1 Ch. 4 Patterns of Chemical Reactivity lDemo: Pour together two clear colorless liquids lDid a...

11

Ch. 4 Patterns of Chemical Ch. 4 Patterns of Chemical ReactivityReactivity

Ch. 4 Patterns of Chemical Ch. 4 Patterns of Chemical ReactivityReactivity

Demo: Pour together two clear colorless Demo: Pour together two clear colorless liquidsliquids

Did a chemical reaction occur?Did a chemical reaction occur?How do you know?How do you know?

Demo: AlkaSeltzer in water, Demo: AlkaSeltzer in water, or calcium in wateror calcium in water

Did a chemical reaction occur?Did a chemical reaction occur?

04m13vd104m13vd1

22

Observing and Predicting Reactions

Observing and Predicting Reactions

How do we know whether a reaction How do we know whether a reaction occurs? What clues does nature offer? occurs? What clues does nature offer? Make a list.Make a list.

Review photos of reactionsReview photos of reactions

Go to next Go to next topictopic

44

Precipitate FormationPrecipitate Formation

AgAg++ + Cl + Cl-- AgCl AgCl Cr Cr3+3+ + 3OH + 3OH-- Cr(OH) Cr(OH)33

BaBa2+2+ + CrO + CrO442-2- BaCrO BaCrO44

return

55

Solid DecompositionSolid Decomposition

(NH(NH44))22CrCr22OO77(s)(s) Cr Cr22OO33(s) + 4H(s) + 4H22O(g) + NO(g) + N22(g)(g)

CuSOCuSO44..5H5H22OO

CuSOCuSO44 + 5H + 5H22O(g)O(g)

return

2NI2NI33 N22 + 3I + 3I22

66

Gas BubblesGas Bubbles

Ca + 2HCa + 2H22O O Ca(OH) Ca(OH)22 + H + H22(g) (g) Cr + 2HCr + 2H++ Cr Cr2+2+ + H + H22(g)(g)

Mg + 2HCl Mg + 2HCl MgClMgCl22 + H + H22

return

77

Fumes/Gas FormationFumes/Gas Formation

Cu + 4HNOCu + 4HNO33 Cu(NO Cu(NO33))22 + 2NO + 2NO22 + 2H + 2H22OO

2H2H22OO22 2H 2H22O + OO + O22

Zn + IZn + I2 2 ZnIZnI22

return

88

SmokeSmoke

2Al + 3Br2Al + 3Br22 2AlBr 2AlBr33 2Na + Cl2Na + Cl22 2NaCl 2NaCl PP44 + 5O + 5O22

PP44OO1010

return

99

FlamesFlames

2Na + Cl2Na + Cl22 2NaCl 2NaCl 2CrO2CrO33 + 3C + 3C22HH55OH OH

CrCr22OO33 + 3CH + 3CH33CHO + CHO +

3H3H22OO

return

1010

LightLight

2Fe + 3O2Fe + 3O22 Fe Fe22OO33

2CH2CH33OH + OOH + O22 2CO 2CO22 + + 4H4H22OO

2H2H22 + O + O22 2H2O return

04m18vd2.mov.lnk

1111

Temperature ChangeTemperature Change

Ba(OH)Ba(OH)22..8H8H22O + NHO + NH44ClCl

Thermite: Al + FeThermite: Al + Fe22OO33

return

1212

Color ChangeColor Change

ClCl22 + 2I + 2I-- 2Cl 2Cl-- + I + I22 Cu + 4HNOCu + 4HNO33

Cu(NOCu(NO33))22 + 2NO + 2NO22 + 2H + 2H22OO

return

1313

Crystal Formation/Solid DepositionCrystal Formation/Solid DepositionCrystal Formation/Solid DepositionCrystal Formation/Solid Deposition

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

Zn + SnZn + Sn2+2+ Zn Zn2+2+ + Sn + Sn

return

1414

Solid DissolutionSolid Dissolution

Mg(OH)Mg(OH)22 + 2HCl + 2HCl MgCl MgCl22 + 2H + 2H22O O

return

AgCl(s) + 2NHAgCl(s) + 2NH33(aq) (aq)

Ag(NHAg(NH33))22+ + + Cl+ Cl--

1515

SoundSound

Oxidation of sugarOxidation of sugar

FireworksFireworks

return

1616

ExplosionExplosion

DynamiteDynamite

Building DemolitionBuilding Demolition Whale RemovalWhale Removal return

1717

OdorOdor

Certain molecules, especially Certain molecules, especially those containing sulfur or those containing sulfur or nitrogen, have distinctive nitrogen, have distinctive odors.odors.

returnreturn

1818

Electrical ConductivityElectrical Conductivity

Ba(OH)Ba(OH)22 + H + H22SOSO44

returnreturn

1919

Density/VolumeDensity/Volume

Sugar + HSugar + H22SOSO44

returnreturn

2020

pH ChangepH Change

returnreturn

2121

Magnetic PropertiesMagnetic Properties

Fe + SFe + S88

2222

Generate ElectricityGenerate Electricity

Chemical Chemical reaction reaction in the in the batterybattery

returnreturn

2323

4.4 Observing and Predicting Reaction Patterns

4.4 Observing and Predicting Reaction Patterns

Predictions: Predictions: do an experimentdo an experiment use periodicityuse periodicity use classifications of use classifications of

reactionsreactionsexample: combustion example: combustion

reactions involve the reactions involve the reaction of an element reaction of an element or a compound with or a compound with oxygen, usually with oxygen, usually with the evolution of heatthe evolution of heat

2424

In the following particulate In the following particulate representations, a circle represents an representations, a circle represents an atom and different circles represent atom and different circles represent different elements. Using these different elements. Using these representations, draw pictures of all representations, draw pictures of all the different types of atomic/molecular the different types of atomic/molecular changes these substances could changes these substances could undergo.undergo.

Reaction ClassificationsReaction Classifications

AA BBBB CC DD EE FF

2525

Combination(or Synthesis)Combination(or Synthesis)

+

+

+

BBBB

CC DDEE FF

AA AA

AA AACC DD CC DD

CC DD

FF

EE

BBBB

2626

DecompositionDecomposition

+CC DD CC DD

EE FF EE FF +

2727

Single ReplacementSingle Replacement

+ +AACC DDAA DD CC

AA EEFFAA EE FF + +

2828

Double ReplacementDouble Replacement

+ +

1:30 1:30

CC DD EE FF CC FF EE DD

2929

Reactions in SolutionReactions in Solution Precipitation ReactionsPrecipitation Reactions

Reactions in SolutionReactions in Solution Precipitation ReactionsPrecipitation Reactions

compound 1 + compound 2 compound 1 + compound 2 compound 3 + compound 4 compound 3 + compound 4

Also called Also called double replacement or metathesisdouble replacement or metathesis reactions.reactions.

exchange of ionic partnersexchange of ionic partners

AB + CD AB + CD AD + CB AD + CB

Pb(NOPb(NO33))22(aq) + K(aq) + K22CrOCrO44(aq) (aq)

PbCrO PbCrO44(s) + 2KNO(s) + 2KNO33(aq)(aq)

And other related reactionsAnd other related reactions04m10vd104m10vd1

3030

ReactantsReactants ProductsProducts

Double-Replacement Double-Replacement Reactions (Metathesis)Reactions (Metathesis)Double-Replacement Double-Replacement

Reactions (Metathesis)Reactions (Metathesis)

3131

Precipitation ReactionsPrecipitation Reactions

Precipitation reactions: (An example of a Precipitation reactions: (An example of a "double replacement" or "metathesis" "double replacement" or "metathesis" reaction).reaction).

Precipitation Reactions form a solid when Precipitation Reactions form a solid when two solutions are combined. two solutions are combined.

An example is the combining aqueous An example is the combining aqueous potassium chromate with aqueous lead potassium chromate with aqueous lead nitrate to form the precipitate lead nitrate to form the precipitate lead chromate (still used in school bus paint!!)chromate (still used in school bus paint!!)

3232

Describing Reactions in Solution


To identify the precipitate or predict the To identify the precipitate or predict the formation of a precipitate the solubilities of formation of a precipitate the solubilities of compounds can be used. These rules should compounds can be used. These rules should already be memorized!already be memorized!

Table 4.1, pg 144Table 4.1, pg 144

3333

Solubility PrinciplesSolubility Principles

Most nitrate and acetate salts are soluble.Most nitrate and acetate salts are soluble.Most salts containing the alkali metal ions Most salts containing the alkali metal ions

(Li(Li++, Na, Na++, K, K++, Cs, Cs++, Rb, Rb++) and the ammonium ) and the ammonium ion (NHion (NH44

++) are soluble.) are soluble.

Most chloride, bromide and iodide salts are Most chloride, bromide and iodide salts are soluble. Notable exceptions are salts soluble. Notable exceptions are salts containing the ions Agcontaining the ions Ag++, Pb, Pb2+2+ and Hg and Hg22

2+2+..

3434

Solubility PrinciplesSolubility Principles

Most sulfate salts are soluble. Notable exceptions are Most sulfate salts are soluble. Notable exceptions are BaSOBaSO44, PbSO, PbSO44, HgSO, HgSO44 and CaSO and CaSO44..

Most hydroxide salts are only slightly soluble. Most hydroxide salts are only slightly soluble. Important soluble hydroxides are NaOH and KOH. Important soluble hydroxides are NaOH and KOH. Ca(OH)Ca(OH)22, Sr(OH), Sr(OH)22, and Ba(OH), and Ba(OH)22 are somewhat soluble*. are somewhat soluble*.

Most sulfide, carbonate, chromate, and phosphate salts Most sulfide, carbonate, chromate, and phosphate salts are only slightly soluble**.are only slightly soluble**.

* Note Group 2 trends : As you go down the group sulfate solubility decreases * Note Group 2 trends : As you go down the group sulfate solubility decreases and hydroxide solubility increases.and hydroxide solubility increases.

** Slightly soluble compounds will form precipitates using "normal" ** Slightly soluble compounds will form precipitates using "normal" concentrations.concentrations.

3535



For reactions involving ionic compounds, we For reactions involving ionic compounds, we can write the reaction as a can write the reaction as a molecular molecular equationequation (or formula equation). This shows (or formula equation). This shows the normal (complete) formulas of all the normal (complete) formulas of all compounds:compounds:

Example:Example:

KK22CrOCrO44(aq) + Pb(NO(aq) + Pb(NO33))22(aq) (aq) PbCrOPbCrO44(s) + 2 (s) + 2

KNOKNO33(aq) (aq)

3636



We can rewrite the same reaction as a We can rewrite the same reaction as a complete complete ionic equationionic equation - Shows a picture of all that - Shows a picture of all that actually occurs in solutionactually occurs in solution

strong electrolytes represented as ions in solutionstrong electrolytes represented as ions in solution weak and non- electrolytes still written in molecular weak and non- electrolytes still written in molecular

(non-ionized) aqeuous state.(non-ionized) aqeuous state. Example:Example:

2K2K++(aq) + CrO(aq) + CrO442-2-(aq) + Pb(aq) + Pb2+2+(aq) + 2NO(aq) + 2NO33

--(aq) (aq)

PbCrOPbCrO44(s) + 2 K(s) + 2 K++(aq) + 2 NO(aq) + 2 NO33--(aq)(aq)

3737



A A net ionic equationnet ionic equation includes only the includes only the solution components involved in the solution components involved in the reaction (spectator ions, which do not reaction (spectator ions, which do not undergo change, are omitted)undergo change, are omitted)

PbPb2+2+(aq) + CrO(aq) + CrO442-2-(aq) (aq) PbCrO PbCrO44(s)(s)

3838

StoichiometryStoichiometry

Stoichiometry of Precipitation Reactions – Stoichiometry of Precipitation Reactions – based on Chapter 3 stoichiometry concepts, based on Chapter 3 stoichiometry concepts, but using molarity (concentration) but using molarity (concentration) relationships.relationships.Practice with Chapter 3 & Molarity!Practice with Chapter 3 & Molarity!Sample: How many grams of lead(II) Sample: How many grams of lead(II)

hydroxide can be formed when 22.5 mL of hydroxide can be formed when 22.5 mL of 0.135 M Pb(NO0.135 M Pb(NO33))22 solution reacts with excess solution reacts with excess sodium hydroxide? (Hint: Use a BCA table).sodium hydroxide? (Hint: Use a BCA table).

3939

Acid-Base ReactionsAcid-Base Reactions

Definitions:Definitions:Arrhenius:Arrhenius:

Acid - forms Acid - forms HH++ ions in solution (e.g HCl) ions in solution (e.g HCl)Base - forms Base - forms OHOH-- ions in solution (e.g. NaOH) ions in solution (e.g. NaOH)

Brønsted-Lowry :Brønsted-Lowry :Acid - proton (HAcid - proton (H++) ) donordonor (e.g. HCl) (e.g. HCl)Base - proton Base - proton acceptoracceptor

e.g. NHe.g. NH33:: NHNH33 + H + H++ NH NH44++

4040


General reaction : General reaction :

Acid + base(metallic hydroxide) Acid + base(metallic hydroxide) salt + water salt + water (neutralization reaction)(neutralization reaction)

e.g. HCl and NaOHe.g. HCl and NaOH molecular equation : molecular equation :

HCl(aq) + NaOH(aq) HCl(aq) + NaOH(aq) H H22O(l) + NaCl(aq)O(l) + NaCl(aq)

complete ionic equation. : complete ionic equation. :

HH++(aq) + Cl(aq) + Cl--(aq) + Na(aq) + Na++(aq) + OH(aq) + OH--(aq) (aq)

HH22O(l) + NaO(l) + Na++(aq) + Cl(aq) + Cl--(aq)(aq)

net ionic equation: Hnet ionic equation: H++ (aq) + OH (aq) + OH-- (aq) (aq) H H22O (l)O (l)

4141

Acid-Base TitrationsAcid-Base Titrations

Acid-base titrations (volumetric analysis) – Acid-base titrations (volumetric analysis) – determine an unknown quantity through titration.determine an unknown quantity through titration. Titration involves adding a precisely measured volume Titration involves adding a precisely measured volume

of a solution of known concentration (the titrant) into a of a solution of known concentration (the titrant) into a solution containing the substance being analyzed (the solution containing the substance being analyzed (the analyte).analyte).

The titrant reacts with the analyte in a known manner, The titrant reacts with the analyte in a known manner, such as an acid-base reaction.such as an acid-base reaction.

4242

Acid-Base TitrationsAcid-Base Titrations

An indicator marks the equivalence point (or An indicator marks the equivalence point (or stoichiometric point) where just the right amount stoichiometric point) where just the right amount of titrant has been added to completely react with of titrant has been added to completely react with the analyte. the analyte.

The endpoint is where the indicator actually The endpoint is where the indicator actually changes color, which hopefully occurs near the changes color, which hopefully occurs near the equivalence point.equivalence point.

4343


Note the similarities to precipitation Note the similarities to precipitation reactions.reactions.

Acid-Base reactions are another variation Acid-Base reactions are another variation of a double replacement reaction. The key of a double replacement reaction. The key is the production of water.is the production of water.

Other common double replacement Other common double replacement reactions produce gases.reactions produce gases.

4444

Acid-Base StoichiometryAcid-Base Stoichiometry

There are numerous variations on the acid-There are numerous variations on the acid-base reaction. Be sure to read through the base reaction. Be sure to read through the many examples in Section 4.8. We will many examples in Section 4.8. We will consider these examples now from a consider these examples now from a “modeling” perspective.“modeling” perspective.

4545


You first want to examine the acid-base reaction You first want to examine the acid-base reaction (similar to predicting a precipitation reaction). (similar to predicting a precipitation reaction). Here are some general steps (they can and should Here are some general steps (they can and should vary depending on the problem):vary depending on the problem):

1.1. List the major species present in solution before the List the major species present in solution before the reaction occurs. Decide what reaction will occur (look for reaction occurs. Decide what reaction will occur (look for formation of water or gases)formation of water or gases)

2.2. Write a balanced equation. (leave space for a BCA table) Write a balanced equation. (leave space for a BCA table)

3. Calculate the moles of reactants. For solutions, use the 3. Calculate the moles of reactants. For solutions, use the volumes of the original solutions and their molarities volumes of the original solutions and their molarities (before mixing). Input into a BCA table.(before mixing). Input into a BCA table.

4646


4.4. Determine the limiting reactant if Determine the limiting reactant if appropriate.appropriate.

5.5. Analyze the problem and find the moles of Analyze the problem and find the moles of reactant or product asked for.reactant or product asked for.

6.6. Convert to grams or volume of solution if Convert to grams or volume of solution if asked forasked for

*All problems are different. Don’t “force” a *All problems are different. Don’t “force” a problem into a particular solution method.problem into a particular solution method.

4747

Reaction ClassesReaction ClassesCombination ReactionsCombination ReactionsReaction ClassesReaction Classes

Combination ReactionsCombination Reactions

element + element element + element compound compound metal + nonmetal metal + nonmetal ionic compound ionic compound

2Na(s) + Cl2Na(s) + Cl22(g) (g) 2NaCl(s) 2NaCl(s)

nonmetal + nonmetal nonmetal + nonmetal covalent cmpd covalent cmpd 2H2H22(g) + O(g) + O22(g) (g) 2H 2H22O(l)O(l)

Draw a molecular diagram of this Draw a molecular diagram of this type of reactiontype of reaction

03m10an103m10an1

01m11vd101m11vd101m11vd1.mov.lnk

4949

Combination: K + Cl2Combination: K + Cl2

5050

Reaction ClassesReaction ClassesAddition Reactions Addition Reactions Reaction ClassesReaction ClassesAddition Reactions Addition Reactions

element + compound element + compound compound compound

ClCl22 + 2TiCl + 2TiCl33 2TiCl 2TiCl44

ClCl22 + C + C22HH44 C C22HH44ClCl22

Draw a molecular diagram of this type of Draw a molecular diagram of this type of reactionreaction

5252

Reaction ClassesReaction ClassesDecomposition Reactions Decomposition Reactions

Reaction ClassesReaction ClassesDecomposition Reactions Decomposition Reactions

Compound Compound 2 elements or element + compound or 2 elements or element + compound or 2 compounds2 compounds

Oxides, peroxides Oxides, peroxides OO22

Nitrates Nitrates NONO22 or NO or NO22--

Carbonates Carbonates CO CO22

Hydrates Hydrates H H22OO

Ammonium salts Ammonium salts NH NH33

Draw a molecular diagram of this type of reactionDraw a molecular diagram of this type of reaction

04m03an104m03an1

CHMVID06CHMVID06volcano_1.mov.lnk

5353

Decomposition of HgODecomposition of HgO

5656

Reaction ClassesReaction ClassesSingle-Displacement Reactions Single-Displacement Reactions


element + cmpd element + cmpd cmpd + element cmpd + element(The more metallic element in the compound (The more metallic element in the compound is displaced.)is displaced.)

carbon + metal oxidescarbon + metal oxides 3C + Fe3C + Fe22OO33 3CO + 2Fe 3CO + 2Fe

metals + watermetals + water Ca(s) + 2HCa(s) + 2H22O(aq) O(aq) Ca(OH) Ca(OH)22(aq) + H(aq) + H22(g)(g)

5757

Single Displacement: Li + H2O

Single Displacement: Li + H2O

5959



metals + acidsmetals + acids

Fe(s) + 2HCl(aq) Fe(s) + 2HCl(aq) FeCl FeCl22(aq) + H(aq) + H22(g)(g)

04m05vd104m05vd1

6060

Reaction ClassesReaction ClassesSingle-Displacement ReactionsSingle-Displacement Reactions


metals + metal saltsmetals + metal salts

Zn(s) + SnClZn(s) + SnCl22(aq) (aq) ZnCl ZnCl22(aq) + Sn(s)(aq) + Sn(s)

04m16vd104m16vd1

6161

Single Displacement: Cu + AgNO3

Single Displacement: Cu + AgNO3

6262



nonmetals + saltsnonmetals + salts

ClCl22(aq) + 2KI(aq) (aq) + 2KI(aq) 2KCl(aq) + I 2KCl(aq) + I22(aq)(aq)

What do all these types of reactions have in What do all these types of reactions have in common???common???

6363

Oxidation-Reduction ReactionsOxidation-Reduction Reactions

reactions in which reactions in which electrons are transferredelectrons are transferredcauses a change in the charge of an ion or of causes a change in the charge of an ion or of

oxidation state of an element in a moleculeoxidation state of an element in a molecule

Oxidation states - Oxidation states - numbersnumbers assigned to assigned to elementselementsused to keep track of used to keep track of electronselectrons (not the same as (not the same as

charge, but related) charge, but related)

6464

Rules for Assigning Oxidation States (Table 4.2)


The oxidation state of an uncombined The oxidation state of an uncombined element is zero (includes diatomic elements element is zero (includes diatomic elements HH22,N,N22, O, O22, F, F22, Cl, Cl22, Br, Br22 and I and I22).).

The oxidation state of a monatomic ion is The oxidation state of a monatomic ion is the same as its charge (e.g. the sulfide ion, the same as its charge (e.g. the sulfide ion, SS2-2-, has an oxidation state of -2)., has an oxidation state of -2).

6565



Oxygen has an oxidation state of -2 in Oxygen has an oxidation state of -2 in covalent compounds (except in peroxides covalent compounds (except in peroxides (O(O22

2-2-) where each oxygen is assigned an ) where each oxygen is assigned an oxidation state of -1).oxidation state of -1).

In covalent compounds hydrogen is In covalent compounds hydrogen is assigned an oxidation state of +1. assigned an oxidation state of +1. (Hydrogen has a -1 charge in hydrides such (Hydrogen has a -1 charge in hydrides such as lithium hydride (LiH) or sodium hydride as lithium hydride (LiH) or sodium hydride (NaH).(NaH).

6666



In compounds, fluorine always has an oxidation In compounds, fluorine always has an oxidation state of -1.state of -1.

The sum of the oxidation states of the elements in The sum of the oxidation states of the elements in a neutral compound must equal zero.a neutral compound must equal zero.

The sum of the oxidation states of the elements in The sum of the oxidation states of the elements in a polyatomic ion must equal the charge on the a polyatomic ion must equal the charge on the polyatomic ion.polyatomic ion.

6767



Oxidation states may be non-integers. For Oxidation states may be non-integers. For

example in iron (III) oxide (Feexample in iron (III) oxide (Fe33OO44), the iron ), the iron

has an oxidation state of 8/3 (eight-thirds). has an oxidation state of 8/3 (eight-thirds).

6868

Rules for assigning oxidation states

Rules for assigning oxidation states

Practice: Identify the oxidation state of Practice: Identify the oxidation state of each atom in the following compounds:each atom in the following compounds:Magnesium nitrateMagnesium nitrateLithium nitrideLithium nitrideSodium nitriteSodium nitrite

6969

Characteristics of Redox Reactions

Characteristics of Redox Reactions

OxidationOxidation

a a lossloss of electrons of electrons

an an increaseincrease in oxidation state in oxidation state

the substance oxidized is the the substance oxidized is the reducing agentreducing agent (gives electrons (gives electrons to another substance)to another substance)

ReductionReduction

a a gaininggaining of electrons of electrons

a a decreasedecrease in oxidation state in oxidation state

the substance reduced is the the substance reduced is the oxidizing agentoxidizing agent (takes electrons (takes electrons away from another substance)away from another substance)

7070

Balancing Redox ReactionsBalancing Redox Reactions

By the half-reaction method :By the half-reaction method : In acidic solutionIn acidic solution1.1. Write separate oxidation and Write separate oxidation and

reduction reduction reactions for the reaction.reactions for the reaction.2.2. For each half reaction :For each half reaction :

balance all the elements balance all the elements except hydrogen and except hydrogen and oxygenoxygen

balance balance oxygenoxygen atoms using H atoms using H22OObalance balance hydrogenhydrogen atoms using H atoms using H++

balance the charge using balance the charge using electronselectrons

7171


3.3. If necessary, balance electrons lost and If necessary, balance electrons lost and gained in each half reaction by gained in each half reaction by

multiplying one or both half reactions multiplying one or both half reactions by an integer.by an integer.

4.4. AddAdd the half-reactions and the half-reactions and cancelcancel out out like species.like species.

5.5. Check to make sure charges and Check to make sure charges and elements are elements are balancedbalanced..

7272

Example 4.19Example 4.19

Potassium dichromate is a bright orange Potassium dichromate is a bright orange compound that can be reduced to a blue-compound that can be reduced to a blue-violet solution of chromium(III) ions. In violet solution of chromium(III) ions. In acidic conditions, potassium dichromate acidic conditions, potassium dichromate reacts with ethyl alcohol as follows:reacts with ethyl alcohol as follows:

CrCr22OO772-2-(aq) + C(aq) + C22HH55OH(l) OH(l) Cr Cr3+3+(aq) + CO(aq) + CO22(g) + H(g) + H22O(l)O(l)

Balance this equation using the half reaction Balance this equation using the half reaction method.method.

7373


In Basic solution (see example 4.20)In Basic solution (see example 4.20)::

1.1. Balance as in an acidic solution (see above).Balance as in an acidic solution (see above).

2.2. Add a number of OH- ions equal to the H+ Add a number of OH- ions equal to the H+ ions present to both sides of each half ions present to both sides of each half

reaction to for Hreaction to for H22O.O.

3.3. Eliminate the number of HEliminate the number of H22O molecules that O molecules that appear on both sides of the equation.appear on both sides of the equation.

4.4. Check to make sure charges and elements Check to make sure charges and elements are balanced.are balanced.

7474

Group (Partner) QuizGroup (Partner) Quiz

1.1. Give the oxidation state of each element in sodium Give the oxidation state of each element in sodium chlorate (NaClOchlorate (NaClO33))

2.2. In the following reaction, identify the oxidizing In the following reaction, identify the oxidizing agent, the reducing agent, the substance being agent, the reducing agent, the substance being oxidized, and the substance being reducedoxidized, and the substance being reduced

Br Br – – (aq) + MnO(aq) + MnO44--(aq) (aq) Br Br22(l) + Mn(l) + Mn2+2+(aq)(aq)

3.3. Balance the above RedOx reaction that occurs in Balance the above RedOx reaction that occurs in acidic solution.acidic solution.

7575

Classify the following reactions, based on the

changes happening at an atomic/molecular level. Classify the following reactions, based on the

changes happening at an atomic/molecular level. 1. AlF1. AlF33(aq) + 3H(aq) + 3H22O(l) O(l) Al(OH) Al(OH)33(s) + 3HF(aq) (s) + 3HF(aq)

2. BaCl2. BaCl22(aq) + Na(aq) + Na22SOSO44(aq) (aq) BaSO BaSO44(s) + 2NaCl(aq)(s) + 2NaCl(aq)

3. Ca(OH)3. Ca(OH)22(s) (s) CaO(s) + H CaO(s) + H22O(g)O(g)

4. Ca(s) + 2H4. Ca(s) + 2H22O(l) O(l) Ca(OH) Ca(OH)22(aq) + H(aq) + H22(g)(g)

5. CaO(s) + CO5. CaO(s) + CO22(g) (g) CaCO CaCO33(s)(s)

6. Cl6. Cl22(aq) + 2NaI(aq) (aq) + 2NaI(aq) 2NaCl(aq) + I 2NaCl(aq) + I22(aq)(aq)

7. Cu(s) + 2AgNO7. Cu(s) + 2AgNO33(aq) (aq) Cu(NO Cu(NO33))22(aq) + 2Ag(s)(aq) + 2Ag(s)

8. Fe(s) + 2HCl(aq) 8. Fe(s) + 2HCl(aq) FeCl FeCl22(aq) + H(aq) + H22(g)(g)

9. H9. H22SOSO33(aq) (aq) H H22O(l) + SOO(l) + SO22(g)(g)

10. 2HgO(s) 10. 2HgO(s) 2Hg(l) + O 2Hg(l) + O22(g)(g)

11. KOH(aq) + HNO11. KOH(aq) + HNO33(aq) (aq) KNO KNO33(aq) + H(aq) + H22O(l)O(l)

12. 4Li(s) + O12. 4Li(s) + O22(g) (g) 2Li 2Li22O(s)O(s)

13. Na13. Na22S(aq) + 2HCl(aq) S(aq) + 2HCl(aq) 2NaCl(aq) + H 2NaCl(aq) + H22S(g)S(g)

14. NH14. NH33(g) + HCl(g) (g) + HCl(g) NH NH44Cl(s)Cl(s)

15. NiCO15. NiCO33(s) (s) NiO(s) + CO NiO(s) + CO22(g)(g)

16. P16. P44(s) + 10F(s) + 10F22(g) (g) 4PF 4PF55(g)(g)

double displacementdouble displacementdouble displacementdouble displacementdecompositiondecompositionsingle displacementsingle displacementcombinationcombinationsingle displacementsingle displacementsingle displacementsingle displacementsingle displacementsingle displacementdecompositiondecompositiondecompositiondecompositiondouble displacementdouble displacementcombinationcombinationdouble displacementdouble displacementcombinationcombinationdecompositiondecompositioncombinationcombination

1 Ch. 4 Patterns of Chemical Reactivity lDemo: Pour together two clear colorless liquids lDid a...

Documents

Transcript of 1 Ch. 4 Patterns of Chemical Reactivity lDemo: Pour together two clear colorless liquids lDid a...