Download Types of Reactions

Types of Reactions
precipitate: a solid product that forms in an
aqueous solution reaction
Na2CO3 (aq) + Ca(NO3)2 (aq)
CaCO3(s) +
ppt
clear
Na2CO3
solution
clear
Ca(NO3)2
solution
2 NaNO3
(aq)
“chunks”
“sinkies”
“floaties”
cloudy solution
containing CaCO3(s)
and NaNO3(aq)
Key Terms
Term
Definition
soluble
able to be dissolved
insoluble
does not dissolve in solution
(or water)
an insoluble solid formed
precipitate
when two solutions are mixed
In an
Equation
(aq)
(ins)
(s)
Using Solubility Rules
– Most solubility rules are written based on the
negative ion or anion
•
Soluble compounds contain…
Insoluble compounds contain…
For these compounds, common exceptions are
INSOLUBLE.
For these compounds, common exceptions are
SOLUBLE.
How to Determine if a Compound is
Soluble or Insoluble?
• Find the anion in the compound.
• Find the rule in the solubility tables that
matches the ion.
• Double check to make sure the cation isn’t
listed as an exception.
Predict if the following compounds are
soluble or insoluble.
– CaCl2
Soluble
– CuSO4
Soluble
– Al2(CrO4)3
Insoluble
– Mg(OH)2
Insoluble
Insoluble
– AgCl
– SrS
Soluble
Predicting if a Precipitate will Form
–Precipitate reactions are precipitation
reactions.
–In order for a reaction to be a
precipitation reaction, there must be
• one solid product, which is the precipitate,
and
• both reactants should be aqueous solutions
Determine which reactions are precipitation
reactions or
reactions that will form a precipitate.
• Pb(NO3)2
+ KI
(aq)
(aq)
 PbI2
(s)
+ KNO3
(aq)
• (NH4)2CO3 + K2S  K2CO3
+ (NH4)2S
(aq)
(aq)
(aq)
(aq)
• Ag
+ Cu(NO3)2

(s)
(aq)
• Ba(OH)2
(aq)
AgNO3
+ Fe(ClO4)3
(aq)
NO
+ Cu
(aq)
NO
(s)
 Ba(ClO4)2 + Fe(OH)3
(aq)
YES
YES
(s)
Neutralization Reaction
• A reaction between and acid and a base which
results in the production of a salt and water.
ACID + BASE = SALT + WATER
HCl(aq) + NaOH(aq) = H2O(l) + NaCl(aq)
Mg(OH)2(s) + 2HCl(aq) = MgCl2(aq) + 2H2O(l)
9
Reduction-Oxidation Reaction
REDOX
• A reaction in which electrons are transferred from one
species to another.
• Oxidation means the loss of electrons.
• Reduction means the gain of electrons.
LEO says GER
Loss Electrons = Oxidation
Gain Electrons = Reduction
Many oxidation-reduction reactions are
single replacement reactions
Oxidation Reduction Reactions
(Redox)
0
1
0
1
2 Na  Cl 2  2 Na Cl
Each sodium atom loses one electron:
1
0
Na  Na  e
Each chlorine atom gains one electron:
0

1
Cl  e  Cl

LEO says GER :
Lose Electrons = Oxidation
1
0
Na  Na  e

Sodium is oxidized
Gain Electrons = Reduction
0

1
Cl  e  Cl
Chlorine is reduced
Rules for Assigning Oxidation Numbers
Rules 1 & 2
1. The oxidation number of any uncombined element
is zero
2. The oxidation number of a monatomic ion
equals its charge
0
0
1
1
2 Na  Cl 2  2 Na Cl
Rules for Assigning Oxidation Numbers
Rules 3 & 4
3. The oxidation number of oxygen in
compounds is -2
4. The oxidation number of hydrogen in
compounds is +1
1
2
H2O
Rules for Assigning Oxidation Number Rule 5
5. The sum of the oxidation numbers in the
formula of a compound is 0
1
2
H2O
2(+1) + (-2) = 0
H O
2
2 1
Ca(O H ) 2
(+2) + 2(-2) + 2(+1) = 0
Ca
O
H
Rules for Assigning Oxidation Numbers
Rule 6
6. The
sum of the oxidation numbers in the
formula of a polyatomic ion is equal to
its charge
? 2
N O3
X + 3(-2) = -1
N O
 X = +5

? 2
S O4
X + 4(-2) = -2
S O
 X = +6
2
Assigning Oxidation States
Example: Assign oxidation states to all atoms in the
following.
a. CO2  O = -2 (for each oxygen); C = +4
b. SF6  F = -1 (for each fluorine); S = +6
c. NO3-  O = -2 (each oxygen); N = +5
d. MnO4-  O = -2 (each oxygen); Mn = +7
e. HSO3-  O = -2 (each oxygen); H = +1, S = +4
f. H2O  H = +1 (each); O = -2
g. Li3N  Li = +1 (each); N = -3