Dr. Williamson’s Notes, Chemical Reactions Pt 2

1

CHEMICALEQUATIONS,PART2

Dr.V.M.WilliamsonStudentVersion

©vmwilliamson

Whatismel+ng,molten,dissolving??

SolubilityofCommonIonicCompoundsinWater

Generally Soluble ExceptionsNa+, K+, NH4

+ compoundsChlorides (Cl–) -----------------Insoluble: AgCl, Hg2Cl2 Bromides (Br–) ----------------Insoluble: AgBr, Hg2Br2, PbBr2

Iodides (I–) ----------------------Insoluble: AgI, Hg2I2, PbI2Nitrates (NO3

–) Nitrites(NO2

–) -------------------Moderately soluble: AgNO2Chlorates (ClO3

–) Perchlorates (ClO4

–)----------Moderately soluble: KClO4Permanganates (MnO4

–)Acetates (C2H3O2

–) -----------Moderately soluble: AgC2H3O2Sulfates (SO4

2–) ------------Insoluble: BaSO4, PbSO4, HgSO4 Moderately: CaSO4, SrSO4, Ag2SO4

SolubilityofCommonIonicCompoundsinWater

Generally Insoluble Exceptions

Sulfides (S2–) ------------------Soluble: those of NH4+

Na+, K+, Mg2+, Ca2+

---Soluble: Li2O, LiOHOxides (O2–) Na2O, NaOH, K2O,Hydroxides (OH–) KOH, BaO, Ba(OH)2 ----Moderately soluble:

CaO, Ca(OH)2 , SrO, Sr(OH)2

Carbonates (CO32–)

Phosphates (PO43–) -----Soluble: those of NH4

+ Arsenates (AsO4

3–) Na+, K+

SOLUBILITY•  Mostnitratesaltsaresoluble.•  MostsaltsofNa+,K+,andNH4

+aresoluble.•  Mostchloridesaltsaresoluble.NotableexcepRonsarethoseofAg+,Pb2+,andHg22+

•  Mostsulfateandacetatesaltsaresoluble.NotableexcepRonsarethosesulfatesofBa2+,Pb2+,andCa2+

•  Mosthydroxidecompoundsareslightlysoluble.*NotableexcepRonsarethoseofNa+&K+.HydroxidesofBa2+andCa2+aremoderatelysoluble.

•  Mostsulfide,carbonate,chromate,andphosphatesaltsareonlyslightlysoluble.*Na+,K+,andNH4

+areexcepRons.

•  *slightlysoluble=insoluble

WriRngReacRons•  Howdowepredictifchemicalswillreact?•  ReacRonsoccurforanumberofreasons.

•  TherearegeneraldrivingforcesthatcausereacRonstohappen.

•  OnceyouknowthatareacRonwilloccur,youcanwritetheproductformulasandbalancetheequaRons.

•  Remember:balancethe___________and________last.Leavethe_____________togetherIFtheyareonbothsides.

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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ReacRon

 AgNO3(aq) + NaCl(aq) !__________+ NaNO3(aq) Copyright © 1995 by Saunders College Publishing

Driving Force:

Formation _________

PrecipitaRonReacRon:NetIonicEquaRon

 MolecularEquaRon  AgNO3(aq)+NaCl(aq)!AgCl(s)+NaNO3(aq)

 CompleteIonicEquaRon

 NetIonicEquaRon  

WillTheseReact???UseSolubilityTables

1.  NaCl(aq)+NaNO3(aq)!

2.  NaCl(aq)+Mg(NO3)2(aq)!3.  AgNO3(aq)+CaCl2(aq)!

4.  K2CrO4(aq)+Pb(NO3)2(aq)!

A = B = C= D=

WhataretheProductsforThoseReacRng???

•  AgNO3(aq)+CaCl2(aq)!

•  K2CrO4(aq)+Pb(NO3)2(aq)!

_

Double Replacement, Double Displacement, or Methathesis Reactions

Molecular,CompleteIonic,NetIonicEquaRons

 MolecularEquaRon  2AgNO3(aq)+CaCl2(aq)!2AgCl(s)+Ca(NO3)2(aq)

 CompleteIonicEquaRon

 NetIonicEquaRon  

PrecipitaRonEquaRons

•  FormulaunitequaRon   K2CrO4(aq)+Pb(NO3)2(aq)!

PbCrO4(s)+2KNO3(aq)•  TotalionicequaRon

•  NetionicequaRon  

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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DrivingForce:FormaRonofa________

NetionicequaRon:Pb2+(aq)+CrO4

2-(aq)!

Copyright © 1995 by Saunders College Publishing

Spectator ions: ____and _____

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)

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: C2H5OH

 ________ Electrolyte: HC2H3O2 or CH3COOH

 _________ Electrolyte:  NaCl

Acids and Bases•  Operational /Experimental

– See Demo•  Arrhenius

– Acids:________________inaqueoussoluRon– Bases:________________inaqueoussoluRon

• Bronsted-Lowry– Acids:_______________________________– Bases:_______________________________

•  Lewis- for later

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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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_______________oralmost__________e.g.,HCl:HCl(aq)!H+(aq)+Cl–(aq)

•  Weakacids:ionizeonly______________e.g.,CH3COOHorHC2H3O2CH3COOH(aq)H+(aq)+CH3COO–(aq)

Reversible Reaction

StrongandWeakAcids

________ acids: �ionize essentially

completely ���

______ acids: �ionize only slightly �

(≤5%)

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StrongandWeakBases

•  Bases:produce________inaqueoussoluRon

•  Strongbases:ionize_________oralmost________________ e.g.,NaOH:NaOH(aq)!Na+(aq)+OH–(aq)

•  Weakbases:ionize_________inaqueoussoluRone.g.,NH3:

NH3(aq)+H2O(l)NH4+(aq)+OH–(aq)

Reversible Reaction

StrongandWeakBases

________ bases: �ionize essentially

completely �

________ bases: �ionize only slightly

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StrongElectrolytes•  Strongacids: HCl,HBr,HI,HNO3,H2SO4,HClO4(notesomebookslistHClO3,butnotyourbookorOWL)

HCl(aq)!

•  Strongbases: LiOH,KOH,RbOH,CsOH,Ca(OH)2,Sr(OH)2,Ba(OH)21stfamilyhydroxides,2ndfamilyhydroxidesexceptBeandMg.

Ba(OH)2(aq)!

•  Solublesalts:UseSolubilitytableNH4ClO4(aq)!

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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WeakElectrolytes

•  Weakacids(notonlistofstrong)CH3COOH(aq)<-->H+(aq)+CH3COO–(aq)

•  Weakbases(notonlistofstrong)

NH3(aq)+H2O(l)<-->NH4+(aq)+OH–(aq)

•  Insolubleorsparinglysolubleacids/bases

All _____________ Reactions

Electrolytes

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 _________: CH3COOH

 __________: HCl

 __________: C2H5OH

•  WhichofthefollowingaqueoussoluRonswillconductelectricitymosteffecRvely??

•  (A)0.50M________(B)0.50M____(C)0.50M________ (D)allareequal

•  WhichwillconductelectricityleasteffecRvely??

Acid-BaseReacRonsDrivingForce: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,butifaproductshouldbethefollowingchangeittotheproducts:– H2CO3!H2O(l)+CO2(g)– H2SO3!H2O(l)+SO2(g)– NH4OH!H2O(l)+NH3(g)

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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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)+___________________

DrivingForce?

!

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DrivingForce:TransferofElectrons

2Ag+(aq)+Cu(s)! 2Ag(s) + Cu2+(aq)

loss of electrons is ____________ (____) gain of electrons is ____________ (_____)

Ag+ is reduced: Cu is oxidized:

Oxidation and reduction occur simultaneously �

Electrons are __________in a redox reaction

_____ of electrons

_____ of electrons

it is the __________ agent it is the __________ agent

OxidaRonNumber

•  MechanicalaidinwriRngformulasandbalancingequaRons

•  Indicatestheoxida3onstateoftheelementinthecompound

•  CommonlyreferredtoasO.N.•  Representedas+n,–nwhileionicchargesaren+andn–

•  Note:oxidaRonstatemaynotreallyexistinmolecule

AssignmentofOxida+onNumbers

•  Forfreeelement:O.N.=____(ZnorH2)•  Formonatomicion:O.N.=____________(Na1+)

•  Forpolyatomicions:sumofO.N.ofconsRtuentatoms=___________ofion(OH1-)

•  Inmostcompounds:O.N.forH=____(ex.NaH) O.N.forO=____(ex.H2O2)

•  ForFincompounds:O.N.=______

•  ForCl,Br,Iincompounds:O.N.=______,unlesscombinedwithOorF

•  SumofallO.N.inacompound=__

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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Oxida+onNumbersExamples

•  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+F2KK+O2CaCa2+Cl2NaNa+MgMg2+Br2AlAl3+ZnZn2+I2NiNi2+HH+SbSb3+CuCu+,Cu2+HgHg22+,Hg2+AgAg+PtPt2+,Pt4+

MOST Reactive

LEAST Reactive

Displacement Reactions

 Mg(s) + 2HCl(aq) ! Copyright © 1995 by Saunders College Publishing

Active Metal + Salt of Less Active Metal

Less Active Metal + Salt of More Active Metal

Zn(s)+H2SO4(aq)!ZnSO4(aq)+H2(g)

Zn(s)+2H+(aq)+SO42–(aq)!

Zn2+(aq)+SO42–(aq)+H2(g)

Net:

DisplacementReac+ons

Active Metal +

Nonoxidizing Acid

Hydrogen +

Salt of Acid

DisplacementReac+ons

Cl2(g)+2NaBr(aq)! 2NaCl(aq)+Br2(l)

Cl2(g)+2Na+(aq)+2Br–(aq)!

2Na+(aq)+2Cl–(aq)+Br2(l)

Net:

Active NonMetal + Salt

of Less Active Nonmetal

Less Active NonMetal + Salt of More Active

Nonmetal

Activity order: I2 < Br2 < Cl2 < F2

SingleDisplacementReacRons•  InvolveoxidaRonsandreducRons•  Involvedisplacementofoneelement(fromacompound)byanotherelement:

CuSO4(aq)+Zn(s)!Cu(s)+ZnSO4(aq)

Zn(s)+H2SO4(aq)!ZnSO4(aq)+H2(g)

•  The_____acRvemetaldisplacesthe___acRvemetalorhydrogen

•  ThemoreeasilyoxidizedmetalisthemoreacRveone

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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RedoxReacRons

 2Fe(s) + 3Cl2(g) ! 2FeCl3(s)

Copyright © 1995 by Saunders College Publishing

_________ Reactions

Decomposition of �Hydrogen Peroxide

 2H2O2(aq) ! 2H2O(l) + O2(g) Copyright © 1995 by Saunders College Publishing

Redox Reactions:

 2H2O2(aq) ! 2H2O(l) + O2(g)

_______

________

The same element (O) is oxidized and reduced

Decomposition of Hydrogen Peroxide

Redox Reactions:

 CH4(g) + 2O2(g) ! 2H2O(l) + CO2(g)

Oxidized

Reduced________e-

________e-

Combustion of Methane

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

___________

rxns

Redox

rxns

_______

______________

rxns

__________

rxns

____________

rxns

___________

rxns

__________

rxns

____________

rxns

Dr. Williamson’s Notes, Chemical Reactions Pt 2

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TypesofReacRonsinAqueousSoluRons

•  Acid-Base:formaRonof_______(transferofH+fromacidtobase)

•  PrecipitaRon:formaRonof_______(aninsolubleproductorprecipitate)

•  OxidaRon-reducRon:transferof_______fromonespeciestoanother

•  Gas-forming:formaRonof______

Blue = Driving Forces

EvidenceofaChemicalReacRonEquaRons

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

Put‘NR’ifnoreacRonshouldoccur.GivethecompletebalancedequaRon,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)!

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