Double Displacement ReactionsDouble Displacement Reactions

Non-Redox ReactionsNon-Redox Reactions

Reactants: Zn + IReactants: Zn + I22 Product: Zn IProduct: Zn I22

Things my Mother taught me…

RELIGION.      "You better pray that will come out of the carpet."

Double Displacement Reactions:Double Displacement Reactions:At the conclusion of our time together, At the conclusion of our time together,

you should be able to:you should be able to:

Distinguish between a non-redox and a redox reaction.Recognize a double replacement (D.R.) reaction.Predict the products of a D.R. reaction.Predict whether a D.R. reaction will occur using solubility rules or formation of gas or H2O(l) (neutralization reaction).

Non-Redox ReactionNon-Redox Reaction

The oxidation number (charge) of the ions The oxidation number (charge) of the ions involved does not change from the reactant involved does not change from the reactant to the product side.to the product side.

NaNa22SOSO4(aq)4(aq) + + CaClCaCl2(aq)2(aq) CaCaSOSO4(s)4(s) + 2Na + 2NaClCl(aq)(aq)

Redox: (the oxidation #’s are changing)Redox: (the oxidation #’s are changing)

2 Fe + 3 Cl2 Fe + 3 Cl22 2 FeCl 2 FeCl33

2 K2 K(s)(s) + FeCl+ FeCl2(aq) 2(aq) Fe Fe(s)(s) + 2 KCl+ 2 KCl(aq)(aq)

Double Replacement ReactionsDouble Replacement Reactions

Two things replace each other.Two things replace each other. Reactants must be two ionic compounds or Reactants must be two ionic compounds or

acids.acids. Usually in aqueous solutionUsually in aqueous solution NaNa22SOSO4(aq)4(aq) + + CaClCaCl2(aq)2(aq) The positive ions change place.The positive ions change place. NaNa22SOSO4(aq)4(aq)+ + CaClCaCl2(aq)2(aq)CaCa+2+2 SOSO44

2-2- + Na + Na+1+1ClCl-1-1

NaNa22SOSO4(aq)4(aq) + + CaClCaCl2(aq)2(aq) CaCaSOSO4(s)4(s) + 2Na + 2NaClCl(aq)(aq)

“Disorder in the American Courts”

These are statements people actually said in court, word for word, taken down and now published by court

reporters.ATTORNEY:  The youngest son, the 20-year-old, how old is he?WITNESS:     He's 20, much like your IQ.

To Double ReplaceTo Double Replaceor or

Not to Double Replace?Not to Double Replace?That is the Question?That is the Question?

Will only happen if one of the productsWill only happen if one of the products doesn’t dissolve in water and forms an doesn’t dissolve in water and forms an

insoluble solid (s), precipitate (ppt or ).insoluble solid (s), precipitate (ppt or ). or is a gas that bubbles out.or is a gas that bubbles out. or water forms, Hor water forms, H22O (neutralization O (neutralization

reaction).reaction).

Predicting the PrecipitatePredicting the Precipitate

Insoluble salt = a precipitateInsoluble salt = a precipitate Solubility rulesSolubility rules (see handout for explanation)(see handout for explanation)

CASH N GiAmCASH N GiAm

Solubility Rules PracticeSolubility Rules PracticePredict whether each of the following will be Predict whether each of the following will be

soluble (aq) or an insoluble ppt. (s):soluble (aq) or an insoluble ppt. (s):

KClKCl

NaNa22SOSO44

CaSOCaSO44

AgSOAgSO44

NaNa22COCO33

MgSMgS

aqaq aqaq ss ss aqaq ss

Double Replacement ReactionsDouble Replacement Reactions

• Double Replacement Reactions Double Replacement Reactions occur when occur when a metal replaces a metal in a compound and a a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compoundnonmetal replaces a nonmetal in a compound

• Compound + compound Compound + compound compound+ compound+ compoundcompound

• AB + CD AB + CD AD + CB AD + CB

Another Redneck Innovation:Another Redneck Innovation:

Double Replacement ReactionsDouble Replacement Reactions

• Think about it like “foil”ing in algebra, first and Think about it like “foil”ing in algebra, first and last ions go together + inside ions go togetherlast ions go together + inside ions go together

• Example:Example:

AgNOAgNO3(aq) 3(aq) + NaCl+ NaCl(s) (s) AgCl AgCl(s) (s) + NaNO+ NaNO3(aq)3(aq)

• Another example:Another example:

KK22SOSO4(aq) 4(aq) + Ba(NO+ Ba(NO33))2(aq) 2(aq) KNO KNO3(aq)3(aq) + BaSO + BaSO4(s) 4(s) 2

Double Displacement Reactions:Double Displacement Reactions:Let’s see if you can:Let’s see if you can:

Distinguish between a non-redox and a redox reaction.Recognize a double replacement (D.R.) reaction.Predict the products of a D.R. reaction.Predict whether a D.R. reaction will occur using solubility rules or formation of gas or H2O(l) (neutralization reaction).

3 Driving Forces for Double Replacement 3 Driving Forces for Double Replacement ReactionsReactions

• Water Forms• Gas Forms• Solid Forms• If one of the above is not a

product, there will be no reaction.

Double ReplacementDouble Replacement

Two elements in reactants take the place of each other

AB + CD AD + CB

AgNO3(aq)+ NaCl(aq)

AgCl(s) + NaNO3(aq)

Zn(OH)2(aq) + 2HCl(aq)

ZnCl2(aq) + 2H2O(l)

You Might Be a Redneck If…

The Salvation Army declines your mattress.

You have the local taxidermist on speed dial.

PracticePractice

• Predict the products. Balance the equationPredict the products. Balance the equation

1.1. HClHCl(aq)(aq) + AgNO + AgNO33(aq) (aq)

2.2. CaClCaCl22(aq) (aq) + Na+ Na33POPO4 (aq) 4 (aq)

3.3. Pb(NOPb(NO33)) 2(aq) 2(aq) + BaCl+ BaCl2 (aq) 2 (aq)

4.4. FeClFeCl3 (aq) 3 (aq) + NaOH+ NaOH(aq) (aq)

5.5. HH22SOSO44(aq)(aq) + NaOH + NaOH(aq)(aq)

6.6. KOHKOH(aq)(aq) + CuSO + CuSO4 (aq) 4 (aq)

7.7. Ba(NOBa(NO33)) 2(aq) 2(aq) + K+ K22CrOCrO4 (aq) 4 (aq)

8.8. Demo Time!! Demo Time!!

AgCl + HNO3

NaCl + Ca3 (PO4) 2

Ba(NO3) 2 + PbCl2NaCl + Fe(OH) 3

Na2SO4 + H2O

Cu(OH) 2 + K2SO4

BaCrO4 + KNO3

Learning CheckLearning Check

Which of the following reactions is double replacement?

A. 2Al(s) + 3H2SO4(aq) Al2(SO4)3(aq) + 3H2(g)

B. Na2SO4(aq) + 2AgNO3(aq)Ag2SO4(s)+

2NaNO3(aq)

C. 3C(s) + Fe2O3(s) 2Fe(g) + 3CO(g)

Complete and Net Ionic EquationsComplete and Net Ionic Equations

Complete and Net Ionic EquationsComplete and Net Ionic Equations

Reactants: Zn + IReactants: Zn + I22 Product: Zn IProduct: Zn I22

Murphy's LawsMurphy's Lawsofof

Science and TechnologyScience and Technology

Any instrument when dropped will roll into the least accessible corner.

Complete and Net Ionic Complete and Net Ionic Equations:Equations:

At the conclusion of our time together, At the conclusion of our time together, you should be able to:you should be able to:

1.1. Define molecular, complete and net ionic Define molecular, complete and net ionic equationsequations

2.2. Write molecular, complete and net ionic Write molecular, complete and net ionic equationsequations

3.3. Identify a neutralization reactionIdentify a neutralization reaction4.4. Realize that this is one of the 5 basic Realize that this is one of the 5 basic

types of chemical reactionstypes of chemical reactions

Complete & Net Ionic EquationsComplete & Net Ionic Equations

Many reactions occur in water- Many reactions occur in water- that is, in that is, in aqueous solutionaqueous solution

Many ionic compounds Many ionic compounds “dissociate”, or separate, into “dissociate”, or separate, into cations and anions when cations and anions when dissolved in waterdissolved in water

Now we can write a Now we can write a complete complete ionic equationionic equation & & net ionic net ionic equation.equation.

Complete Ionic EquationsComplete Ionic Equations

Once you write the molecular equation, Once you write the molecular equation, you should check for reactants and you should check for reactants and products that are soluble or insoluble.products that are soluble or insoluble.

We usually assume the reaction is in waterWe usually assume the reaction is in water We can use a solubility table to tell us We can use a solubility table to tell us

what compounds dissolve in water.what compounds dissolve in water. If the compound is soluble (does dissolve If the compound is soluble (does dissolve

in water), then split the compound into its in water), then split the compound into its component ionscomponent ions

If the compound is insoluble (does NOT If the compound is insoluble (does NOT dissolve in water), then it remains as a dissolve in water), then it remains as a compoundcompound

Solubility TableSolubility Table

Solubilities Not on the Table!Solubilities Not on the Table!

Gases will only slightly dissolve in waterGases will only slightly dissolve in water Strong acids and bases dissolve in waterStrong acids and bases dissolve in water

Hydrochloric, Hydrobromic, Hydroiodic, Hydrochloric, Hydrobromic, Hydroiodic, (All Binaries)(All Binaries) Nitric, Sulfuric, Perchloric AcidsNitric, Sulfuric, Perchloric Acids (Ternary Acids with 2 more O than H)(Ternary Acids with 2 more O than H) Group I hydroxidesGroup I hydroxides

Water slightly dissolves in water! (H+ and Water slightly dissolves in water! (H+ and OH-)OH-)

Another Why - Maxine

Do  Lipton Tea employees take “coffee breaks”?

Complete Ionic EquationComplete Ionic Equation

Example:Example:

AgNOAgNO3(aq)3(aq) + NaCl + NaCl (aq)(aq) AgCl AgCl (s)(s) + NaNO + NaNO3(aq)3(aq)

1.1. This is the This is the full equation (molecular full equation (molecular equation)equation)

2.2. Now write it as an Now write it as an complete complete ionic equationionic equation

Anything (aq) will dissociate (separate into Anything (aq) will dissociate (separate into ions)ions)

AgAg++ + NO + NO33- - + Na+ Na++ + Cl + Cl- - AgCl AgCl(s)(s) + Na + Na++ + NO + NO33

--

Net Ionic EquationNet Ionic Equation

Complete ionic equation:Complete ionic equation:

AgAg++ + NO + NO33- - + Na+ Na++ + Cl + Cl- - AgCl AgCl(s)(s) + Na + Na++ + NO + NO33

--

3. Can be simplified by 3. Can be simplified by eliminating ions eliminating ions not not directly involved in making the reaction directly involved in making the reaction happen happen (spectator ions) (spectator ions) = = net ionic net ionic equationequation

AgAg++ + Cl + Cl-- AgCl AgCl(s)(s)

NaNa++ and NO and NO33-- are are spectator ions spectator ions and are and are

removed in the net ionic equation.removed in the net ionic equation.

Interesting Answers to Catholic Elementary School Bible Questions:

The greatest miracle in the Bible is when Joshua told his son to stand still and he obeyed him!!

Try Again: Complete Ionic Try Again: Complete Ionic EquationsEquations

Molecular Equation:Molecular Equation:

KK22CrOCrO4(aq)4(aq) + Ba(NO + Ba(NO33))2(aq)2(aq) BaCrO BaCrO4(s)4(s) + 2 + 2

KNOKNO3(aq)3(aq)

SolubleSoluble Soluble Insoluble Soluble Soluble Insoluble Soluble

Complete Ionic Equation:Complete Ionic Equation:

2 K2 K++ + CrO + CrO44 -2-2 + Ba+ Ba+2+2 + 2 NO + 2 NO33--

BaCrOBaCrO44 (s) + 2 K (s) + 2 K++ + 2 NO + 2 NO33--

Net Ionic EquationsNet Ionic Equations

These are the same as complete ionic These are the same as complete ionic equations, but you should cancel out ions equations, but you should cancel out ions that appear on BOTH sides of the equationthat appear on BOTH sides of the equation

Complete Ionic Equation:Complete Ionic Equation:

2 K2 K++ + CrO + CrO44 -2-2 + Ba + Ba+2+2 + 2 NO + 2 NO33--

BaCrOBaCrO44 (s) + 2 K (s) + 2 K++ + 2 + 2 NONO33

--

Net Ionic Equation:Net Ionic Equation:

CrOCrO44 -2-2 + Ba + Ba+2+2 BaCrO BaCrO44 (s) (s)Spectator Ion

Neutralization ReactionNeutralization Reaction

Acid + Base Acid + Base Salt + Water Salt + Water

Molecular Equation:Molecular Equation:

HCl + NaOH HCl + NaOH NaCl + HNaCl + H22OO

SolubleSoluble Soluble Soluble MolecularSoluble Soluble Molecular

Complete Ionic Equation:Complete Ionic Equation:

HH++ + Cl + Cl-- + Na + Na++ + OH + OH-- HH22O (O (ll) + Na) + Na++ + Cl + Cl--

Net Ionic Equation for Net Ionic Equation for Neutralization ReactionsNeutralization Reactions

These are the same as complete ionic These are the same as complete ionic equations, but you should cancel out ions equations, but you should cancel out ions that appear on BOTH sides of the equationthat appear on BOTH sides of the equation

Complete Ionic Equation:Complete Ionic Equation:

HH++ + Cl + Cl-- + Na + Na++ + OH + OH-- HH22O (O (ll) + Na) + Na++ + Cl + Cl- -

Net Ionic Equation:Net Ionic Equation:

HH++ + OH + OH-- H H22O (O (ll))

Complete Ionic Equations:Complete Ionic Equations:Let’s see if you can:Let’s see if you can:

1.1. Define molecular, complete and net ionic Define molecular, complete and net ionic equationsequations

2.2. Write molecular, complete and net ionic Write molecular, complete and net ionic equationsequations

3.3. Identify a neutralization reactionIdentify a neutralization reaction4.4. Realize that this is one of the 5 basic Realize that this is one of the 5 basic

types of chemical reactionstypes of chemical reactions

Familiar SayingFamiliar Saying

One pyrus malus per diem restrains the arrival of the Hippocratic apostle.

An apple a day keeps the doctor away!!

Practice Quiz Practice Quiz Net Ionic EquationsNet Ionic Equations

Write the molecular, complete ionic, and net Write the molecular, complete ionic, and net ionic equations for this reaction: Silver nitrate ionic equations for this reaction: Silver nitrate reacts with calcium chloridereacts with calcium chloride

Molecular: Molecular:

2AgNO2AgNO33 + CaCl + CaCl22 2AgCl + Ca(NO 2AgCl + Ca(NO33))22

Complete Ionic:Complete Ionic:

2Ag2Ag++ + 2NO + 2NO33--+ Ca+ Ca2+2+ + 2Cl + 2Cl-- 2AgCl + Ca 2AgCl + Ca2+2+ + +

2NO2NO33--

Net Ionic:Net Ionic:

2Ag2Ag++ + + 2Cl2Cl-- 2AgCl 2AgCl

I don’t feel so stupid now…I don’t feel so stupid now…