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Reactions in Aqueous Solution
Chapter 4
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A _______________ is a homogenous mixture of 2
or more substances
The __________ is(are) the substance(s) present in
the smaller amount(s)
The _____________ is the substance present in the
larger amount
Solution
Solvent
Solute(s)
Soft drink (l)
H2O
Sugar, CO2
Air (g)
N2
O2, Ar, CH4
Soft Solder (s)
Pb
Sn
4.1
An ___________ is a substance that, when dissolved in
water, results in a solution that can conduct electricity.
A _____________ is a substance that, when dissolved,
results in a solution that does not conduct electricity.
______________
______________
______________
4.1
Conduct electricity in solution?
__________ (+) and __________(-)
Strong Electrolyte – _______% dissociation
NaCl (s)
H 2O
Na+ (aq) + Cl- (aq)
Weak Electrolyte – _________________________
CH3COOH
CH3COO- (aq) + H+ (aq)
4.1
_________ is the process in which an ion is surrounded
by water molecules arranged in a specific manner.
d-
d+
H2O
_______________ does not conduct electricity
No cations (+) and anions (-) in solution
C6H12O6 (s)
H 2O
C6H12O6 (aq)
______________
______________
______________
HCl
CH3COOH
(NH2)2CO
HNO3
HF
CH3OH
HClO4
HNO2
C2H5OH
NaOH
H2O
C12H22O11
Ionic Compounds
4.1
Precipitation Reactions
____________–insoluble solid that separates from solution
precipitate
Pb(NO3)2 (aq) + 2NaI (aq)
PbI2 (s) + 2NaNO3 (aq)
________________________
Pb2+ + 2NO3- + 2Na+ + 2I-
PbI2 (s) + 2Na+ + 2NO3-
________________________
Pb2+ + 2IPbI2
PbI2 (s)
________________________
Na+ and NO3- are ____________ ions
4.2
Writing Net Ionic Equations
1. Write the balanced molecular equation.
2. Write the ionic equation showing the strong electrolytes
3. Determine precipitate from solubility rules
4. Cancel the spectator ions on both sides of the ionic equation
Write the net ionic equation for the reaction of silver
nitrate with sodium chloride.
AgNO3 (aq) + NaCl (aq)
AgCl (s) + NaNO3 (aq)
4.2
Solubility Rules for Common Ionic Compounds
In water at 250C
Soluble Compounds
Exceptions
Compounds containing alkali
metal ions and NH4+
NO3-, HCO3-, ClO3Cl-, Br-, ISO4
2-
Halides of Ag+, Hg22+, Pb2+
Sulfates of Ag+, Ca2+, Sr2+, Ba2+,
Hg2+, Pb2+
Insoluble Compounds
Exceptions
CO32-, PO43-, CrO42-, S2-
Compounds containing alkali
metal ions and NH4+
OH-
Compounds containing alkali
metal ions and Ba2+
Memorize!
4.2
Acids
Have a sour taste. Vinegar owes its taste to acetic acid.
Citrus fruits contain citric acid.
React with certain metals to produce hydrogen gas.
React with carbonates and bicarbonates to produce carbon
dioxide gas
Bases
Have a bitter taste.
Feel slippery. Many soaps contain bases.
4.3
_________ acid is a substance that produces H+ (H3O+) in water
_________ base is a substance that produces OH- in water
4.3
A __________ acid is a proton donor
A __________ base is a proton acceptor
base
acid
acid
base
A __________ acid must contain at
least one ionizable proton!
4.3
______________ acids
HCl
H+ + Cl-
HNO3
CH3COOH
H+ + NO3H+ + CH3COO-
Strong electrolyte, strong acid
Strong electrolyte, strong acid
Weak electrolyte, weak acid
______________ acids
H2SO4
H+ + HSO4-
Strong electrolyte, strong acid
HSO4-
H+ + SO42-
Weak electrolyte, weak acid
______________ acids
H3PO4
H2PO4HPO42-
H+ + H2PO4H+ + HPO42H+ + PO43-
Weak electrolyte, weak acid
Weak electrolyte, weak acid
Weak electrolyte, weak acid
4.3
___________________ Reaction
acid + base
_________ + ________ + ________
All _________ are strong electrolytes.
HCl (aq) + NaOH (aq)
H+ + Cl- + Na+ + OH-
H+ + OH-
NaCl (aq) + H2O
Na+ + Cl- + H2O
H2O
4.3
Oxidation-Reduction Reactions
(electron transfer reactions)
2Mg (s) + O2 (g)
2Mg
O2 + 4e-
2MgO (s)
2Mg2+ + 4e- ________ half-reaction (lose e-)
2O2-
________ half-reaction (gain e-)
2Mg + O2 + 4e2Mg + O2
2Mg2+ + 2O2- + 4e2MgO
4.4
Zn (s) + CuSO4 (aq)
Zn
ZnSO4 (aq) + Cu (s)
Zn2+ + 2e- Zn is ________ Zn is the ________ agent
Cu2+ + 2e-
Cu Cu2+ is _______ Cu2+ is the _______ agent
4.4
Copper wire reacts with silver nitrate to form silver metal.
What is the oxidizing agent in the reaction?
Cu (s) + 2AgNO3 (aq)
Cu
Ag+ + 1e-
Cu(NO3)2 (aq) + Ag (s)
Cu2+ + 2eAg Ag+ is ________ Ag+ is the _____________
4.4
Oxidation number
The charge the atom would have in a molecule (or an
ionic compound) if electrons were completely transferred.
1. Free elements (uncombined state) have an oxidation
number of zero.
Na, Be, K, Pb, H2, O2, P4 = 0
2. In monatomic ions, the oxidation number is equal to
the charge on the ion.
Li+, Li = +1; Fe3+, Fe = +3; O2-, O = -2
3. The oxidation number of oxygen is usually –2. In H2O2
and O22- it is –1.
4.4
4. The oxidation number of hydrogen is +1 except when
it is bonded to metals in binary compounds. In these
cases, its oxidation number is –1.
5. Group IA metals are +1, IIA metals are +2 and fluorine is
always –1.
6. The sum of the oxidation numbers of all the atoms in a
molecule or ion is equal to the charge on the
molecule or ion.
HCO3Oxidation numbers of all
the atoms in HCO3- ?
O=
H=
3x-2 + 1 + ? = -1
C=
4.4
IF7
Oxidation numbers of all
the atoms in the
following ?
F=
7x-1 + ? = 0
I=
K2Cr2O7
NaIO3
Na =
O=
3x-2 + 1 + ? = 0
I=
O=
K=
7x-2 + 2x+1 + 2x? = 0
Cr =
4.4
Types of Oxidation-Reduction Reactions
Reaction
A+B
C
0
+4 -2
0
S + O2
SO2
Reaction
C
+1 +5 -2
2KClO3
A+B
+1 -1
0
2KCl + 3O2
4.4
Types of Oxidation-Reduction Reactions
Reaction
A + BC
0
+1
+2
Sr + 2H2O
+4
0
TiCl4 + 2Mg
0
AC + B
-1
Cl2 + 2KBr
0
Sr(OH)2 + H2 Hydrogen Displacement
0
+2
Ti + 2MgCl2
-1
Metal Displacement
0
2KCl + Br2
Halogen Displacement
4.4
The Activity Series for Metals
Displacement Reaction
M + BC
AC + B
M is metal
BC is acid or H2O
B is H2
Ca + 2H2O
Ca(OH)2 + H2
Pb + 2H2O
Pb(OH)2 + H2
4.4
Types of Oxidation-Reduction Reactions
Reaction
Element is simultaneously oxidized and reduced.
0
Cl2 + 2OH-
+1
-1
ClO- + Cl- + H2O
Chlorine Chemistry
4.4
Classify the following reactions.
Ca2+ + CO32NH3 + H+
Zn + 2HCl
Ca + F2
CaCO3
NH4+
ZnCl2 + H2
CaF2
__________________
__________________
__________________
__________________
4.4
Solution Stoichiometry
The ________________ of a solution is the amount of
solute present in a given quantity of solvent or solution.
M = ____________ =
moles of solute
liters of solution
4.5
Solution Stoichiometry
What mass of KI is required to make 500 mL of
a 2.80 M KI solution?
M KI
volume KI
moles KI
M KI
grams KI
1L
2.8 mol KI 166 g KI
x
500 mL x
= _____ g KI
x
1000 mL
1 L soln
1 mol KI
4.5
4.5
________________ is the procedure of
preparing a less concentrated solution
from a more concentrated solution.
Dilution
Add Solvent
Moles of solute
before dilution (i)
=
Moles of solute
after dilution (f)
MiVi
=
MfVf
4.5
How would you prepare 60.0 mL of 0.200 M
HNO3 from a stock solution of 4.00 M HNO3?
MiVi = MfVf
Mi = 4.00
Vi =
Mf = 0.200
MfVf
Mi
=
Vf = 0.06 L
Vi = ? L
=
4.5
Gravimetric Analysis
1. Dissolve unknown substance in water
2. React unknown with known substance to form a precipitate
3. Filter and dry precipitate
4. Weigh precipitate
5. Use chemical formula and mass of precipitate to determine
amount of unknown ion
4.6
___________________
In a _____________________ a solution of accurately known
concentration is added gradually added to another solution of
unknown concentration until the chemical reaction between the
two solutions is complete.
________________ – the point at which the reaction is complete
_______________ – substance that changes color at (or near)
the equivalence point
Slowly add base
to unknown acid
UNTIL
The indicator
changes color
(pink)
4.7
What volume of a 1.420 M NaOH
solution is required to titrate 25.00 mL
of a 4.50 M H2SO4 solution?
BALANCE THE CHEMICAL EQUATION!
H2SO4 + NaOH
M
volume acid
acid
H2O + Na2SO4
rx
moles acid
coef.
M
moles base
base
volume base
4.7
What volume of a 1.420 M NaOH solution is
Required to titrate 25.00 mL of a 4.50 M H2SO4
solution?
BALANCE THE CHEMICAL EQUATION!
H2SO4 + 2NaOH
M
volume acid
25 mL x
acid
2H2O + Na2SO4
rx
moles acid
4.50 mol H2SO4
1000 mL soln
x
coef.
M
moles base
2 mol NaOH
1 mol H2SO4
x
base
volume base
1000 ml soln
= _____ mL
1.420 mol NaOH
4.7
(4.72 p.120) What volume of a 0.500 M KOH
solution is required to titrate 10.0 mL of a
0.20 M H2SO4 solution?
H2SO4 + KOH
H2O + K2SO4
M
volume acid
10.0 mL x
acid
rx
moles acid
___ mol H2SO4
____ mL soln
x
coef.
M
moles base
__ mol KOH
__ mol H2SO4
x
base
volume base
____ ml soln
____ mol KOH
= ___ mL
4.7
(4.72 p.120) What volume of a 0.500 M KOH
solution is required to titrate 10.00 mL of a
0.20 M H2SO4 solution?
H2SO4 + 2KOH
2H2O + Na2SO4
M
volume acid
10.0 mL x
acid
rx
moles acid
0.20 mol H2SO4
1000 mL soln
x
coef.
M
moles base
2 mol KOH
1 mol H2SO4
x
base
volume base
1000 ml soln
0.500 mol KOH
= _____ mL
4.7