Dr. Williamson’s Notes, Chemical
Reactions Pt 2
CHEMICALEQUATIONS,PART2
Dr.V.M.Williamson
StudentVersion
©vmwilliamson
Whatismel+ng,molten,dissolving??
SolubilityofCommonIonic
CompoundsinWater
Generally Soluble
Exceptions
Na+, K+, NH4+ compounds
Chlorides (Cl–) -----------------Insoluble: AgCl, Hg2Cl2
Bromides (Br–) ----------------Insoluble: AgBr, Hg2Br2, PbBr2
Iodides (I–) ----------------------Insoluble: AgI, Hg2I2, PbI2
Nitrates (NO3–)
Nitrites(NO2–) -------------------Moderately soluble: AgNO2
Chlorates (ClO3–)
Perchlorates (ClO4–)----------Moderately soluble: KClO4
Permanganates (MnO4–)
Acetates (C2H3O2–) -----------Moderately soluble: AgC2H3O2
Sulfates (SO42–) ------------Insoluble: BaSO4, PbSO4, HgSO4
Moderately: CaSO4, SrSO4, Ag2SO4
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
SolubilityofCommonIonic
CompoundsinWater
Generally Insoluble
Sulfides
(S2–)
Exceptions
------------------Soluble: those of NH4+
Na+, K+, Mg2+, Ca2+
Oxides (O2–)
Hydroxides (OH–)
Carbonates (CO32–)
Phosphates (PO43–)
Arsenates (AsO43–)
---Soluble: Li2O, LiOH
Na2O, NaOH, K2O,
KOH, BaO, Ba(OH)2
----Moderately soluble:
CaO, Ca(OH)2 ,
SrO, Sr(OH)2
-----Soluble: those of NH4+
Na+, K+
SOLUBILITY
•  Mostnitratesaltsaresoluble.
•  MostsaltsofNa+,K+,andNH4+aresoluble.
•  Mostchloridesaltsaresoluble.NotableexcepRons
arethoseofAg+,Pb2+,andHg22+
•  Mostsulfateandacetatesaltsaresoluble.Notable
excepRonsarethosesulfatesofBa2+,Pb2+,andCa2+
•  Mosthydroxidecompoundsareslightlysoluble.*
NotableexcepRonsarethoseofNa+&K+.Hydroxides
ofBa2+andCa2+aremoderatelysoluble.
•  Mostsulfide,carbonate,chromate,andphosphate
saltsareonlyslightlysoluble.*Na+,K+,andNH4+are
excepRons.
•  *slightlysoluble=insoluble
WriRngReacRons
•  Howdowepredictifchemicalswillreact?
•  ReacRonsoccurforanumberofreasons.
•  Therearegeneraldrivingforcesthatcause
reacRonstohappen.
•  OnceyouknowthatareacRonwilloccur,you
canwritetheproductformulasandbalance
theequaRons.
•  Remember:balancethe___________and
________last.Leavethe_____________
togetherIFtheyareonbothsides.
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
ReacRon
Driving
Force:
Formation
_________
Copyright © 1995 by Saunders College Publishing
 AgNO3(aq) + NaCl(aq) !__________+ NaNO3(aq)
PrecipitaRonReacRon:Net
IonicEquaRon
  olecularEquaRon
M
 AgNO3(aq)+NaCl(aq)!AgCl(s)+NaNO3(aq)
 CompleteIonicEquaRon
  etIonicEquaRon
N
 
WillTheseReact???
UseSolubilityTables
A=
B=
C=
D=
1.  NaCl(aq)+NaNO3(aq)!
2.  NaCl(aq)+Mg(NO3)2(aq)!
3.  AgNO3(aq)+CaCl2(aq)!
4.  K2CrO4(aq)+Pb(NO3)2(aq)!
3
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
WhataretheProductsforThose
ReacRng???
•  _AgNO3(aq)+CaCl2(aq)!
•  K2CrO4(aq)+Pb(NO3)2(aq)!
Double Replacement, Double Displacement, or
Methathesis Reactions
Molecular,CompleteIonic,Net
IonicEquaRons
  olecularEquaRon
M
 2AgNO3(aq)+CaCl2(aq)!2AgCl(s)+Ca(NO3)2(aq)
 CompleteIonicEquaRon
  etIonicEquaRon
N
 
PrecipitaRonEquaRons
FormulaunitequaRon
  K2CrO4(aq)+Pb(NO3)2(aq)!
PbCrO4(s)+2KNO3(aq)
•  TotalionicequaRon
• 
•  NetionicequaRon
  4
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
DrivingForce:FormaRonofa________
Spectator
ions:
____and
_____
Copyright © 1995 by Saunders College Publishing
NetionicequaRon:
Pb2+(aq)+CrO42-(aq)!
ConducRvity
• 
• 
• 
• 
• 
Recall Demos
Conductivity of Salt
•  NaCl
Conductivity of Sugar
•  C12H22O11
Bonding in each
What is required to
conduct??
See Demo: Conductivity of HCl and HC2H3O2
Dissociation vs Ionization
•  _______________: solid ____ compound
separates into ions in solution
  e.g., NaCl(aq) → Na+(aq) + Cl–(aq)
•  _______________: ________ compound
separates into ions in solution
  e.g., HCl(aq) → H+(aq) + Cl–(aq)
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Electrolytes
" Conduct
electric current due to
presence of ions in solution
 
Strong: good conductors; complete
ionization/dissociation
 
Weak: poor conductors; only slightly
ionized/dissociated
 
Nonelectrolyte: nonconductors; no
ionization/dissociation
Electrolytes
 _________
Electrolyte:
 NaCl
_  _______ Electrolyte:
HC2H3O2 or CH3COOH
_______electrolyte:
C2H5OH
Acids and Bases
•  Operational /Experimental
–  See Demo
•  Arrhenius
–  Acids:________________inaqueoussoluRon
–  Bases:________________inaqueoussoluRon
•  Bronsted-Lowry
–  Acids:_______________________________
–  Bases:_______________________________
•  Lewis- for later
6
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Bronsted-Lowry
• 
acids:
HCl(aq)+H2O(l)!H3O+(aq)+Cl–(aq)
AcidBaseC.AcidC.Base
• 
bases:
NH3(aq)+H2O(l)!NH4+(aq)+OH–(aq)
Base AcidC.Acid C.Base
StrongandWeakAcids
• 
Acids:produce_______inaqueoussoluRon
• 
Strongacids:ionize_______________or
almost__________e.g.,HCl:
HCl(aq)!H+(aq)+Cl–(aq)
• 
Weakacids:ionizeonly______________
e.g.,CH3COOHorHC2H3O2
CH3COOH(aq)H+(aq)+CH3COO–(aq)
Reversible Reaction
StrongandWeakAcids
______ acids:
ionize only slightly
(≤5%)
Copyright © 1995 by Saunders College Publishing
________ acids:
ionize essentially
completely
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
StrongandWeakBases
• 
Bases:produce________inaqueoussoluRon
• 
Strongbases:ionize_________oralmost
________________ e.g.,NaOH:
NaOH(aq)!Na+(aq)+OH–(aq)
• 
Weakbases:ionize_________inaqueous
soluRone.g.,NH3:
NH3(aq)+H2O(l)NH4+(aq)+OH–(aq)
Reversible Reaction
________ bases:
ionize essentially
completely
________ bases:
ionize only slightly
Copyright © 1995 by Saunders College Publishing
StrongandWeakBases
StrongElectrolytes
• 
• 
• 
Strongacids:
HCl,HBr,HI,HNO3,H2SO4,HClO4
(notesomebookslistHClO3,butnotyourbookor
OWL)
HCl(aq)!
Strongbases:
LiOH,KOH,RbOH,CsOH,Ca(OH)2,Sr(OH)2,Ba(OH)2
1stfamilyhydroxides,2ndfamilyhydroxidesexcept
BeandMg.
Ba(OH)2(aq)!
Solublesalts:
UseSolubilitytable
NH4ClO4(aq)!
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
WeakElectrolytes
Weakacids(notonlistofstrong)
CH3COOH(aq)<-->H+(aq)+CH3COO–(aq)
•  Weakbases(notonlistofstrong)
• 
NH3(aq)+H2O(l)<-->NH4+(aq)+OH–(aq)
• 
Insolubleorsparinglysolubleacids/bases
All _____________ Reactions
Electrolytes
 __________:
 _________:
CH3COOH
 __________:
C2H5OH
Copyright © 1995 by Saunders College Publishing
HCl
•  WhichofthefollowingaqueoussoluRonswill
conductelectricitymosteffecRvely??
•  (A)0.50M________(B)0.50M____
(C)0.50M________ (D)allareequal
•  Whichwillconductelectricityleast
effecRvely??
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Acid-BaseReacRons
DrivingForce:FormaRonof________
• 
StrongAcidwithStrongBase:
HNO3(aq)+NaOH(aq)!
CompleteIonic:
Net:
Acid-BaseReacRons
• 
WeakAcidwithStrongBase:
Ba(OH)2(aq)+2HC2H3O2(aq)!
Ba(C2H3O2)2(aq)+2H2O(l)
CompleteIonic:
Net:
DrivingForce:FormaRonof_____
•  Whatare________?
– H2,O2,N2,F2,Cl2,+8thfamily
– CO2,NH3,SO2,H2S
•  TreatasdoubledisplacementreacRons,
butifaproductshouldbethefollowing
changeittotheproducts:
– H2CO3!H2O(l)+CO2(g)
– H2SO3!H2O(l)+SO2(g)
– NH4OH!H2O(l)+NH3(g)
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
GasFormingReacRon
Copyright © 1995 by Saunders College Publishing
DrivingForce:GasFormaRon
equaRon
  HC2H3O2(aq)+NaHCO3(s)!
NaC2H3O2(aq)+H2CO3(aq)
•  ActualequaRon
  HC2H3O2(aq)+NaHCO3(s)!
NaC2H3O2(aq)+___________________
• 
Copyright © 1995 by Saunders College Publishing
DrivingForce?
!
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
DrivingForce:TransferofElectrons
_____ of electrons
2Ag+(aq)+Cu(s)! 2Ag(s) + Cu2+(aq)
_____ of electrons
loss of electrons is ____________ (____)
gain of electrons is ____________ (_____)
Ag+ is reduced: it is the __________ agent
Cu is oxidized: it is the __________ agent
Oxidation and reduction occur
simultaneously
Electrons are __________in a redox reaction
OxidaRonNumber
• 
• 
• 
• 
• 
MechanicalaidinwriRngformulasand
balancingequaRons
Indicatestheoxida3onstateoftheelement
inthecompound
CommonlyreferredtoasO.N.
Representedas+n,–nwhileioniccharges
aren+andn–
Note:oxidaRonstatemaynotreallyexistin
molecule
AssignmentofOxida+onNumbers
• 
• 
• 
• 
• 
• 
• 
Forfreeelement:O.N.=____(ZnorH2)
Formonatomicion:O.N.=____________(Na1+)
Forpolyatomicions:sumofO.N.of
consRtuentatoms=___________ofion(OH1-)
Inmostcompounds:O.N.forH=____(ex.NaH)
O.N.forO=____(ex.H2O2)
ForFincompounds:O.N.=______
ForCl,Br,Iincompounds:O.N.=______,unless
combinedwithOorF
SumofallO.N.inacompound=__
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Oxida+onNumbers
Examples
• 
• 
• 
H3PO4: O.N.P:____
MnO4–: O.N.Mn:____
Cr2O72–: O.N.Cr:____
• 
• 
C7H8: O.N.C:____
NO3–: O.N.N:____
• 
• 
NO2–: O.N.N:____
NO–: O.N.N:____
AcRvitySeriesofSomeElements
MetalsCommon OxidizedFormNonmetals
LiLi+F2 MOST Reactive
KK+O2
CaCa2+Cl2
NaNa+
MgMg2+Br2
AlAl3+
ZnZn2+I2
NiNi2+
HH+
SbSb3+
CuCu+,Cu2+
HgHg22+,Hg2+
AgAg+
LEAST Reactive
PtPt2+,Pt4+
Displacement Reactions
Copyright © 1995 by Saunders College Publishing
 Mg(s)
+ 2HCl(aq) !
Active Metal +
Salt of Less Active Metal
Less Active Metal +
Salt of More Active Metal
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
DisplacementReac+ons
Active Metal
+
Nonoxidizing
Acid
Hydrogen +
Salt of Acid
Zn(s)+H2SO4(aq)!ZnSO4(aq)+H2(g)
Zn(s)+2H+(aq)+SO42–(aq)!
Zn2+(aq)+SO42–(aq)+H2(g)
Net: DisplacementReac+ons
Active NonMetal + Salt of Less Active Nonmetal
Less Active NonMetal + Salt of More Active Nonmetal
Cl2(g)+2NaBr(aq)! 2NaCl(aq)+Br2(l)
Cl2(g)+2Na+(aq)+2Br–(aq)!
2Na+(aq)+2Cl–(aq)+Br2(l)
Net: Activity order: I2 < Br2 < Cl2 < F2
SingleDisplacementReacRons
InvolveoxidaRonsandreducRons
Involvedisplacementofoneelement(froma
compound)byanotherelement:
CuSO4(aq)+Zn(s)!Cu(s)+ZnSO4(aq)
Zn(s)+H2SO4(aq)!ZnSO4(aq)+H2(g)
•  The_____acRvemetaldisplacesthe___acRve
metalorhydrogen
•  Themoreeasilyoxidizedmetalisthemore
acRveone
• 
• 
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Dr. Williamson’s Notes, Chemical
Reactions Pt 2
RedoxReacRons
_________
Reactions
Copyright © 1995 by Saunders College Publishing
 2Fe(s)
+ 3Cl2(g) ! 2FeCl3(s)
Decomposition of
Hydrogen Peroxide
Copyright © 1995 by Saunders College Publishing
 2H2O2(aq)
! 2H2O(l) + O2(g)
Redox Reactions: Decomposition of Hydrogen Peroxide
_______
 2H2O2(aq)
! 2H2O(l) + O2(g)
________
The same element (O) is
oxidized and reduced
15
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Redox Reactions: Combustion of Methane
________e-
Oxidized
 CH4(g)
+ 2O2(g) ! 2H2O(l) + CO2(g)
Reduced
________e-
Note: Driving Forces include transfer of
electrons, formation of ___________, AND
formation of a __________
A =
• 
B=
C=
D=
E=
(1)3Ag+(aq)+PO43–(aq)!Ag3PO4(s)
• 
(2)HgCl2(aq)+2KI(aq)!HgI2(s)+2KCl(aq)
• 
(3)3Zn(s)+2CoCl3(aq)! 3ZnCl2(aq)+2Co(s)
• 
(4)2H2(g)+O2(g)!2H2O(l)
TypesofChemicalReac+ons
Chemical
Reac+ons
___________
Redox
__________
____________
rxns
rxns
rxns
rxns
_______
______________
rxns
__________
____________
___________
rxns
rxns
rxns
16
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
TypesofReacRons
inAqueousSoluRons
• 
• 
• 
• 
Acid-Base:formaRonof_______
(transferofH+fromacidtobase)
PrecipitaRon:formaRonof_______(an
insolubleproductorprecipitate)
OxidaRon-reducRon:transferof_______
fromonespeciestoanother
Gas-forming:formaRonof______
Blue = Driving Forces
EvidenceofaChemicalReacRon
EquaRons
Zn(s)+Cu(NO3)2(aq)!
Cu(s)+Zn(NO3)2(aq)!
NaCl(aq)+AgNO3(aq)!
NH4NO3(s)+Ba(OH)2(s)!
NaHCO3(s)+HC2H3O2(aq)!
KSCN(aq)+Fe(NO3)3(aq)!
Mg(s)+O2(g)!
EvidenceofChemicalChange
• 
• 
• 
• 
Formation of Gas
Formation of a ppt
Color change
Energy or Temperature
Change
•  Change in mass IF the
system is open
17
Dr. Williamson’s Notes, Chemical
Reactions Pt 2
Put‘NR’ifnoreacRonshouldoccur.Givethe
completebalancedequaRon,thenetionicequaRon
andthedrivingforceforreacRonsthatdooccur.
• 
• 
• 
• 
• 
• 
• 
• 
a). KOH(aq)+H2SO4(aq)!,
b.)Pb(s)+Cu(NO3)2(aq)!
c.) BaCl2(aq)+H2SO4(aq)!
d.)C4H8(g)+O2(g,excess)!
e.)BaCl2(aq)+HNO3(aq)!
f.) ZnO(s)heat>
g.) HClO3(aq)+LiOH(aq)!
h.)Ni(s)+FeCl2(aq)!
See answers under
‘frequently asked
questions’ on the
homepage
18