Single and Double Replacement Reactions

Double-replacement reaction

CaCO3 + 2 HCl CaCl2 + H2CO3

General form: AB + CD AD + CB

Single-replacement reaction

Mg + CuSO4 MgSO4 + Cu

General form: A + BC AC + B

Ca

Activity Series

Foiled again –Foiled again –Aluminum loses to CalciumAluminum loses to Calcium

Element Reactivity

LiRbKBaCaNaMgAlMnZnCrFeNiSnPbH2

CuHgAgPtAu

Halogen Reactivity

F2

Cl2Br2

I2

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ofActivitySeries

Activity Series of the elements

• Activity series – list of elements organized according to the ease with which the elements undergo certain chemical reactions.

• Used to predict if a reaction will take place• For metals – greater activity means loss of

electrons• For nonmetals – greater activity means

ease to gain electrons

• Order of listing is usually determined by single-replacement reactions

• Most active element is placed at the top of the series

• An element can replace any element below it on the series

• An element cannot replace any element above it on the series

Double Replacement

Double replacement – ions of two compounds exchange places in an aqueous solution to form two new compounds

AX + BY AY + BX

FeS + 2HCl H2S + FeCl2

Types of Double Replacement Reactions

1. Formation of a precipitate

2. Formation of a gas

3. Formation of water

Potassium reacts with Water

P O W !P O W !

Mg + AlCl3

Al + MgCl2

Predict if these reactions will occur

Al + MgCl2

Can magnesium replace aluminum?

Activity Series

YES, magnesium is more reactive than aluminum.

2 23 3

Can aluminum replace magnesium?

Activity Series

NO, aluminum is less reactive than magnesium.

Therefore, no reaction will occur.

No reaction

MgCl2 + Al No reaction

The question we must ask is can the single element replace its counterpart? metal replaces metal or nonmetal replaces nonmetal.

Order of reactants DOES NOT

determine how they react.

Single-Replacement Reactions

FeCl2 + Cu

MgBr2 + Cl2

“Magic blue-earth”

Zinc in nitric acid2

A + BC AC + BGeneral Form

Zn(NO3)2 + H2

Can Fe replace Cu? Yes

LiRbKBaCaNaMgAlMnZnCrFeNiSnPbH2

CuHgAgPtAu

F2

Cl2Br2

I2

Can Zn replace H? Yes

Can Br replace Cl? No

NO REACTION

Fe + CuCl2

Zn + HNO3

MgCl2 + Br2

Activity Series

Double Replacement Reaction

K2CO3 (aq)Potassium carbonate

BaCl2 (aq)Barium chloride

2 KCl (aq)Potassium chloride

BaCO3 (s)Barium carbonate

+ +

TABLE OF SOLUBILITIES IN WATER

aluminum s aq n s n s aq aq s aq dammonium aq aq aq aq aq aq aq aq aq aq aq

barium aq aq s aq s aq aq aq s s dcalcium aq aq s aq aq ss aq aq s s d

copper (II) aq aq s aq s s n aq s aq siron (II) aq aq s aq n s s aq s aq siron (III) aq aq n aq s s n aq s s d

lead aq s s ss s s s aq s s smagnesium aq aq s aq aq s aq aq s aq dmercury (I) s s s s s n s aq s s simercury (II) aq s s aq s s s aq s d sipotassium aq aq aq aq aq aq aq aq aq aq aq

silver s s s s s n s s s s ssodium aq aq aq aq aq aq aq aq aq aq aq

zinc aq aq s aq aq s aq aq s aq s

acet

ate

brom

ide

carb

onat

e

chlo

ride

chro

mat

e

hydr

oxid

e

iodi

de

nitra

te

phos

phat

e

sulfa

te

sulfi

de

Legends = solidaq = aqueousd = decomposesn = not isolated

Solubility Rules

1. Most nitrates are soluble.

2. Most salts containing Group I ion and ammonium ion, NH4+, are soluble.

3. Most chloride, bromide, and iodide salts are soluble, except Ag+, Pb2+ and Hg2

2+.

Ohn-Sabatello, Morlan, Knoespel, Fast Track to a 5 Preparing for the AP Chemistry Examination 2006, page 91

4. Most sulfate salts are soluble, except BaSO4, PbSO4, Hg2SO4, and CaSO4.

5. Most hydroxides except Group 1 and Ba(OH)2, Sr(OH)2, and Ca(OH)2 are only slightly soluble.

6. Most sulfides, carbonates, chromates, and phosphates are only slightly soluble.

Find the precipitate1. HCl(aq) + AgNO3(aq) HNO3( ) + AgCl( )2. 3 CaCl2(aq) + 2 Na3PO4(aq) Ca3(PO4)2( ) + 6 NaCl( )3. Pb(NO3)2(aq ) + BaCl2( aq ) PbCl2( ) + Ba(NO3)2( )

4. FeCl3(aq) + 3 NaOH(aq) Fe(OH)3( ) + 3 NaCl( )5. H2SO4(aq) + Ca(OH)2(aq) 2 H2O( ) + CaSO4( )

6. 2 KOH(aq) + CuSO4(aq) K2SO4( ) + Cu(OH)2( )

Predict if these reactions will occur

HCl(aq) + Pb(NO3)2(aq)

Will a precipitate form?

HNO3( ) ?aq + PbCl2( )?SYes, so the reaction will take place.

Don’t forget to balance the equation

22

NH4OH(aq) + CaSO4(aq)

Will a precipitate form?

(NH4)2SO4( ) ?aq + Ca(OH)2( )?aq

No, so the reaction will not take place.

No reaction