Downloaded 512 times
![19.2
Cell Notation
Zn (s) + Cu2+
(aq) Cu (s) + Zn2+
(aq)
[Cu2+
] = 1 M & [Zn2+
] = 1 M
Zn (s) | Zn2+
(1 M) || Cu2+
(1 M) | Cu (s)
anode cathode
Zn (s)| Zn+2
(aq, 1M)| K(NO3) (saturated)|Cu+2
(aq, 1M)|Cu(s)
anode cathodeSalt bridge
More detail..](https://image.slidesharecdn.com/electrochemistry12-151027130043-lva1-app6892/85/Electrochemistry-12-70-320.jpg)
Uploaded byMak Tutorials
Electrochemistry 12
The document discusses redox reactions and electrochemistry, detailing the types of electrochemical cells, such as galvanic and electrolytic cells, along with their operations and examples. It covers concepts like conductance, cell potential, standard reduction potentials, and the relationship between electrochemical parameters and spontaneity of reactions. Additionally, it highlights practical applications, including batteries and fuel cells, underscoring their functioning principles.
More Related Content
Electrochemistry 12
- 1.
- 4. Loss of e Gainof e Reducing Agent Oxidising agent
- 5.
- 6.
- 7.
- 11. SnCl2(aq) + 2FeCl3(aq)→ SnCl4(aq) + 2FeCl2(aq) CuO(s) + H2(g) → Cu(s) + H2O(l) Example +2 +3 +4 +2 +100+2
- 12.
- 27. Also act asa conductor
- 32.
- 36. Metallic conductor dependupon • Nature and structure of metal. • No. of valence electron per atom. • Temperature of the sample.
- 40. conductivity aqueous solution dependupon • Nature of electrolyte. • Size of ion. • Solvation of ion. • Concentration of electrolytic. • Temperature.
- 48. One cell const.and resistivity Known then we can find value Easily.
- 49.
- 63.
- 65. Chemical to electricalElectrical to chemical
- 66. 2. Voltaic orGalvanic cells- An electrochemical cell in which a spontaneous reaction produces electricity. Eg. Dry cell, lead storage cell etc.
- 67. 1. Electrolytic cell- Anelectrochemical cell in which a non spontaneous reaction is forced to occur by passing a direct current from an external source into the solution. Eg. Refining metal(purify), electroplating & production of many chemical substance.
- 68. Gets Smaller -><- Gets Larger
- 69. Cell Notation 1. Anode 2.Salt Bridge 3. Cathode Anode | Salt Bridge | Cathode | : symbol is used whenever there is a different phase
- 70. 19.2 Cell Notation Zn (s)+ Cu2+ (aq) Cu (s) + Zn2+ (aq) [Cu2+ ] = 1 M & [Zn2+ ] = 1 M Zn (s) | Zn2+ (1 M) || Cu2+ (1 M) | Cu (s) anode cathode Zn (s)| Zn+2 (aq, 1M)| K(NO3) (saturated)|Cu+2 (aq, 1M)|Cu(s) anode cathodeSalt bridge More detail..
- 71. K(NO3) Zn (s) +2 H+ (aq) -> H2 (g) + Zn+2 (aq) Zn(s)| Zn+2 |KNO3|H+ (aq)|H2(g)|Pt
- 72. Electrochemical Cells 19.2 The differencein electrical potential between the anode and cathode is called: • cell voltage • electromotive force (emf) • cell potential 000 reductionoxidationCell EEE += UNITS: Volts Volt (V) = Joule (J) Coulomb, C
- 73. Standard Electrode Potentials 19.3 Standardreduction potential (E0 ) is the voltage associated with a reduction reaction at an electrode when all solutes are 1 M and all gases are at 1 atm. Ε0 = 0 V Standard hydrogen electrode (SHE) 2e− + 2Η+ (1 Μ) Η2 (1 atm) Reduction Reaction
- 75. Determining if RedoxReaction is Spontaneous • + E°CELL ; spontaneous reaction • E°CELL = 0; equilibrium • - E°CELL; nonspontaneous reaction More positive E°CELL ; stronger oxidizing agent or more likely to be reduced
- 76. Relating E0 Cell to∆G0 ech work ECell arg = Units work, Joule charge, Coulomb Ecell; Volts charge = nF Faraday, F; charge on 1 mole e- F = 96485 C/mole work = (charge)Ecell = -nFEcell ∆G = work (maximum) ∆G = -nFEcell
- 77. Relating Εο CELL tothe Equilibrium Constant, K ∆G0 = -RT ln K ∆G0 = -nFE0 cell -RT ln K = -nFE0 cell K nF RT ECell ln0 = ( ) 0257.0 96485 29831.8 = = mole C K molK J F RT K n K n ECell log 0592.0 ln 0257.00 ==
- 80. Effect of Concentrationon Cell Potential ∆G =∆G0 + RTlnQ ∆G0 = -nFE0 cell -nFEcell= -nFE0 cell +RTln Q Ecell= E0 cell - RTln Q nF Ecell= E0 cell - 0.0257ln Q n Ecell= E0 cell – 0.0592log Q n
- 81. Corrosion – Deteriorationof Metals by Electrochemical Process
- 82. Corrosion – Deteriorationof Metals by Electrochemical Process
- 83. Corrosion – Deteriorationof Metals by Electrochemical Process
- 85.
- 86.
- 88. Batteries 19.6 Leclanché cell Dry cell Zn(s) Zn2+ (aq) + 2e- Anode: Cathode: 2NH4 + (aq) + 2MnO2 (s) + 2e- Mn2O3 (s) + 2NH3 (aq) + H2O (l) Zn (s) + 2NH4 (aq) + 2MnO2 (s) Zn2+ (aq) + 2NH3 (aq) + H2O (l) + Mn2O3 (s)
- 89. Batteries Zn(Hg) + 2OH- (aq)ZnO (s) + H2O (l) + 2e- Anode: Cathode: HgO (s) + H2O (l) + 2e- Hg (l) + 2OH- (aq) Zn(Hg) + HgO (s) ZnO (s) + Hg (l) Mercury Battery 19.6
- 90. Batteries 19.6 Anode: Cathode: Lead storage battery PbO2 (s)+ 4H+ (aq) + SO4 2- (aq) + 2e- PbSO4 (s) + 2H2O (l) Pb (s) + SO4 2- (aq) PbSO4 (s) + 2e- Pb (s) + PbO2 (s) + 4H+ (aq) + 2SO4 2- (aq) 2PbSO4 (s) + 2H2O (l)
- 91. Fuel Cell vs.Battery • Battery; Energy storage device – Reactant chemicals already in device – Once Chemicals used up; discard (unless rechargeable) • Fuel Cell; Energy conversion device – Won’t work unless reactants supplied – Reactants continuously supplied; products continuously removed
- 92. Fuel Cell A fuelcell is an electrochemical cell that requires a continuous supply of reactants to keep functioning Anode: Cathode: O2 (g) + 2H2O (l) + 4e- 4OH- (aq) 2H2 (g) + 4OH- (aq) 4H2O (l) + 4e- 2H2 (g) + O2 (g) 2H2O (l)
- 93. Types of ElectrochemicalCells • Voltaic/Galvanic Cell; Energy released from spontaneous redox reaction can be transformed into electrical energy. • Electrolytic Cell; Electrical energy is used to drive a nonspontaneous redox reaction.
- 95. Faraday’s Constant Redox Eqn MolarMass Charge =(Current)(Time)
Editor's Notes
- #5 Oxidation means the loss of electrons (it does not always involve oxygen). Reduction means the gain of electrons (gaining of negatives, that is electrons, reduces the oxidation number of an atom.
- #8 When something oxidise another reduce. Electron one loose one accept. Oxidation cannot occure without reduction. Same aa ulta. I nan electrochemical cell both oxidation and reduction occur.
- #13 Resistivity (ρ) is defined as the electrical resistance when a sample is 1metre long with a cross-section of 1square metre. Resistivity is measured in ohm-metres. R = ρ l/AIf l = 1m and A = 1m2 R = ρ 1m/1m2 R = ρ Conductivity (κ) is the conductance of a material when it is 1metre long with a cross section of 1square metre. Conductivity is
- #14 Rbefore going to study conductivity of chemical cell first understand some key term.If l = 1m and A = 1m2 R = ρ 1m/1m2 R = ρ Conductivity (κ) is the conductance of a material when it is 1metre long with a cross section of 1square metre. Conductivity is
- #15 Electrical resistance of any current is directly proportional to l and A.
- #17 SI unit of resistivity is given 2nd point.
- #20 Conductance is inverse of resisitance.
- #21 Conductivity is donted by k called kappa. Greek
- #25 Denpending on there conductivity material are classified as conductore insulator semiconductor
- #31 Apart from this conductor there is one more conductor is called zero conductor.
- #32 Some metal alloy become super conductor at lower temperature. And some mix oxide at high temperature show super conductor.
- #35 Let us discuss about conductance electric conductance thrugh metal.
- #37 Metallic conductor depend upon
- #38 Conductivity also occure in pure water.
- #39 Pure water contain very less oh ion bcose of this pure water is very low conductivity.
- #40 By putting ioin concductivity increase.
- #42 To measure the ionic conductivity cell we use cell .
- #43 To calculate the distance btween two area is very difiicult. The column of the solution seperating the two electrode then has a resistance describe by eqn givwen.
- #44 G star show there cross section area.
- #45 If there is no conductivity we measure by resistance of the condcutivity.
- #47 Measurement of conductivity we can use witston bridge. Variable resistance R1. p detector show current flow. R2 is unknown resistance. O show AC power supply. When the bridge balance no flow though the detector. At this condition equation is R2=
- #48 Measure conductivity of solution and resistance of cell. One cell constant and resistivity known then.
- #51 We converting the unit result gets second equation.
- #52 As solution diluted only few ions remain that’s why decrease conductivity.
- #54 Strong electrolyte kam ion se bhi electricity conduct karega. But weak electrolyte already weak hai to wo electiricity conduct nahi karpayga.
- #57 You can clasiffy electrode based on charges form.
- #58 Limiting molar condivity = anion limiting molar condivity + cation liminting molar condivity z.
- #61 Weak electrolyte mean diluted solution so conductivity low. Only measure by kohrausch law or limiting conductivity.
- #62 For a weak electroly or disscociation const. alpha. If molar and limiting molar conductivity known then we find
- #66 Our fully focus on this chapter is voltaic cell.