Transcript N e t I o n i c E q u a t i o n s

Net Ionic Equations
Equations attempt to show only
the exact particles involved in the
reaction.
Net Ionic Equations
You must first decide - are
substances written as molecules
or ions?
(NH4)2S + Fe(NO3)2
2NH4NO3 + FeS
This is a molecular equation.
(NH4)2S + Fe(NO3)2
S-2 + Fe+2
2NH4NO3 + FeS
FeS
This is the same equation
written in net ionic form.
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
Which are molecules?
Which are ions?
Seven rules to help you decide ions
or molecules.
Rule #1 - Binary acids
Strong Acids are written in ionic form.
Examples: HCl, HBr, HI
Weak Acids are written in molecular form.
Examples: All Others
Rule #2 - Ternary acids
Strong Ternary Acids:
the number of oxygen atoms
exceeds the number of hydrogen
atoms by two or more, are written
in ionic form.
Examples: H2SO4, HNO3
Rule #2 - Ternary acids
Weak ternary acids are written
in molecular form.
Examples: H3PO4
Rule #3 - Polyprotic acids
Those acids have more than one
ionizable hydrogen atom.
The first hydrogen is ionized.
The second and all other ionizations are
always weak.
Rule #4 - Bases
Hydroxides of Groups (IA) and (IIA),
except Be, are strong bases and
written in ionic form.
All others are weak bases and written
in molecular form.
Rule #5 - Salts
Salts are written in molecular
form if they are insoluble.
Salts are written in ionic form if
they are soluble.
Salt Solubility Rules
Salts of Group (IA) and ammonia are
soluble.
Acetates and nitrates are soluble.
Binary compounds of Group (VIIA),
except F, with metals, except Ag, Hg+1,
and Pb, are soluble.
Salt Solubility Rules
All sulfates are soluble, except those of
Ba, Sr, Pb, Ca, Ag, and Hg+1.
Except for those in Rule 1, carbonates,
hydroxides, oxides, sulfides, and
phosphates are insoluble.
Rule #6 - oxides
Oxides are always written in
molecular form.
Rule #7 - gases
Gases are always written in
molecular form.
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
molecule
or ion?
Which Rule?
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
molecule
or ion?
Which Rule?
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l)
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l)
molecule
or ion?
Which Rule?
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l) + SO3(aq)
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l) + SO3(aq)
To check the answer,
ask these two questions:
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l) + SO3(aq)
Do both sides of the arrow
have the same number of elements?
Write this in net ionic form:
H2SO4(aq)
H2O(l) + SO3(aq)
H+(aq) + HSO4-(aq)
H2O(l) + SO3(aq)
Do both sides of the arrow
have the same total charge?
Spectator ions
Ions appearing on
BOTH sides of
the equation.
Spectator ions
They are assumed
to take no part in
the reaction and
are canceled.
Spectator ions
They are NOT part
of a net ionic
equation.
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
molecule
or ion?
Ag2SO4(cr) + 2HNO3(aq)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + 2NO3-(aq)
Ag2SO4(cr) + 2HNO3(aq)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + 2NO3-(aq)
Ag2SO4(cr) + 2HNO3(aq)
molecule
or ion?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
molecule
or ion?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Ag2SO4(cr)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
molecule
Ag2SO4(cr)or ion?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2H+(aq) + 2NO3-(aq)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2H+(aq) + 2NO3-(aq)
Spectator ions?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2H+(aq) + 2NO3-(aq)
Spectator ions?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
Ag2SO4(cr) + 2HNO3(aq)
2Ag+(aq) + 2NO3-(aq) + H+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2H+(aq) + 2NO3-(aq)
Spectator ions?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2HNO3(aq)
Ag2SO4(cr) + H+(aq)
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2HNO3(aq)
Ag2SO4(cr) + H+(aq)
Are elements balanced?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2HNO3(aq)
Ag2SO4(cr) + H+(aq)
Is the charge the same
on both sides of the arrow?
Write in net ionic form
2AgNO3(aq) + H2SO4(aq)
2Ag+(aq) + HSO4-(aq)
Ag2SO4(cr) + 2HNO3(aq)
Ag2SO4(cr) + H+(aq)
This IS the
net ionic equation!
Net Ionic Equations
END