Chapter15 ExtraCredit Name:______________Key_______________

1.Writetheionicequationfordissolutionandthesolubilityproduct(Ksp)expressionforeachofthefollowingslightlysolubleioniccompounds:

(a)PbCl2PbCl2(s)⇄Pb2+(aq)+2Cl−(aq)Ksp=[Pb2+][Cl−]2

2.Usesolubilityproductsandpredictwhichofthefollowingsaltsisthemostsoluble,intermsofmolesperliter,inpurewater:CaF2,Hg2Cl2,PbI2,orSn(OH)2.

CaF2 Ksp=4.0x10−11

Hg2Cl2 Ksp=1.1x10−18

PbI2 Ksp=1.4x10−8

Sn(OH)2 Ksp=3x10−27

Eachofthesebreakintoatotalof3ions(evenmercury(I)chloride)sotheKsp’scanbedirectlycompared,

Sn(OH)2islesssolublethanHg2Cl2<CaF2<PbI2

3.Calculatethemolarsolubilityofeach.LookupKspintheappendix.

(a)PbI2 Ksp=1.4x10−8 X=0.0015M

(b)Ag2SO4 Ksp=1.2x10−5 X=0.014M

4.Giventhemolarsolubility,calculateKspforeachoftheslightlysolublesolidsindicated:

(a)AgBr:x=5.7×10–7M,Ksp=x2 Ksp=3.2x10−13

(b)PbF2:x=2.1×10–3M,Ksp=x(2x)2Ksp=3.7x10−8

5.TheHandbookofChemistryandPhysicsgivessolubilitiesofthefollowingcompoundsingramsper100mLofsolution.Calculatethesolubilityproduct(Ksp)foreach.

(a)BaSiF6,0.026g/100mL(containsSiF62−)x=0.00074MKsp=5.5x10−7

(b)Ce(IO3)4,1.5×10–2g/100mLMMCe(IO3)4=840g/mole

X=0.00018MKsp=[Ce4+][IO3−]4=x(4x)4=256(x)5

Ksp=4.8x10−17

5.Calculatethemolarsolubilityof:

(a)AgCl(s)inpurewater.Ksp=1.6x10−10 x=1.3x10−5M

AgCl(s)in0.010MNaCl x=1.6x10−8M

Howdoesthesolubilitychangewhenacommonionisadded?Thesolubilitydecreases.

(b)Calculatethemolarsolubilityof:CaF2(s)in0.00125MKFKsp=4.0x10−11=[Ca2+][F−]2=x(.00125+2x)2=x(.00125)2

x=2.6x10−6M

(c)Calculatethemolarsolubilityof:Ni(OH)2(s)inasolutionwithpHof12.00.Ksp=1.6x10−16

[OH−]=10−2Ksp=[Ni2+][OH−]2=(x)(.01+2x)2=x(.01)2x=1.6x10−12M

7.Willaprecipitateformgiventheconcentrationsindicated?(SeeappendixforKspvalues.)

(a)CaCO3:[Ca2+]=0.0020M,[CO32−]=0.010MKsp=8.7x10−9

Q=2.0x10−5Q>Ksp,soaprecipitatewillform.

(b)Mn(OH)2:[Mn2+]=1.0×10–4M,[OH–]=1.0×10–5M

Q=1.0x10−14Q<Ksp,aprecipitatewillnotform.

8.DrawtheLewisStructureforeachandLabeltheLewisAcidsandtheLewisBases(reactantsonly)(a)BF3+F−⟶ BF4−

LALB(b)Al(OH)3+OH−⟶ Al(OH)4−

LALB

DrawtheLewisStructureforeachandLabeltheLewisAcidsandtheLewisBases(reactantsonly)andpredicttheProducts.(a)NH3(g)+HCl(g)⟶

LB LA(b)NH4

++C2H5O− ⟶LALB

9.Avolumeof.080Lof2.0x10−3MBa(NO3)2(aq)isaddedto.020Lof5.0x10−3MLi2SO4(aq).Willaprecipitateform?

For:BaSO4:Ksp=2.3x10−8

Q=1.6x10−6.Aprecipitatewillform.