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Advanced Reaction Advanced Reaction Topics Topics

Advanced Reaction Topics

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Advanced Reaction Topics. Advanced Reaction Topics. Reaction Rates Equilibrium Acids and Bases Redox Chemistry. Reaction Rates. Reaction Rates. Things that affect the rate of a reaction Temperature Increasing the temperature 10 °C doubles the reaction rate typically Concentration - PowerPoint PPT Presentation

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Page 1: Advanced Reaction Topics

Advanced Reaction TopicsAdvanced Reaction Topics

Page 2: Advanced Reaction Topics

Advanced Reaction TopicsAdvanced Reaction Topics

Reaction RatesReaction RatesEquilibriumEquilibriumAcids and BasesAcids and BasesRedox ChemistryRedox Chemistry

Page 3: Advanced Reaction Topics

Reaction RatesReaction Rates

Page 4: Advanced Reaction Topics

Reaction RatesReaction Rates

Things that affect the rate of a reactionThings that affect the rate of a reactionTemperatureTemperature

Increasing the temperature 10Increasing the temperature 10°C doubles the °C doubles the reaction rate typicallyreaction rate typically

ConcentrationConcentrationSurface AreaSurface AreaCatalystCatalyst

Every reaction is different and has a Every reaction is different and has a different reaction rate.different reaction rate.

Page 5: Advanced Reaction Topics

Collision TheoryCollision Theory Reactions happen when molecules collide with Reactions happen when molecules collide with

each othereach other The reaction only happens IF:The reaction only happens IF:

They collide with enough energyThey collide with enough energy They collide with the right orientation.They collide with the right orientation.

Page 6: Advanced Reaction Topics

How Do They Relate?How Do They Relate?

Things that affect the rate of a reactionThings that affect the rate of a reactionTemperatureTemperature

Increasing Temperature increases the energy in a Increasing Temperature increases the energy in a collision.collision.

ConcentrationConcentrationIncreases the number of particles in the same Increases the number of particles in the same

volume and therefore the number of collisionsvolume and therefore the number of collisions

Surface AreaSurface AreaIncreases the accessible area for collisionsIncreases the accessible area for collisions

Page 7: Advanced Reaction Topics

EquilibriumEquilibrium

Page 8: Advanced Reaction Topics

Fishbowl DemoFishbowl Demo

What are the characteristics once it What are the characteristics once it reaches equilibrium?reaches equilibrium?The amount of “reactants” and “products” is The amount of “reactants” and “products” is

not changingnot changing ““Reactions” are still occurring in both the Reactions” are still occurring in both the

forward and reverse direction.forward and reverse direction.The rate of the “reactions” is the same at The rate of the “reactions” is the same at

equilibriumequilibrium

Page 9: Advanced Reaction Topics

Characteristics of EquilibriumCharacteristics of Equilibrium The amounts of the reactants and products do The amounts of the reactants and products do

not change while the system is at equilibrium.not change while the system is at equilibrium.

Consider: NConsider: N22 + 3H + 3H22 ⇌⇌ 2NH 2NH33

Notice the double half arrows

Page 10: Advanced Reaction Topics

Characteristics of EquilibriumCharacteristics of Equilibrium The forward and reverse reactions still both occur but at The forward and reverse reactions still both occur but at

the same rate.the same rate. For this reason, equilibrium can also be called For this reason, equilibrium can also be called dynamicdynamic

equilibriumequilibrium

Page 11: Advanced Reaction Topics

Acids and BasesAcids and Bases

Page 12: Advanced Reaction Topics

Hydrochloric AcidHydrochloric Acid

HCl(aq)HCl(aq)

What type of compound is it?What type of compound is it?

What type of electrolyte is hydrochloric What type of electrolyte is hydrochloric acid?acid?

Page 13: Advanced Reaction Topics

Hydrochloric AcidHydrochloric Acid

Why does it light up?Why does it light up?

What must be present in solution?What must be present in solution?

Is hydrochloric acid an ionic compound?Is hydrochloric acid an ionic compound?No. It is in a small subset of covalent No. It is in a small subset of covalent

compounds.compounds.

Page 14: Advanced Reaction Topics

Hydrochloric AcidHydrochloric Acid

It must be making It must be making some ions in solutionsome ions in solution

What are the ions?What are the ions?

HCl + HHCl + H22OO H H33OO++

(aq) + Cl(aq) + Cl--(aq)(aq)

Page 15: Advanced Reaction Topics

Hydrochloric AcidHydrochloric Acid

HH33OO++ is called the is called the

hydronium ionhydronium ion

Things that make Things that make hydronium ions in hydronium ions in water are called water are called acids.acids.

Page 16: Advanced Reaction Topics

A Word About HydroniumA Word About Hydronium

Depending on how you look at it acids Depending on how you look at it acids makemakeHH++ - hydrogen ion - hydrogen ionHH33OO++ - hydronium ion - hydronium ion

The two are interchangableThe two are interchangableHH+ + + H+ H22O O H H33OO++

Anytime you see one it can mean the Anytime you see one it can mean the other.other.

Page 17: Advanced Reaction Topics

Common AcidsCommon Acids

Hydrochloric acid Hydrochloric acid (HCl)(HCl) Muriatic acidMuriatic acid

Sulfuric acid (HSulfuric acid (H22SOSO44)) Battery acidBattery acid

Nitric acid (HNONitric acid (HNO33)) Acetic acid (HCAcetic acid (HC22HH33OO22))

VinegarVinegar Phosphoric acid Phosphoric acid

(H(H33POPO44))

Citric Acid Citric Acid Lactic AcidLactic Acid Ascorbic AcidAscorbic Acid

Vitamin CVitamin C Acetylsalicylic AcidAcetylsalicylic Acid

AspirinAspirin Stearic AcidStearic Acid

Page 18: Advanced Reaction Topics

Common BasesCommon Bases

Sodium hydroxideSodium hydroxide Lye, Caustic SodaLye, Caustic Soda

Calcium hydroxideCalcium hydroxide LimeLime

Magnesium hydroxideMagnesium hydroxide Milk of magnesiaMilk of magnesia

AmmoniaAmmonia Sodium hypochloriteSodium hypochlorite

BleachBleach

Sodium hydrogen Sodium hydrogen carbonatecarbonate Baking SodaBaking Soda

Calcium carbonateCalcium carbonate ChalkChalk TumsTums

Page 19: Advanced Reaction Topics

Acids and BasesAcids and BasesArrhenius DefinitionsArrhenius Definitions

Arrhenius AcidArrhenius Acid – a substance that dissociates – a substance that dissociates and produces hydronium ions in waterand produces hydronium ions in water

Arrhenius BaseArrhenius Base – a substance that dissociates – a substance that dissociates and produces hydroxide ions in waterand produces hydroxide ions in water

BrBrønsted-Lowry Definitionsønsted-Lowry DefinitionsBrBrønsted-Lowry Acidønsted-Lowry Acid – a substance that – a substance that

donates a hydrogen ion (Hdonates a hydrogen ion (H++) (a proton)) (a proton)BrBrønsted-Lowry Baseønsted-Lowry Base – a substance that – a substance that

accepts a hydrogen ion (Haccepts a hydrogen ion (H++) (a proton)) (a proton)

Page 20: Advanced Reaction Topics

Acid and Base DefinitionsAcid and Base Definitions

There is quite a bit of overlap between the There is quite a bit of overlap between the definitionsdefinitions

HCl + HHCl + H22O O Cl Cl-- + H + H33OO++

HCl dissociates and produces hydronium ionsHCl dissociates and produces hydronium ionsArrhenius AcidArrhenius Acid

HCl donates an HHCl donates an H++ to water to waterBrønsted-Lowry AcidBrønsted-Lowry Acid

All Arrhenius Acids are Brønsted-Lowry Acids All Arrhenius Acids are Brønsted-Lowry Acids and vice versa.and vice versa.

Page 21: Advanced Reaction Topics

Acid and Base DefinitionsAcid and Base Definitions Relations between the base definitions are not Relations between the base definitions are not

as simple.as simple. NaOH dissolves in water to form NaNaOH dissolves in water to form Na++ and OH and OH--

Arrhenius BaseArrhenius Base NaOH + HNaOH + H++ Na Na++ + H + H22OO

BrBrønsted-Lowry Baseønsted-Lowry Base Hydroxides are both Arrhenius and Brønsted-Lowry Hydroxides are both Arrhenius and Brønsted-Lowry

Bases.Bases. Non-hydroxide bases can’t be Arrhenius basesNon-hydroxide bases can’t be Arrhenius bases

No hydroxide obviously…No hydroxide obviously… Non-hydroxide bases will be Brønsted-Lowry Non-hydroxide bases will be Brønsted-Lowry

basesbases COCO33

2-2- + H + H+ + HCO HCO33--

NHNH33 + H + H++ NH NH44++

Page 22: Advanced Reaction Topics

Acid and Base DefinitionsAcid and Base Definitions

Arrhenius acids and bases are tied to Arrhenius acids and bases are tied to waterwater

BrBrønsted-Lowry acids and bases are not.ønsted-Lowry acids and bases are not.BrBrønsted-Lowry can be used to describe ønsted-Lowry can be used to describe

reactions in the gas phase or in other solvents reactions in the gas phase or in other solvents besides water.besides water.

Page 23: Advanced Reaction Topics

Acid-Base DefinitionsAcid-Base Definitions Monoprotic acidMonoprotic acid – an acid that has one ionizable – an acid that has one ionizable

hydrogenhydrogen HCl, HNOHCl, HNO33

Diprotic acidDiprotic acid – an acid that has two ionizable – an acid that has two ionizable hydrogenshydrogens HH22SOSO44

Triprotic acidTriprotic acid – an acid that has three ionizable – an acid that has three ionizable hydrogenshydrogens HH33POPO44

What kind of acid is acetic acid, HCWhat kind of acid is acetic acid, HC22HH33OO22?? MonoproticMonoprotic Typically only hydrogens written first are ionizable.Typically only hydrogens written first are ionizable.

Page 24: Advanced Reaction Topics
Page 25: Advanced Reaction Topics

Autolysis of WaterAutolysis of Water

Water spontaneously splits itselfWater spontaneously splits itself2H2H22O O ⇌⇌ H H33OO++ + OH + OH––

An equilibrium system.An equilibrium system.Makes equal parts hydronium and Makes equal parts hydronium and

hydroxidehydroxideEqual parts acid and baseEqual parts acid and base

Water is neutral.Water is neutral.

Page 26: Advanced Reaction Topics

Autolysis of WaterAutolysis of Water

We will use brackets to represent molarityWe will use brackets to represent molarity

[H[H33OO++] is the molarity of the hydronium ion.] is the molarity of the hydronium ion.

When acids and bases are dissolved in When acids and bases are dissolved in water [Hwater [H33OO++][OH][OH––] = K] = Kww = 1x10 = 1x10-14-14

Page 27: Advanced Reaction Topics

Acid Base ReactionsAcid Base Reactions

Acid Base Neutralization ReactionAcid Base Neutralization ReactionHA + B HA + B A + HB A + HBTransfer of hydrogen ions (HTransfer of hydrogen ions (H++))

Hydrochloric acid and sodium hydroxide Hydrochloric acid and sodium hydroxide solutions are mixedsolutions are mixed

Page 28: Advanced Reaction Topics

Acid Base ReactionsAcid Base Reactions

Acid Base Neutralization ReactionAcid Base Neutralization ReactionHA + B HA + B A + HB A + HBTransfer of hydrogen ions (HTransfer of hydrogen ions (H++))

Acetic acid and barium hydroxide solutions Acetic acid and barium hydroxide solutions are mixed.are mixed.

Page 29: Advanced Reaction Topics

Acid Base ReactionsAcid Base Reactions

Acid Base Neutralization ReactionAcid Base Neutralization ReactionHA + B HA + B A + HB A + HBTransfer of hydrogen ions (HTransfer of hydrogen ions (H++))

Ammonia and sulfuric acid solutions are Ammonia and sulfuric acid solutions are mixedmixed

Page 30: Advanced Reaction Topics

Acid Base ReactionsAcid Base Reactions

Acid Base Neutralization ReactionAcid Base Neutralization ReactionHA + B HA + B A + HB A + HBTransfer of hydrogen ions (HTransfer of hydrogen ions (H++))

Hydrochloric acid and sodium sulfide Hydrochloric acid and sodium sulfide solutions are mixed.solutions are mixed.

Page 31: Advanced Reaction Topics

AcidsAcids

Hydrochloric acidHydrochloric acid Is it an electrolyte?Is it an electrolyte?Why is it an electrolyte?Why is it an electrolyte?

Acetic acidAcetic acid Is it an electrolyte?Is it an electrolyte?Why is it an electrolyte?Why is it an electrolyte?Why doesn’t it light up as much as Why doesn’t it light up as much as

hydrochloric acid?hydrochloric acid?

Page 32: Advanced Reaction Topics

Strength of Acids and BasesStrength of Acids and Bases

Hydrochloric acid completely dissociatesHydrochloric acid completely dissociatesHCl + HHCl + H22O O H H33OO++ + Cl + Cl--

Acetic acid doesn’t make as many ionsAcetic acid doesn’t make as many ionsAcetic acid partially dissociatesAcetic acid partially dissociatesHCHC22HH33OO22 + H + H22O O ⇌⇌ H H33OO++ + C + C22HH33OO22

––

Around 0.5% of acetic acid molecules make Around 0.5% of acetic acid molecules make hydronium ionshydronium ions

Reactant side is very favored.Reactant side is very favored.

Page 33: Advanced Reaction Topics

Strength of Acids and BasesStrength of Acids and Bases Strong acid or baseStrong acid or base – an acid or base that – an acid or base that

completely reacts with water to form hydronium completely reacts with water to form hydronium ions or hydroxide ions.ions or hydroxide ions. Strong acids – hydrochloric, sulfuric, nitricStrong acids – hydrochloric, sulfuric, nitric Strong bases – LiOH, NaOH, KOH, RbOH, CsOH, Strong bases – LiOH, NaOH, KOH, RbOH, CsOH,

Ca(OH)Ca(OH)22, Sr(OH), Sr(OH)22, Ba(OH), Ba(OH)22

Weak acid or baseWeak acid or base – an acid or base that – an acid or base that partially reacts with water to form hydronium partially reacts with water to form hydronium ions or hydroxide ions.ions or hydroxide ions. Weak acids – everything except the aboveWeak acids – everything except the above Weak bases – everything except the aboveWeak bases – everything except the above

Page 34: Advanced Reaction Topics

Strong Acid

Weak Acid

Page 35: Advanced Reaction Topics

Strength of Acids and BasesStrength of Acids and BasesStrength does not describe concentrationStrength does not describe concentration

ConsiderConsiderA bottle of “glacial” acetic acid (99%)A bottle of “glacial” acetic acid (99%)A bottle of concentrated sulfuric acid (98%)A bottle of concentrated sulfuric acid (98%)

Both have (nearly) the same concentrationBoth have (nearly) the same concentrationAcetic acid will not ionize as much in water Acetic acid will not ionize as much in water

as sulfuric acid willas sulfuric acid willAcetic acid is a “weak” acidAcetic acid is a “weak” acid

Page 36: Advanced Reaction Topics
Page 37: Advanced Reaction Topics

Concentration of AcidsConcentration of Acids

If not all acids completely dissociate in If not all acids completely dissociate in waterwaterThe concentration of the acid molecules is The concentration of the acid molecules is

different for every aciddifferent for every acidThe concentration of the hydronium ion in The concentration of the hydronium ion in

different acids is differentdifferent acids is different

Need a system that describes the Need a system that describes the concentration of acids.concentration of acids.

Page 38: Advanced Reaction Topics

pHpHpH = -log [HpH = -log [H33OO++]]

Also define a relationship for the amount Also define a relationship for the amount of baseof base

pOH = -log [OHpOH = -log [OH––]]

How do you reverse a log?How do you reverse a log?1010-pH-pH = [H = [H33OO++]]1010-pOH-pOH = [OH = [OH––]]

Page 39: Advanced Reaction Topics

How are pH and pOH related?How are pH and pOH related?

KKww = [H = [H33OO++][OH][OH––]]

log Klog Kww = log ([H = log ([H33OO++][OH][OH––])])

log Klog Kww = log [H = log [H33OO++] + log [OH] + log [OH––]]

log 1x10log 1x10-14-14 = log [H = log [H33OO++] + log [OH] + log [OH––]]

-14 = log [H-14 = log [H33OO++] + log [OH] + log [OH––]]

14 = -log [H14 = -log [H33OO++] + -log [OH] + -log [OH––]]

14 = pH + pOH14 = pH + pOH

Page 40: Advanced Reaction Topics

pH ScalepH Scale

Take 7 minutes to fill in this pH scale using Take 7 minutes to fill in this pH scale using the chemical formulas you know.the chemical formulas you know.

Page 41: Advanced Reaction Topics
Page 42: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the pH of a solution with [HWhat is the pH of a solution with [H++] of ] of 1.0x101.0x10-3-3 M? M?

Page 43: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the pOH of a solution with [HWhat is the pOH of a solution with [H++] of ] of 1.0x101.0x10-3-3 M? M?

Page 44: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the [OHWhat is the [OH--] of a solution with a pH of ] of a solution with a pH of 9.00?9.00?

Page 45: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the [OHWhat is the [OH--] of a solution with an ] of a solution with an [H[H33OO++] concentration of 1.0x10] concentration of 1.0x10-5-5 M? M?

Page 46: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the pH of a solution with a What is the pH of a solution with a hydronium ion concentration of hydronium ion concentration of 2.55x102.55x10-4-4M?M?

Page 47: Advanced Reaction Topics

Practice ProblemsPractice Problems

What is the pOH of a solution that has a What is the pOH of a solution that has a hydronium ion concentration of hydronium ion concentration of 5.50x105.50x10-8 -8 M?M?

Page 48: Advanced Reaction Topics

IndicatorsIndicators Colored compounds that are sensitive to Colored compounds that are sensitive to

changes in pHchanges in pH Indicators will change color based on how acidic Indicators will change color based on how acidic

or basic the conditions around it areor basic the conditions around it are Chemical reaction with the acids or basesChemical reaction with the acids or bases

OH OH

O

O

O O-

O

O-

Acidic Conditions (pH<8.2) Basic Conditions (pH>10.0)

Phenolphthalein

Page 49: Advanced Reaction Topics
Page 50: Advanced Reaction Topics

Universal IndicatorUniversal Indicator Universal Indicator is a mixture of different Universal Indicator is a mixture of different

indicators.indicators.

Resulting color depends on each of the four Resulting color depends on each of the four indicator’s statesindicator’s states

Page 51: Advanced Reaction Topics
Page 52: Advanced Reaction Topics

Redox ChemistryRedox Chemistry

Page 53: Advanced Reaction Topics

ElectrolysisElectrolysis

Run a current through Run a current through water.water.

Splits water into Splits water into hydrogen and oxygenhydrogen and oxygen

2H2H22O O 2H 2H22 + O + O22

Page 54: Advanced Reaction Topics

Oxidation NumbersOxidation Numbers

Describes the relative amount of electrons Describes the relative amount of electrons associated with a particular atomassociated with a particular atom

Has no actual physical meaning (for the Has no actual physical meaning (for the most part)most part)

Only an electron bookkeeping method.Only an electron bookkeeping method.

Page 55: Advanced Reaction Topics

Oxidation NumbersOxidation Numbers1.1. Every uncombined element in its natural state has Every uncombined element in its natural state has

an oxidation number of zero.an oxidation number of zero.2.2. The oxidation number of a monatomic ion is its The oxidation number of a monatomic ion is its

charge.charge.3.3. Remember the following:Remember the following:

Fluorine in a compound is always -1Fluorine in a compound is always -1 Hydrogen is a +1 normally in a compound. It is -1 Hydrogen is a +1 normally in a compound. It is -1

when a hydride.when a hydride. Oxygen is almost always -2 in a compound unless it is Oxygen is almost always -2 in a compound unless it is

a peroxide (-1)a peroxide (-1)

4.4. The sum of the individual oxidation numbers on The sum of the individual oxidation numbers on every atom in a species is equal to the overall every atom in a species is equal to the overall charge on that species.charge on that species.

Page 56: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

CHFCHF33

Page 57: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

BaClBaCl22

Page 58: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

KNOKNO33

Page 59: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

SS22OO332-2-

Page 60: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

PP44

Page 61: Advanced Reaction Topics

Oxidation Numbers PracticeOxidation Numbers Practice

Give the oxidation number of every element Give the oxidation number of every element in the following compounds.in the following compounds.

(NH(NH44))22CC22OO44

Page 62: Advanced Reaction Topics

Oxidation and ReductionOxidation and Reduction

Oxidation Oxidation - chemical - chemical process involving the process involving the loss of electrons.loss of electrons.

ReductionReduction – chemical – chemical process involving process involving gaining electrons.gaining electrons.

LEO the lion goes LEO the lion goes GERGER

OIL RIGOIL RIG

Page 63: Advanced Reaction Topics

Oxidation and ReductionOxidation and Reduction Consider: Consider:

MnOMnO44-- + C + C22OO44

2-2- + H + H++ Mn Mn2+2+ + CO + CO22 + H + H22OO

What element has been reduced?What element has been reduced? What element has been oxidized?What element has been oxidized? What species reacted with the element that was What species reacted with the element that was

reduced?reduced? This is the This is the reducing agentreducing agent..

What species reacted with the element that was What species reacted with the element that was oxidized?oxidized? This is the This is the oxidizing agentoxidizing agent..

Page 64: Advanced Reaction Topics
Page 65: Advanced Reaction Topics

Vanadium Oxidation StatesVanadium Oxidation States

Vanadium oxidation states.mov

Page 66: Advanced Reaction Topics

PracticePractice Identify the element oxidized, the element Identify the element oxidized, the element

reduced, the species that is the oxidizing reduced, the species that is the oxidizing agent, and the species that is the reducing agent, and the species that is the reducing agent in:agent in:

II-- + ClO + ClO-- + H + H++ I I33-- + Cl + Cl-- + H + H22OO

Page 67: Advanced Reaction Topics

PracticePractice Identify the element oxidized, the element Identify the element oxidized, the element

reduced, the species that is the oxidizing reduced, the species that is the oxidizing agent, and the species that is the reducing agent, and the species that is the reducing agent in:agent in:

HH++ + Cr + Cr22OO772-2- + C + C22HH55OH OH Cr Cr3+3+ + CO + CO22 + H + H22OO

Page 68: Advanced Reaction Topics

Half ReactionHalf Reaction

Different Parts of redox reactions are Different Parts of redox reactions are interchangableinterchangable

We split redox reactions into two partsWe split redox reactions into two parts Oxidation half reactionOxidation half reaction Reduction half reactionReduction half reaction

Write the compounds or ions involved and show Write the compounds or ions involved and show which ones are losing and gaining electronswhich ones are losing and gaining electrons

Page 69: Advanced Reaction Topics

Practice ProblemsPractice Problems

Cu + AgCu + Ag++ Cu Cu2+2+ + Ag + Ag

Page 70: Advanced Reaction Topics

Practice ProblemsPractice Problems

Al + HAl + H++ Al Al3+3+ + H + H22

Page 71: Advanced Reaction Topics

Practice ProblemsPractice Problems

FF22 + Cl + Cl-- F F-- + Cl + Cl22

Page 72: Advanced Reaction Topics

Practice ProblemsPractice Problems

SnSn2+2+ + Fe + Fe3+3+ Fe Fe2+2+ + Sn + Sn4+4+

Page 73: Advanced Reaction Topics

Balancing Redox ReactionsBalancing Redox Reactions

This gets ugly.This gets ugly.

Must follow the process.Must follow the process.

Page 74: Advanced Reaction Topics

The Rules – Copy the RestThe Rules – Copy the Rest

1.1. Split the overall reaction into two half Split the overall reaction into two half reactions, one for oxidation and one for reactions, one for oxidation and one for reduction.reduction.

2.2. Balance each half reaction separatelyBalance each half reaction separatelya)a) Balance everything but O and HBalance everything but O and H

b)b) Balance O by adding HBalance O by adding H22O where necessaryO where necessary

c)c) Balance H by adding HBalance H by adding H++ where necessary where necessary

d)d) Balance the charge by adding electrons.Balance the charge by adding electrons.

Page 75: Advanced Reaction Topics

The Rules – Copy the RestThe Rules – Copy the Rest3.3. Make the number of electrons in the two Make the number of electrons in the two

half reactions agree by multiplying the half reactions agree by multiplying the entire half reaction by coefficients.entire half reaction by coefficients.

4.4. Add the two half reactions and cancel Add the two half reactions and cancel identical speciesidentical species

5.5. Double check to make sure everything Double check to make sure everything (elements and charge) is (elements and charge) is balanced!!!!!!!!balanced!!!!!!!!

These rules apply to reactions occurring These rules apply to reactions occurring under acidic conditions – that’s all we under acidic conditions – that’s all we need for this classneed for this class

Page 76: Advanced Reaction Topics

Practice ProblemsPractice Problems Dichromate and iodide ions react in acidic Dichromate and iodide ions react in acidic

solution to form chromium(III) and iodate ions.solution to form chromium(III) and iodate ions.

Page 77: Advanced Reaction Topics

Practice ProblemsPractice Problems Permanganate ions and methanol (CHPermanganate ions and methanol (CH33OH) OH)

react to form manganese(II) ions and formic acid react to form manganese(II) ions and formic acid (HCO(HCO22H) in acidic solution.H) in acidic solution.

Page 78: Advanced Reaction Topics

Practice ProblemsPractice Problems Arsenic metal and chlorate ions react in acidic Arsenic metal and chlorate ions react in acidic

solution to form arsenous acid (Hsolution to form arsenous acid (H33AsOAsO33) and ) and hypochlorous acid (HClO)hypochlorous acid (HClO)

Page 79: Advanced Reaction Topics

Practice ProblemsPractice Problems Solid iodine reacts with hypochlorite ions to form Solid iodine reacts with hypochlorite ions to form

iodate ions and chloride ions in acidic iodate ions and chloride ions in acidic conditions.conditions.

Page 80: Advanced Reaction Topics

Practice ProblemsPractice Problems Arsenic metal and chlorate ions react in acidic solution to Arsenic metal and chlorate ions react in acidic solution to

form arsenous acid (Hform arsenous acid (H33AsOAsO33) and hypochlorous acid ) and hypochlorous acid (HClO)(HClO)

Solid iodine reacts with hypochlorite ions to form iodate Solid iodine reacts with hypochlorite ions to form iodate ions and chloride ions in acidic conditions.ions and chloride ions in acidic conditions.

Oxalate ions (COxalate ions (C22OO442-2-) and permanganate ions react in ) and permanganate ions react in

acidic conditions to form manganese(II) ions and carbon acidic conditions to form manganese(II) ions and carbon dioxide.dioxide.

Dichromate ions react with hydrogen peroxide to Dichromate ions react with hydrogen peroxide to produce chromium(III) ions and oxygen gas in acidic produce chromium(III) ions and oxygen gas in acidic conditionsconditions

Aluminum metal reacts with iodate ions in acidic solution Aluminum metal reacts with iodate ions in acidic solution to form aluminum ions and solid iodine.to form aluminum ions and solid iodine.

Page 81: Advanced Reaction Topics

Uses of Redox ChemistryUses of Redox Chemistry

BatteriesBatteries Harnessed flow of Harnessed flow of

electrons driven by electrons driven by redox reaction.redox reaction.

Car batteryCar battery

PbOPbO22(s) + Pb(s) + 2H(s) + Pb(s) + 2H22SOSO44 2PbSO 2PbSO44(s) + 2H(s) + 2H22OO

Page 82: Advanced Reaction Topics

Alkaline BatteriesAlkaline Batteries

Zn + 2MnOZn + 2MnO22 ZnO + Mn ZnO + Mn22OO33

Page 83: Advanced Reaction Topics

Fuel CellsFuel Cells

2H2H22 + O + O22 2H 2H22OO

Page 84: Advanced Reaction Topics

ElectroplatingElectroplating

Page 85: Advanced Reaction Topics

CorrosionCorrosion