What is the difference between a What is the difference between a chemical reaction and physical chemical reaction and physical change?change?

When you watch a reaction When you watch a reaction occur, what are some hints that occur, what are some hints that it is a chemical reaction?it is a chemical reaction?

Ch. 11 Chemical Ch. 11 Chemical Equations ReactionsEquations Reactions

Describing Chemical Describing Chemical ReactionsReactions

ObjectivesObjectives

List three observations that suggest List three observations that suggest that a chemical reaction has taken that a chemical reaction has taken place.place.

List three requirements for a List three requirements for a correctly written chemical equation.correctly written chemical equation.

Write a word equation and a formula Write a word equation and a formula equation for a given reaction.equation for a given reaction.

Balance a formula equation by Balance a formula equation by inspection.inspection.

Chemical ReactionsChemical Reactions

when a substance when a substance changes identitychanges identity reactants- originalreactants- original products- resultingproducts- resulting

law of conservation law of conservation of massof mass total mass of reactants total mass of reactants

= total mass of products= total mass of products

Chemical ReactionsChemical Reactions

chemical equationchemical equation represents identities and relative represents identities and relative

amounts of reactants and products in amounts of reactants and products in the chemical reactionthe chemical reaction

uses symbols and formulasuses symbols and formulas

Hints of Chemical RxnHints of Chemical Rxn

heat or lightheat or light can also happen with can also happen with

physical changesphysical changes gas bubblesgas bubbles

means a gas is being means a gas is being created as productcreated as product

precipitateprecipitate solid is being createdsolid is being created

color changecolor change

Writing Chemical EquationsWriting Chemical Equations

most pure elementsmost pure elements written as elemental symbolwritten as elemental symbol

diatomic moleculesdiatomic molecules molecule containing only 2 molecule containing only 2

atomsatoms some elements normally exist some elements normally exist

this waythis way HH22, O, O22, N, N22, F, F22, Cl, Cl22, Br, Br22, I, I22

other exceptionsother exceptions

• sulfur: Ssulfur: S88

• phosphorus: Pphosphorus: P44

Word EquationsWord Equations

uses names instead of formulasuses names instead of formulas helps you to write formula equationhelps you to write formula equation

ExampleExample

Description:Description:

Solid sodium oxide is added to water Solid sodium oxide is added to water at room temperature and forms at room temperature and forms sodium hydroxide.sodium hydroxide.

Word Equation:Word Equation:sodium oxide + water sodium oxide + water sodium hydroxide sodium hydroxide

Formula Equation:Formula Equation:

NaNa22O + HO + H22O O NaOH NaOH

Symbols Used in EquationsSymbols Used in Equations

yieldsyields

reversible reversible

above arrow:above arrow:

oror heat heat heatedheated

MnOMnO22 or or PtPt catalystcatalyst

25°C25°C specific T specific T requirementrequirement

2 atm2 atm specific P specific P requirementrequirement

after a after a formula:formula:

(s)(s) solidsolid

(l)(l)liquidliquid

(aq)(aq) aqueous: aqueous: dissolved dissolved

in in waterwater

(g)(g) gasgas

Text Pg. 323 Chart of Text Pg. 323 Chart of symbols used in symbols used in chemical equationschemical equations

List three observations that suggest List three observations that suggest that a chemical reaction has taken that a chemical reaction has taken place.place.

Acids you have to know!Acids you have to know!

HCl hydrochloric acidHCl hydrochloric acidHH22SOSO44 sulfuric acid sulfuric acid

HNOHNO33 nitric acid nitric acid

HH33POPO44 phosphoric acid phosphoric acid

HCHC22HH33OO22 acetic acid acetic acid

Write the chemical equation Write the chemical equation from the following description:from the following description:Zinc metal is added to hydrochloric Zinc metal is added to hydrochloric acid to create zinc chloride and acid to create zinc chloride and hydrogen gas. hydrogen gas.

Aluminum reacts with Aluminum reacts with oxygen to produce oxygen to produce

aluminum oxidealuminum oxide

A.A. Al + O Al + O Al Al22OO33

B.B. Al + OAl + O22 Al Al22OO33

C.C. AlAl33 + O + O Al Al22OO33

Aluminum reacts with Aluminum reacts with oxygen to produce oxygen to produce

aluminum oxidealuminum oxide

A.A. Al + O Al + O Al Al22OO33

B.B. Al + OAl + O22 Al Al22OO33

C.C. AlAl33 + O + O Al Al22OO33

Phosphoric acid is produced Phosphoric acid is produced through the reaction through the reaction

between tetraphosphorus between tetraphosphorus decoxide and waterdecoxide and water

A.A. HH33POPO44 P P44 + H + H22OOB.B. HH33POPO4 4 + H+ H22O O P P44

C.C. PP44OO10 10 + H+ H22O O H H33POPO44

Phosphoric acid is produced Phosphoric acid is produced through the reaction through the reaction

between tetraphosphorus between tetraphosphorus decoxide and waterdecoxide and water

A.A. HH33POPO44 P P44 + H + H22OOB.B. HH33POPO4 4 + H+ H22O O P P44

C.C. PP44OO10 10 + H+ H22O O H H33POPO44

Iron(III)oxide reacts with Iron(III)oxide reacts with carbon monoxide to carbon monoxide to

produce iron and carbon produce iron and carbon dioxidedioxide

A.A. FeO + CO FeO + CO Fe + CO Fe + CO22

B.B. FeFe22OO33 + CO + CO Fe + CO Fe + CO22

C.C. Fe + COFe + CO Fe Fe22OO33 + CO + CO22

Iron(III)oxide reacts with Iron(III)oxide reacts with carbon monoxide to carbon monoxide to

produce iron and carbon produce iron and carbon dioxidedioxide

A.A. FeO + CO FeO + CO Fe + CO Fe + CO22

B.B. FeFe22OO33 + CO + CO Fe + CO Fe + CO22

C.C. Fe + COFe + CO Fe Fe22OO33 + CO + CO22

CoefficientsCoefficients

whole numbers in front of formulawhole numbers in front of formula distributes to numbers of atoms in distributes to numbers of atoms in

formulaformula specifies the relative number of moles specifies the relative number of moles

and molecules involved in the reactionand molecules involved in the reaction used to balance the equationused to balance the equation

Balancing EquationsBalancing Equations ONLY add/change coefficients- ONLY add/change coefficients-

NEVER subscripts!!!NEVER subscripts!!!

1.1. balance one type of atom at a timebalance one type of atom at a time

2.2. balance polyatomic ions firstbalance polyatomic ions first

3.3. balance atoms that appear only balance atoms that appear only once secondonce second

4.4. balance H and O lastbalance H and O last

5.5. simplify if you cansimplify if you can

6.6. Check at end!Check at end!

Rules for writing and Rules for writing and balancing equations – balancing equations – Pg. 327 in text.Pg. 327 in text.

Writing EquationsWriting Equations Write Word equations to help you Write Word equations to help you

organize reactants and productsorganize reactants and products Be sure to include symbols showing Be sure to include symbols showing

states of each reactant and productstates of each reactant and product Be sure to write the correct formula Be sure to write the correct formula

for each (crossing over for ionic for each (crossing over for ionic compounds!)compounds!)

Check your balancing of the Check your balancing of the equation when you are finishedequation when you are finished

Example 1Example 1

Description:Description: Aqueous iron III oxide reacts with Aqueous iron III oxide reacts with

hydrogen gas to produce iron metal hydrogen gas to produce iron metal and liquid waterand liquid water

Word Equation:Word Equation:

Iron III oxide + hydrogen gas Iron III oxide + hydrogen gas

iron + wateriron + water

Example 1Example 1

Formula Equation:Formula Equation:

FeFe22OO3 3 (aq) (aq) + H+ H22 (g)(g) Fe Fe (s)(s) + H + H22O O

(l)(l)

Balanced Formula EquationBalanced Formula Equation

FeFe22OO33 (aq) (aq) + 3H+ 3H22 (g)(g) 2Fe 2Fe (s)(s) + 3H + 3H22O O (l)(l)

Example 2Example 2

Solid calcium metal reacts with water Solid calcium metal reacts with water to form aqueous calcium hydroxide to form aqueous calcium hydroxide and hydrogen gas.and hydrogen gas.

calcium + water calcium + water

calcium hydroxide + calcium hydroxide + hydrogenhydrogen

CaCa(s)(s) + H + H22OO(l)(l) Ca(OH) Ca(OH)2(aq)2(aq) + H + H2(g)2(g)

CaCa(s)(s) + 2H + 2H22OO(l)(l) Ca(OH) Ca(OH)2(aq) 2(aq) + H+ H2(g)2(g)

Example 3Example 3

solid zinc metal reacts with aqueous solid zinc metal reacts with aqueous copper (II) sulfate to produce solid copper (II) sulfate to produce solid copper metal and aqueous zinc sulfatecopper metal and aqueous zinc sulfate

zinc + copper (II) sulfate zinc + copper (II) sulfate

copper + zinc sulfatecopper + zinc sulfate ZnZn(s)(s) + CuSO + CuSO4 4 (aq) (aq) Cu Cu (s)(s) + ZnSO + ZnSO4 4 (aq)(aq)

ZnZn(s)(s) + CuSO + CuSO4 4 (aq) (aq) Cu Cu(s)(s) + ZnSO + ZnSO4 4 (aq)(aq)

Example 4Example 4

Hydrogen peroxide in an Hydrogen peroxide in an aqueous solution aqueous solution decomposes to produce decomposes to produce oxygen and wateroxygen and water

hydrogen peroxide hydrogen peroxide oxygen + wateroxygen + water

HH22OO2 (aq) 2 (aq) O O2 (g)2 (g) + H + H22O O (l)(l)

2H2H22OO2 (aq) 2 (aq) O O2 (g)2 (g) + 2H + 2H22O O (l)(l)

Example 5Example 5

Solid copper metal reacts with Solid copper metal reacts with aqueous silver nitrate to produce aqueous silver nitrate to produce solid silver metal and aqueous solid silver metal and aqueous copper (II) nitratecopper (II) nitrate

copper + silver nitrate copper + silver nitrate silver + copper (II) silver + copper (II)

nitratenitrate Cu Cu (s)(s) + AgNO + AgNO3 (aq) 3 (aq) Ag Ag (s)(s) + Cu(NO + Cu(NO33))2 (aq)2 (aq)

Cu Cu (s)(s) + 2AgNO + 2AgNO3 (aq) 3 (aq) 2Ag 2Ag (s)(s) + Cu(NO + Cu(NO33))2 (aq)2 (aq)

Example 6Example 6

Carbon dioxide gas is bubbled through Carbon dioxide gas is bubbled through water containing solid barium carbonate, water containing solid barium carbonate, creating aqueous barium bicarbonatecreating aqueous barium bicarbonate

carbon dioxide + water + barium carbon dioxide + water + barium carbonate carbonate barium bicarbonate barium bicarbonate

COCO2 (g)2 (g) + H + H22O O (l)(l) + BaCO + BaCO3 (s)3 (s) Ba(HCO Ba(HCO33))2 2 (aq)(aq)

COCO2 (g)2 (g) + H + H22O O (l)(l) + BaCO + BaCO3 (s)3 (s) Ba(HCO Ba(HCO33))2 2 (aq)(aq)

Example 7Example 7 Acetic acid solution is added to a solution of Acetic acid solution is added to a solution of

magnesium bicarbonate to create water, magnesium bicarbonate to create water, carbon dioxide gas, and aqueous carbon dioxide gas, and aqueous magnesium acetate.magnesium acetate.

acetic acid + magnesium bicarbonate acetic acid + magnesium bicarbonate water + carbon dioxide + magnesium acetatewater + carbon dioxide + magnesium acetate HCHHCH33COO COO (aq) (aq) + Mg(HCO+ Mg(HCO33))2 2 (aq) (aq)

HH22OO(l)(l) + CO + CO2 (g)2 (g) + Mg(CH + Mg(CH33COO)COO)2 2 (aq)(aq)

2HCH2HCH33COO COO (aq) (aq) + Mg(HCO+ Mg(HCO33))2 (aq) 2 (aq)

2H2H22OO(l)(l) + 2CO + 2CO2 2 (g)(g) + Mg(CH + Mg(CH33COO)COO)2 2 (aq)(aq)

Write the Write the balancedbalanced formula equation formula equation for:for:

Lithium metal is added to a solution Lithium metal is added to a solution of aluminum sulfate to make of aluminum sulfate to make aqueous lithium sulfate and aqueous lithium sulfate and aluminum metal.aluminum metal.

Types of Chemical Types of Chemical ReactionsReactions

Types of Chemical Types of Chemical ReactionsReactions

5 basic types discussed here5 basic types discussed here not all reactions fall in these not all reactions fall in these

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

categorize a reaction categorize a reaction predict the product(s)predict the product(s)

1. Synthesis1. Synthesis

also called combination reactionalso called combination reaction reactants:reactants:

more than onemore than one can be elements or compoundscan be elements or compounds

products: only one compoundproducts: only one compound

A + X A + X AX AX

where A is the cation and X is anionwhere A is the cation and X is anion

1. Synthesis1. Synthesis

Rubidium and sulfurRubidium and sulfur

Rb Rb (s)(s) + S + S8 (s)8 (s) Rb Rb22S S (s)(s)

Magnesium and oxygenMagnesium and oxygen

Mg Mg (s)(s) + O + O2 (g)2 (g) MgO MgO (s)(s)

Sodium and chlorineSodium and chlorine

Na Na (s)(s) + Cl + Cl2 (g)2 (g) NaCl NaCl (s)(s)

Magnesium and fluorineMagnesium and fluorine

Mg Mg (s)(s) + F + F2 (g)2 (g) MgF MgF2 (s)2 (s)

1. Synthesis1. Synthesis

calcium oxide and watercalcium oxide and water

CaOCaO(s)(s) + H + H22OO(l)(l) Ca(OH) Ca(OH)2 (aq)2 (aq)

sulfur dioxide and watersulfur dioxide and water

SOSO2 (g)2 (g) + H + H22O O (l)(l) H H22SOSO3 (aq)3 (aq)

calcium oxide and sulfur dioxidecalcium oxide and sulfur dioxide

CaO CaO (s)(s) + SO + SO2 (g)2 (g) CaSO CaSO3 (s)3 (s)

2. Decomposition2. Decomposition

opposite of synthesisopposite of synthesis usually require energyusually require energy reactants: only one compoundreactants: only one compound products: more than oneproducts: more than one

usually elements but can be compoundsusually elements but can be compounds

AX AX A + X A + X

2. Decomposition2. Decomposition waterwater

HH22O O (l)(l) H H2 (g)2 (g) + O + O2 (g)2 (g)

calcium carbonatecalcium carbonate

CaCOCaCO3 (s)3 (s) CaO CaO (s)(s) + CO + CO2 (g)2 (g)

calcium hydroxidecalcium hydroxide

Ca(OH)Ca(OH)2 (s)2 (s) CaO CaO (s)(s) + H + H22O O (l)(l)

carbonic acidcarbonic acid

HH22COCO3 (aq) 3 (aq) CO CO2 (g)2 (g) + H + H22O O (l)(l)

3. Single Replacement3. Single Replacement

an element replaces a similar an element replaces a similar element in a compoundelement in a compound

reactants: 1 element & 1 compoundreactants: 1 element & 1 compound products: 1 element & 1 compoundproducts: 1 element & 1 compound

A + BX A + BX B + AX B + AX

Y + AX Y + AX X + AY X + AY

3. Single Replacement3. Single Replacement zinc and hydrochloric acidzinc and hydrochloric acid

Zn Zn (s)(s) + HCl + HCl (aq) (aq) ZnCl ZnCl2 (aq) 2 (aq) + H+ H2 (g)2 (g)

iron and wateriron and water

Fe Fe (s)(s) + H + H22O O (l)(l) FeO FeO (aq) (aq) + H+ H2 (g)2 (g)

magnesium and lead (II) nitratemagnesium and lead (II) nitrate

Mg Mg (s)(s) + Pb(NO + Pb(NO33))2 (aq) 2 (aq) Mg(NO Mg(NO33))3 (aq) 3 (aq) + Pb + Pb (s)(s)

chlorine and potassium bromidechlorine and potassium bromide

ClCl2 (g)2 (g) + KBr + KBr (s)(s) KCl KCl (s)(s) + Br + Br2 (g)2 (g)

4. Double Replacement4. Double Replacement

two similar elements switch placestwo similar elements switch places reactants: 2 compoundsreactants: 2 compounds products: 2 compounds products: 2 compounds

AX + BY AX + BY BX + AY BX + AY

4. Double Replacement4. Double Replacement barium chloride and sodium sulfatebarium chloride and sodium sulfate

BaClBaCl2 (aq) 2 (aq) + Na+ Na22SOSO4 (aq) 4 (aq) NaCl NaCl (aq) (aq) + BaSO+ BaSO4 (s)4 (s)

iron sulfide and hydrochloric acidiron sulfide and hydrochloric acid

FeS FeS (aq) (aq) + HCl + HCl (aq) (aq) FeCl FeCl2 (aq) 2 (aq) + H+ H22S S (g)(g)

hydrochloric acid and sodium hydroxidehydrochloric acid and sodium hydroxide

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

potassium iodide and lead (II) nitratepotassium iodide and lead (II) nitrate

KI KI (aq) (aq) + Pb(NO+ Pb(NO33))2 (aq)2 (aq) KNO KNO3 (aq) 3 (aq) + PbI+ PbI2 (s)2 (s)

5. Combustion5. Combustion

Only responsible for one typeOnly responsible for one type releases energy in form of heat/lightreleases energy in form of heat/light reactants: hydrocarbon + Oreactants: hydrocarbon + O22

HH22O and COO and CO2 2 as the only productsas the only products

Ex: CHEx: CH44 + O + O22 CO CO22 + H + H22OO

CombustionCombustion

propane and oxygenpropane and oxygen

CC33HH88(g) + O(g) + O22(g) (g) CO CO22(g) + H(g) + H22O(g)O(g)

PracticePractice

Classify each of the following reactions Classify each of the following reactions one of the five basic types:one of the five basic types:

NaNa22O + HO + H22O O NaOH NaOH synthesissynthesis

Zn Zn (s)(s) + 2HCl + 2HCl (aq) (aq) ZnCl ZnCl2 (aq) 2 (aq) + H+ H2 (g)2 (g)

single replacementsingle replacement

Ca Ca (s)(s) + 2H + 2H22O O (l)(l) Ca(OH) Ca(OH)2 (aq) 2 (aq) + H+ H2 (g)2 (g)

single replacementsingle replacement

PracticePractice

2H2H22OO2 (aq) 2 (aq) O O2 (g)2 (g) + 2H + 2H22O O (l)(l) decompositiondecomposition

Cu Cu (s)(s) + 2AgNO + 2AgNO3 (aq) 3 (aq) 2Ag 2Ag (s)(s) +Cu(NO +Cu(NO33))2 (aq)2 (aq) single replacementsingle replacement

CC22HH4 (g)4 (g) + O + O2 (g)2 (g) CO CO2 (g)2 (g) + H + H22O O (g)(g) combustioncombustion

ZnO ZnO (s)(s) + C + C (s)(s) 2Zn 2Zn (s)(s) + CO + CO2 (g)2 (g) single replacementsingle replacement

PracticePractice

NaNa22O O (s)(s) + 2CO + 2CO2 (g)2 (g) + H + H22O O (l)(l) NaHCO NaHCO3 (s)3 (s)

synthesissynthesis

CaCa(s)(s) + H + H22OO(l)(l) Ca(OH) Ca(OH)22 (aq) (aq) + H+ H2 (g)2 (g)

single replacementsingle replacement

KClOKClO3 (s)3 (s) KCl KCl (s)(s) + O + O2 (g)2 (g)

decompositiondecomposition

HH22SOSO4 (aq) 4 (aq) + BaCl+ BaCl2 (aq) 2 (aq) HCl HCl (aq) (aq) + BaSO+ BaSO4 (s)4 (s)

double replacementdouble replacement

Activity SeriesActivity Series

Activity Series Pg. 333Activity Series Pg. 333

ActivityActivity ability of an element to reactability of an element to react

easier it reacts, higher the activityeasier it reacts, higher the activity

activity seriesactivity series list of elements organized according to list of elements organized according to

activitiesactivities from highest to lowestfrom highest to lowest

Activity SeriesActivity Series

metalsmetals greater activity, easier to lose electronsgreater activity, easier to lose electrons easier to become a cationeasier to become a cation

nonmetalsnonmetals greater activity, easier to gain electronsgreater activity, easier to gain electrons easier to become an anioneasier to become an anion

Activity SeriesActivity Series

used to predict whether single used to predict whether single replacement reactions will occurreplacement reactions will occur

most active is on topmost active is on top

an element can replace anything below it an element can replace anything below it but not any above itbut not any above it

PracticePractice

zinc and hydrofluoric acidzinc and hydrofluoric acid Zn Zn (s)(s) + HCl + HCl (aq) (aq) ZnCl ZnCl2 (aq)2 (aq) + H + H2 (g)2 (g)

calcium and lead (II) nitratecalcium and lead (II) nitrate CaCa (s) (s) + Pb(NO + Pb(NO33))2 (aq)2 (aq) Ca(NO Ca(NO33))2 (aq) 2 (aq) + Pb+ Pb (s) (s)

copper and lithium sulfatecopper and lithium sulfate CuCu (s) (s) + Li + Li22SOSO4 (aq)4 (aq) no reaction no reaction

bromine and iron (II) chloridebromine and iron (II) chloride BrBr2 (l)2 (l) + FeCl + FeCl2 (aq)2 (aq) no reaction no reaction