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CHEMISTRYELECTROCHEMISTRYFORM 4

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What is the state for this subject?Liquid?Gas?Solid?4kimia.cikgupaatz.com

How about the ions in a solid?Free to move or no any free ions moving?How the particles arrangement in a solid?Can conduct electric??5kimia.cikgupaatz.com

How the particles being arranged in liquid?Ions?

Can conduct electric??6kimia.cikgupaatz.comMaterial which in solid form: No free ions moving = cannot conduct electric2. Material which in liquid or molten form: Contain free ions moving = can conduct electricWe can conclude that7kimia.cikgupaatz.comWe can conclude that

The people will attracted with each other through difference gender.At the same meaning, the substances will attracted together by difference charges.Such as, +ve ion -ve electrode -ve ion +ve electrodeAttracted by9kimia.cikgupaatz.com

-ve electrode?? ion+veO o o o o oExample:10kimia.cikgupaatz.comNON-ELECTROLYTESSubstances that cannot conduct electricity either in molten or in aqueous solutionEg : Sulphur , Alcohol

12kimia.cikgupaatz.comIONIC COMPOUNDSSOLID STATE-Do not conduct electricity-Ions are held in a lattice-Do not move freelyMELTED OR DISSOLVE-Can conduct electricity-Ions are free to move

13kimia.cikgupaatz.comWHICH ONE IS ELECTROLYTE& NON-ELECTROLYTEHNO3BENZENEMOLTENPbCl2SUGAR

14kimia.cikgupaatz.comELECTRODESA conductor which carries electric current in and out of the electrolyte during electrolysis

16kimia.cikgupaatz.comELECTROLYTIC CELL

ELECTRODESELECTOLYTEANODECATHODE+-17kimia.cikgupaatz.comPROCESS ELECTROLYSISSTAGE 1

Cations Cathode

Anions Anode

++++----18kimia.cikgupaatz.comCONTINUESTAGE 2Cations discharge at cathode- by accepting e- from cathode- cathode has excess of e-Anions discharge at anode - by donating e- to anode - anode has a lack e-

19kimia.cikgupaatz.comCONTINUEElectron flow from anode to cathode through the connecting wire in the external circuitWhen ions are discharged at the electrodes, they are form atoms or molecules

20kimia.cikgupaatz.comEXAMPLE

+-Molten Lead(II)Bromidee-e-e-e-e-e-e-Pb2+Pb Pb2+Br Br Br Br- Br- Br-e-e-e-e- e-e-21kimia.cikgupaatz.comEXPLAINATIONIon exist: Pb2+ and Br-Pb2+ move to cathodeBr- move to anodeCathode: Pb 2+ (l) + 2e-Pb (s)Anode : 2Br-(l) Br2(g) +2e-Overall equation: Pb2+ (l) +2Br-(l) Pb(s)+Br2(g)

22kimia.cikgupaatz.comLETS DO SOME EXAMPLE!!23kimia.cikgupaatz.comEXAMPLE

+-Molten Copper (II)ChlorideEQUATIONAT CATHODE??EQUATIONATANODE??ION EXIST??OVERALLEQUATION??

24kimia.cikgupaatz.comION EXISTCu2+

Cl-

25kimia.cikgupaatz.comAQUEOUS SOLUTION A solution produced when the compound is dissolved in water

30kimia.cikgupaatz.comCATIONS AND ANIONS IN AQUEOUS SOLUTIONAQUEOUSSOLUTIONAnions and CationsOf the compoundHydrogen ion, H+ and OH- from the partial dissociation of water solution

H2O (l) H+(aq)+OH-(aq)

31kimia.cikgupaatz.comCations Cathode

Anions Anode++++----REMEMBER THIS!!

32kimia.cikgupaatz.comAqueous solutionAnion (negative ion)Cation (positive ion)Sodium Chloride, NaCl solutionChloride ion, Cl-Hydroxide ion, OH-Sodium ion, Na+Hydrogen ion, H+Copper(ll) Sulphate, CuSO4 SolutionSulphate ion, SO42-Hydroxide ion, OH-Copper(ll) ion, Cu2+Hydrogen ion, H+Nitric acid, HNO3Nitrate ion, NO3- Hydroxide ion, OH-Hydrogen ion, H+EXAMPLE:

33kimia.cikgupaatz.comWHAT IONSEXIST??CuCl2 solutionH2SO4

NaClsolution

34kimia.cikgupaatz.comEXAMPLE

+-Sodium Chloridesolutione-e-e-e- e-e-Cl-OH-H+Na+35kimia.cikgupaatz.comTHE SELECTIVEDISCHARGE OF IONS DEPENDS ONTypes of Electrodes ConcentrationOf the ionsIn the Electrolyte Position of Ions inElectrochemicalseries36kimia.cikgupaatz.comELECTROCHEMICAL SERIESThe lower the position of an ion in the electrochemical series, the higher is the tendency of the ion to discharged

38kimia.cikgupaatz.comEXAMPLE

+-Sodium Chloridesolutione-e-e-e- e-e-Cl-OH-H+Na+39kimia.cikgupaatz.comEXPLAINATIONIONS EXIST : Na+, Cl-, H+, OH-

Na+ and H+ will move to cathode

Cl- and OH- will move to anode

40kimia.cikgupaatz.comCATHODE: 2H+ (aq) + 2e- H2(g)ANODE : 4OH-(aq) O 2(g) +2H2O (l) +4e-OVERALL EQUATION:4H+(aq)+4OH-(aq) O2(g)+2H2O(l) +2H2 (g)

EXPLAINATION

41kimia.cikgupaatz.comEXAMPLE

+-Copper (II)ChlorideSolutionION EXIST??EQUATIONATANODE??EQUATIONAT CATHODE??OVERALLEQUATION??42kimia.cikgupaatz.comCONCENTRATION OF IONS IN ELECTROLYTESAn ion that is more concentrated is preferably dischargedThe concentration of ions normally affects the choice of ions to be discharged at the anode onlyAt cathode is still determined by the position of the ion in the electrochemical series

47kimia.cikgupaatz.comEXAMPLE

+-e-e-e-e- e-e-Cl-OH-Cu2+H+Concentrated copper (II) chloride solution48kimia.cikgupaatz.comEXAMPLE:

ION EXIST: Cu2+, H+, Cl-, OH-Cl- and OH- will move to anodeCu2+ and H+ will move to cathode 49kimia.cikgupaatz.comEXAMPLE:ANODE: 2Cl- (aq) Cl2(g) + 2e-CATHODE: Cu2+ (aq) +2e- Cu(s)OVERALL EQUATION: 2Cl-(aq) + Cu2+(aq)Cl2(g)+Cu(s)

50kimia.cikgupaatz.comTYPES OF ELECTRODES USEDIf the type of metal used as the anode is similar to the type of metal ion which is found in the electrolyte solution, metal atoms (the anode) will lose electrons to form metal ions.

METAL ATOM METAL ION + e-51kimia.cikgupaatz.comTYPES OF ELECTRODESAt the cathode, metal ions will receive electrons and form metal atoms

METAL IONS + e- METAL ATOMS52kimia.cikgupaatz.comEXAMPLE

+-e-e-e-e- e-e-Ag+Silver nitrate solutionSilver electrodesAgAg53kimia.cikgupaatz.comEXAMPLE:IONS EXIST: Ag+, H+, NO3-,OH-ANODE: Ag(s) Ag+(aq)+ e-CATHODE: Ag+ (aq) + e- Ag(s)

54kimia.cikgupaatz.comEXAMPLEThe silver plate at anode dissolves become thinner At cathode, shiny grey silver solid, Ag is formed

55kimia.cikgupaatz.comELECTROLYSIS IN INDUSTRIES

EXTRACTIONOFMETALSPURIFICATION OFMETALSELECTROPLATINGOF METALS57kimia.cikgupaatz.comEXTRACTION OF METALSVery reactive metals can only be extracted from their ores by electrolysisExample :Aluminium from molten aluminium oxideSodium from molten sodium chloride

58kimia.cikgupaatz.comEXTRACTION OF ALUMINIUM

59kimia.cikgupaatz.comEXTRACTION OF ALUMINIUMAl2O3 is mixed with crolite,Na3AlF6 to lower the melting point of Al2O3Blocks of carbon AnodeCarbon lining Cathode

60kimia.cikgupaatz.comCathode : Al3+(l) + 3e- Al(l)Anode: 2O2-(l) O2(g) + 4e- Overall reaction: 2Al2O3 (l) 4Al(l) + 3O2 (g)

EXTRACTION OF ALUMINIUM

61kimia.cikgupaatz.comLiquid aluminium is denser than the electrolyte and will be collected at the bottom of the cellThe oxygen liberated at the anode will react with the carbon electrode to produces CO2C (s) + O2 (g) CO2(g)Anode is corroded slowly and must be replaced from time to timeEXTRACTION OF ALUMINIUM

62kimia.cikgupaatz.comEXTRACTION OF SODIUM

Cl2SodiumSteel (-)Steel (-)Graphite (+)Molten NaCl + CaCl2

63kimia.cikgupaatz.comNa is extracted from molten NaClNaCl is mixed with CaCl2 to lower the melting point of NaClSteel CathodeGraphite - AnodeEXTRACTION OF SODIUM

64kimia.cikgupaatz.comCathode Na+ (l) + e- Na (l)Anode 2Cl- (l) Cl2(g)+ 2 e-Overall chemical reaction 2NaCl (l) 2Na(l) + Cl2(g) EXTRACTION OF SODIUM

65kimia.cikgupaatz.comPurification of metals

66kimia.cikgupaatz.comImpure metals AnodePure metals CathodeElectrolyte used is an aqueous salt solutionCathodeThe pure copper electrode become thicker Cu 2+(aq) + 2e- Cu (s)Purification of metals

67kimia.cikgupaatz.comAnode The impure copper electrode dissolves into the solutionThe impurities fall to the bottom of the beakerThe anode become thinner Cu (s) Cu 2+ (aq) + 2e-

Purification of metals68kimia.cikgupaatz.comELECTROPLATING OF METALS

69kimia.cikgupaatz.comElectroplating is a process of depositing a layer of metal on another substance using electrolysisTo protect them from corrosion and give attractive appearanceCathode: object to be platedAnode: pure plating metalElectrolyte shall contain ions of the plating metalELECTROPLATING OF METALS

70kimia.cikgupaatz.comAnode : Copper Cu(s) Cu2+ (aq) + 2e-Cathode : Iron spoon Cu2+ (aq) + 2e- Cu(s)Observation:- A brown solid is deposited on the iron spoon- The copper electrode become thinner ELECTROPLATING OF METALS

71kimia.cikgupaatz.comGOOD QUALITY PLATNGThe metal object to be plated must be clean and free of greaseThe concentration of the ions of the plating metal must be lowThe electric current must be smallThe object to be plated must be turned steadily

72kimia.cikgupaatz.comVOLTAIC CELLA device which converts chemical energy to electrical energyMade by placing two different metals in contact with an electrolyteElectrodes are connected to a voltmeter, a galvanometer, or an electric bulb using connecting wires

74kimia.cikgupaatz.comSIMPLE VOLTAIC CELL

-+e-e-e-e- e-e-Electrolyte solutionConductors of different metalsV75kimia.cikgupaatz.comSIMPLE VOLTAIC CELLHas two different conductors which are immersed in electrolyte solutionMetals that are located higher up in the ECS acts as the negative terminals Metals located lower in the ECS will act as the positive terminalsAlso called galvanic cell

76kimia.cikgupaatz.comSIMPLE VOLTAIC CELLNegative terminals: - The metal electrode will release electrons and dissolves to form metal ionsPositive terminals: - The metal electrode will accept electrons and be discharged to form neutral atoms

77kimia.cikgupaatz.comexample

-+e-e-e-e- e-e-Sodium Chloride solutionVe-e-e-e-e-e-e-Magnesium electrodeCopper electrodesMg2+H+Mg2+Na+78kimia.cikgupaatz.comLETS DO SOME EXERCISES80kimia.cikgupaatz.comDaniell cells

VZinc platePorous potZinc sulphate solutionCopper plateCupper(II) Sulphatesolution82kimia.cikgupaatz.comEXPLAINATIONA Daniell cell is made of two electrodes of different type of metal immersed in two separate electrolyte

83kimia.cikgupaatz.comSALT BRIDGE & POROUS POTTo prevent the two electrolytes from mixingTo allow the flow of the ions so that the electric circuit is completed

84kimia.cikgupaatz.comexamples

VZinc platePorous potZinc sulphate solutionCopper plateCupper(II) Sulphatesolution85kimia.cikgupaatz.comEXPLAINTION:Zinc which is higher than Copper in the ECS release more easily e-Zn plate will dissolve, forming zinc ionsAt negative terminal: Zn (s) Zn2+(aq) + 2e-

86kimia.cikgupaatz.comCONTINUEThe e- then flow through the connecting wire towards the copper plate which act as positive terminal The copper plate become thicker gradually At the positive terminal :Cu2+ (aq) + 2e- Cu (s)

87kimia.cikgupaatz.comCONTINUEOverall reaction:Zn (s) + Cu2+ (aq) Zn2+(aq) +Cu (s)

The intensity of the blue color of the CuSO4 solution decrease as the concentration of Cu2+ ions decrease gradually The flow Of e- from the zinc plate to the copper plate produces an electric current. The voltmeter shows reading

88kimia.cikgupaatz.comOTHER CELL SYMBOLZn(s) I Zn2+ (aq) Cu2+(aq) I Cu(s)

89kimia.cikgupaatz.comDANIELL CELL

90kimia.cikgupaatz.comLETS DO SOME EXERCISES91kimia.cikgupaatz.comExercise 2

VMagnesium platePorous potMagnesium sulphate solutionIron plateIron(II) SulphatesolutionNEGATIVE TERMINAL??POSITIVETERMINAL??HALF EQUATION?

92kimia.cikgupaatz.comTYPES OF VOLTAIC CELLDRY CELLMERCURYCELLALKALINECELLNICKELCADMIUMCELLLEADACIDACCUMULATOR93kimia.cikgupaatz.comDRY CELL

94kimia.cikgupaatz.comUSED INTORCHESRADIOELECTRICAL TOYSCASSETTE PLAYERS

95kimia.cikgupaatz.comDRY CELLELECTRODES Carbon rod (+) Zinc casing (-)ELECTOLYTE Ammonium chloride pasteUSED IN Torches, radio, electrical toys

96kimia.cikgupaatz.comLEAD-ACID ACCUMULATOR

97kimia.cikgupaatz.comUSED INMOTOR VEHICLESCAR VEHICLES

98kimia.cikgupaatz.comELECTRODES Lead grid packed with lead (IV) Oxide (+) Lead plate (-)ELECTROLYTE Dilute sulphuric acid LEAD-ACID ACCUMULATOR

99kimia.cikgupaatz.comMERCURY CELL

100kimia.cikgupaatz.comUSED IN.

CAMERASWATCHESCALCULATORS101kimia.cikgupaatz.comELECTRODES Mercury (II) Oxide and carbon (+) Zinc powder (-)ELECTROLYTE Potassium hydroxide pasteMERCURY CELL

102kimia.cikgupaatz.comALKALINE CELL

103kimia.cikgupaatz.comUSED INCASETTE PLAYERELECTRICAL TOYSAPPLIANCES WHICH ARE IN USE FOR LONG PERIODS

104kimia.cikgupaatz.comELECTRODES Manganese (IV) oxide (+) Zinc (-)ELECTROLYTES Potassium hydroxideALKALINE CELL

105kimia.cikgupaatz.comNICKEL-CADMIUM CELL

106kimia.cikgupaatz.comUSED INCASETTE PLAYERSELECTRICAL TOYSRADIOS

107kimia.cikgupaatz.comELECTRODES Nickel (IV) Oxide (+) Cadmium (-)ELECTROLYTE Potassium hydroxide solutionNICKEL-CADMIUM CELL

108kimia.cikgupaatz.comCAN YOU CLASSIFY THE ADVANTAGES ANDDISADVANTAGES OFTHESE VOLTAIC CELL??DRY CELLALKALINECELLMERCURYCELLLEADACIDACCUMULATORNICKELCADMIUMCELL

109kimia.cikgupaatz.comCOMPARISON BETWEENELECTROLYTIC CELL&VOLTAIC CELL

110kimia.cikgupaatz.comELECTROLYTIC CELLVOLTAIC CELLSIMILARITIESContain electrolyte solutionContains electrodesInvolves chemical changes on the electrodes111kimia.cikgupaatz.comELECTROLYTIC CELLVOLTAIC CELLDIFFERENCESMADE OFELECTRIC CURRENTENERGY CHANGESCATHODEANODEREUIREMENT OF BATTREYTwo similar electrodes immersed in the electrolyteUsed to produce chemical reactionElectric energyChemical energyIs the negative terminalIs the positive terminalUse batteryTwo different electrodes immersed in the electrolyteProduced from chemical reactionChemical energy Electric energyIs the positive terminalIs the negative terminalDoes not use battery112kimia.cikgupaatz.comCation Anion K+F-Na+SO42-Ca2+NO3-Mg2+Cl-Al3+Br-Zn2+ I-Fe2+ OH-Sn2+Pb2+H+Cu2+Ag+

ELECTROCHEMICAL SERIESKalau Nak

Cari

Makan

Ali

Zainal

Fera

Suka

Pergi

Hutan

Curi

Anggur

Fly

Selalu

Nak

Keluar

Baru

Insaf

OhEASIER TO DISCHARGE114kimia.cikgupaatz.com KNaCaMgAlZn Fe SnPbCu Ag ELECTROCHEMICAL SERIESMORE ELECTROPOSITIVEEASE OF RELEASING ELECTRONS INCREASE115kimia.cikgupaatz.comMEANINGAn arrangement of metals based on the tendency of each metal atom to donate electron

116kimia.cikgupaatz.comCAN BE COSTRUCTED BASED ON:

THE POTENTIALDIFFERENCEBETWEEN TWOMETALSTHE ABILITYOF A METALTO DISPLACE ANOTHERMETAL FROMITS SALTSOLUTION117kimia.cikgupaatz.comPOTENTIAL DIFFERENCES BETWEEN TWO IONSThe greater the voltage produced by the cell, the further the two metals are in the ECSWhen a voltmeter shows a positive reading ,the metal that connected to the negative terminal of the voltmeter will be the negative terminal of the cell

118kimia.cikgupaatz.comCONTINUEThis metal is situated at a higher position in the ECS than the other metal

119kimia.cikgupaatz.comPREDICT THE NEGATIVE TERMINAL, POSITIVE TERMINAL AND CELL VOLTAGE 120kimia.cikgupaatz.comEXAMPLEMgZnPbCuAg3.0V1.1V0.4V0.5V121kimia.cikgupaatz.comMagnesium and silverMagnesium and zincZinc and leadZinc and silverLETS DO!!TERMINALPOSITIVETERMINALNEGATIVECELLVOLTAGE

122kimia.cikgupaatz.comABILITY OF A METAL TO DISPLACE ANOTHER METAL FORM SALTS SOLUTIONA metal is situated at a higher position in the ECS is able to displace a metal below I in the series from its salt solution

123kimia.cikgupaatz.comEXAMPLEZn(s) + Pb(NO3)2 (aq) Zn(N03)2 (aq) + Pb(s)

Zn(s) + CuSO4 (aq) ZnSO4(aq) +Cu(s)

Metal displacedMetal displaced124kimia.cikgupaatz.comTHE IMPORTANCESOF THEECSTHE TERMINALS OF A VOLTAICCELLTHE ABILITYOF A METALTO DISPLACE ANOTHERMETAL FROMITS SALTSOLUTIONTHE STANDARD CELL VOLTAGE125kimia.cikgupaatz.comThe metal which is situated at a higher position in the ECS will be negative terminal The metal which is situated at a lower position in the ECS will be positive terminal126kimia.cikgupaatz.comTHANK YOU

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