustion, single replacement, double replacement
remember – “first you’ve got to find the right products, then you gotta balance!”
synthesis (
) - needs energy to happen
general formula
ex.
Ba
+
S

Mg
+
Cl2

Al
+
Cl2

Na
+
O2

decomposition (
or
) - needs energy to happen (usually
)
general formula
ex.
FeCl3 
HgO

MgSO4 · 7 H2O
(hydrate)

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combustion - the reaction of hydrocarbons and oxygen to yield...when you just say CHO...
general formula
ex.
combustion of CH4, C3H8, C4H10*, C2H5OH
single replacement - take place in
solution - need very little energy to happen
2 types:
a) General Formula ex
+
Mg

AlCl3 +
Ca

Ca
HOH 
HI
+
b) General Formula
ex
NaCl +
F2

BaS
O2

+
double replacement - again - aqueous solution - little energy - usually forms one soluble
ionic product (aka - aqueous) and either a ppt, water, or a gas that bubbles out of water
general formula
ex.
FeCl3 +
NaOH 
H2SO4 +
NaOH 
NH4Cl +
NaOH 
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Activity Series of the Elements
hey, some reactions happen and some don’t
for synthesis, combustion, and decomposition, we will assume they all happen given
sufficient activation energy (
)
for single replacement, use the
Ca
+
H2O
yields
Al
+
H2O
yields
Al
+
HI
yields
Cu
+
HI
yields
NaCl +
F2
yields
NaF
+
Cl2
yields
for the activity series, any single element above an element in a compound will replace it
top 5 elements react with
metals above H react with
the nonmetal reactivity series is
for double replacement reactions, use a
1.
2.
3.
if one of the products formed is water, the reaction happens
if a gas is formed, the reaction happens
if an insoluble product forms (I or Ss), the reaction happens (actually a reaction
may happen when two soluble products form, but it doesn’t go to completion and
is not directly observable)
Na2CrO4
+
FeCl3 +
KOH
HCl + NaOH
KCl



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NIB - Solubility Trends
Cations -
very soluble very insoluble-
Anions -
very soluble for monatomics
very insoluble
sulfides -
general trend -
Showing Energy Changes in Equations
endothermic - put in heat
- write on the ______________ side of the equation
or….
exothermic - releases heat
- write on the right side of the equation
Some helpful notes on writing phases in chemical reactions
1. Metals are solids (except
)
2. In single and double replacement reactions, reactants that are compounds are always aqueous.
3. In single and double replacement reactions, products that are compounds should have their
phases identified using a solubility chart (aqueous vs. precipitate)
4. In synthesis and decomposition reactions, ionic compounds are solids.
5. In combustion reactions, the water, CO2, and O2 are gases. The hydrocarbon is hard to tell, but
is usually a liquid after C=6 or higher.
6. Most other covalent compounds are gases.
7. Acids (chemicals starting with hydrogen) are always aqueous.
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