ELECTROCHEMISTRY Chapter 19, 4.9
|
|
- Jewel Wilkinson
- 5 years ago
- Views:
Transcription
1 ELECTROCHEMISTRY Chapter 19, 4.9 Overview of an Electrochemical Process at Constant T and P ΔG = ΔG o + RT ln Q = welec (maximum) Note: I below stands for current measured in amperes = qecell = ItEcell (exp lab) (E intensive parameter, q extensive) = nfecell (theory) or rearranging to the Nernst equation André-Marie Ampère Michael Faraday Ecell = E o cell (RT/nF) ln Q where E o cell = ΔG o / nf = E o cell ( /n) log Q (at 25 o C) 1. n determined by balancing redox equation 2. E o cell determined by E o of species being oxidized and E o of species being reduced (standard reduction potentials) 3. therefore only Q (reaction quotient) can change the voltage Oxidation - Reduction Reactions (4.9) oxidation reduction Balancing Redox Equations (half-reaction method,19.2) oxidation numbers, ON (in order of priority, 4.9) 1. Sum of the oxidation numbers of atoms in a neutral species is zero; in an ion the sum equals the ion charge. 2. Alkali metals (Group I) ON = 1, alkaline earth metals (Group II) ON = 2, Group III usually have ON = Fluorine ON = -1 always. Other halogens usually have ON = -1 except in compounds with oxygen or other halogens when the oxidation number can be positive (follows the trend in electronegativity). 4. Hydrogen has ON = 1 except in metal hydrides when the oxidation number is negative. 5. Oxygen usually has ON = -2 except in compounds with fluorine when the oxidation number can be positive and in compounds containing the O-O bond. For peroxides ON = -1.
2 - 2 - Steps in Balancing Oxidation-Reduction Equations by Half-Reaction Method (19.2) (use oxidation numbers and include electrons in half-reactions) (omit step d if oxidation numbers used with electrons) *for basic reactions neutralize H + with OH - *for basic reactions neutralize H + with OH - Basically two ways to balance: 1. start with electrons in half-reactions determined from oxidation numbers OR 2. use electrons to balance charge after all elements are balanced *include these steps for a basic reaction EX 1. Balance in acidic solution MnO 4- (aq) + Fe(s) Mn 2+ (aq) + Fe 2+ (aq)
3 - 3 - EX 2. Balance in basic solution Ag(s) + CN - (aq) + O 2(g) Ag(CN) 2(aq) disproportionation (p. 1081) EX 3. Balance HNO 2 NO NO Electrochemical Cells (19.3, Figure 19.2) half-cells electrodes anode cathode electrolyte salt bridge FIG I - Terms Used in a Galvanic (Voltaic) Cell
4 - 4 - types of electrochemical cells ΔG = welec(max) = nfecell 1. spontaneous: ΔG < 0, Ecell> 0 2. nonspontaneous: ΔG > 0, Ecell < 0 FIG II- Electrochemical Cells (Figure 19.22) Luigi Galvani Alessandro Volta a) spontaneous: galvanic (voltaic) b) nonspontaneous: electrolytic OXIDATION half-reaction: Sn(s) Sn 2+ (aq) + 2e - REDUCTION half-reaction: Cu 2+ (aq) + 2e - Cu(s) OVERALL: Cu 2+ (aq) + Sn(s) Cu(s) + Sn 2+ (aq) OXIDATION half-reaction: Cu(s) Cu 2+ (aq) + 2e - REDUCTION half-reaction: Sn 2+ (aq) + 2e - Sn(s) OVERALL: Sn 2+ (aq) + Cu(s) Sn(s) + Cu 2+ (aq) electrochemical cell notation (cell diagram or line notation, p. 897) Cell Diagram or Line Notation for Galvanic Cells half-cell notation different phases separated by vertical lines species in same phase separated by commas types of electrodes active electrode involved in electrode half-reaction (most metal electrodes) ex: Zn 2+ /Zn metal electrode Zn(s) Zn 2+ (aq) + 2e - (oxidation) notation: Zn Zn 2+ inert electrode not involved in electrode half-reaction (inert solid conductors which serve to contact solution with external electrical circuit) ex: Pt electrode in Fe 3+ /Fe 2+ solution Fe 3+ (aq) + e - Fe 2+ (aq) (reduction) notation: Fe 3+, Fe 2+ Pt electrodes involving metals and their slightly soluble salts ex: Ag/AgCl electrode AgCl(s) + e - Ag(s) + Cl - (aq) (reduction) notation: Cl - AgCl Ag electrodes involving gases a gas is bubbled over an inert electrode ex: H 2 gas over Pt electrode H 2(g) 2H + (aq) + 2e - (oxidation) notation: Pt H 2 H + cell notation anode half-cell written to left of cathode half-cell (ordered way spontaneous reaction goes) electrodes appear on the far left (anode) and far right (cathode) in notation salt bridges represented by double vertical lines ex: Zn Zn 2+ and Fe 3+, Fe 2+ Pt half-cells Zn(s) Zn 2+ (aq) + 2e - (anode, oxidation) Fe 3+ (aq) + e - Fe 2+ (aq) [ 2] (cathode, reduction) Zn + 2Fe 3+ Zn Fe 2+ notation: Zn Zn 2+ Fe 3+, Fe 2+ Pt
5 - 5 - Cell Potential, Electrical Work, and Gibbs Free Energy (19.3, 19.5) electrical work electric current EX 4. A 6 volt battery delivers 1.25 amperes for 1.5 hours. How much work does the battery do? Electrolysis (19.8, stoichiometry of spontaneous/nonspontaneous reactions) EX 5. A galvanic (voltaic) electrochemical cell whose overall reaction is Cu(s) + 2 Ag + (aq) Cu 2+ (aq) + 2 Ag(s) oxidizes metallic copper at the anode dissolving the metal Cu(s) Cu 2+ (aq) + 2 e - and reduces silver ions in solution by plating them out as metallic silver at the cathode. Ag + (aq) + e - Ag(s) a) The cell delivers 0.1 A. How long does it take to dissolve 5.00 g of copper at the anode? (M Cu = ) b) An external power source is connected to the cell and the cell is run electrolytically. If the cell produces A for 101 minutes, how much copper is deposited and how much silver dissolves? (M Ag= g/mol)
6 - 6 - EX 6. An aqueous solution of a palladium salt is electrolyzed by 1.50 A for one hour which produces g of Pd at the cathode. What is the oxidation state of Pd? (M Pd = g/mol) Standard Electrode Potentials (19.4) standard states stable form (allotrope) at P = 1 atm and specified T (usually 25 C) pure solid pure liquid gas ideal gas behavior 1 molar (1 M) solution ideal solution behavior standard cell potential, E o there is no way to separately measure the potential of an oxidation or reduction halfreaction so conveniently define a zero for the scale standard reduction potential, E o by international convention, E o for the reduction of H + (aq) to give H2(g) is taken to be zero at all temperatures: 2 H + (aq, 1 M) + 2 e - H2(g, P = 1 atm) RED: 2H + (aq) + 2e - H 2(g) => H + (aq, 1 M) H 2(g, 1 atm) Pt OX: H 2(g) 2H + (aq) + 2e - => Pt H 2(g, 1 atm) H + (aq, 1 M) FIG IV SHE/Zinc FIG V SHE/Silver
7 - 7 - EX 7. Will Ag + oxidize Zn metal or will Zn 2+ oxidize metallic silver? strength of oxidizing agent strength of reducing agent EX 8. Find E o (Ag 2CrO 4 Ag) for the electrode and determine E o for the following reaction if E o (Fe 3+ Fe 2+ ) = V and ΔG o = kj for the reaction: K 2CrO 4(aq) + 2 Ag(s) + 2 FeC1 3(aq) Ag 2CrO 4(s) + 2 FeC1 2(aq) + 2 KCl(aq) Disproportionation and Oxidizing/Reducing Agents E o E o
8 - 8 - Cell Potential and Concentration (19.6) Walther Nernst The Nernst Equation Ecell = E o cell (RT/nF) ln Q = E o cell ( /n) log Q (25 o C); E o cell = E o cathode E o anode Half-Cells EX 9. Determine E for the hydrogen electrode: 2 H e - H 2 a) [H + ] = M, P H2 = atm b) H + + e - 1 / 2 H 2; [H + ] = M, P H2 = atm c) [H + ] = M, P H2 = 1.00 atm d) rewrite hydrogen electrode equation in base, [OH - ] = 1.00 M, P H2 = 1.00 atm EX 10. For the half reaction, Cu e - Cu, where, E o = V what is the reduction potential of the half-cell when [Cu 2+ ] = 0.10 M?
9 - 9 - Cells: EX 11. If [Cu 2+ ] = 0.10 M and [Ag + ] = 0.20 M, what is the voltage of an electrochemical cell based upon the couple: E o (Cu 2+ Cu) = V and E o (Ag + Ag) = V? EX 12. An electrochemical cell is based upon the couple: E o (Cu 2+ Cu) = V and E o (Ag + Ag) = V. If the voltage of the cell were V when [Cu 2+ ] = 0.10 M, what is the silver ion concentration? EX 13. If the cell voltage is V what is the ph of the cathode compartment for the following cell where E o (Zn 2+ Zn) = V? Zn(s) Zn 2+ (aq, 1.00 M) H + (aq,? M) H 2(g, 1 atm) Pt(s)
10 Cell Potential, Free Energy, and the Equilibrium Constant (19.5) G Reaction Parameters at Standard State K E cell Reaction at standardstate conditions < 0 = 0 > 0 > 1 = 1 < 1 > 0 = 0 < 0 spontaneous at equilibrium nonspontaneous E cell K RT E cell = ln K nf EX 14. What is the equilibrium constant for the cell of example 11? EX 15. If E o (Cr 3+ Cr) = V and E o (Zn 2+ Zn) = V what is the equilibrium constant for 2 Cr 3+ (aq) + 3 Zn(s) 2 Cr(s) + 3 Zn 2+ (aq) solubility product, Ksp
11 EX 16. From the following reaction cell where Ecell = V Pt H 2(1 atm) H + (1.00 M) Cl - (l M), Ag + (? M) AgCl(s) Ag(s) determine the value of K sp(agcl). Relevant standard reduction potentials are 2 H + (aq) + 2 e - H 2(g) E o = V Ag + (aq) + e - Ag(s) E o = V EX 17. Determine the value of K sp(agscn) given that AgSCN(s) + e - Ag(s) + SCN - (aq) Ag + (aq) + e - Ag(s) E o = V E o = V
12 Concentration Cells - Q wins! (p. 912) Ecell > 0 as long as the half-cell concentrations are different. The cell is no longer able to do work once the concentrations are equal. Corrosion (19.9) 4 Fe 2+ (aq) + O 2(g) + (4 + 2x) H 2O(l) 2 Fe 2O 3 xh 2O(s) + 8 H + (aq) rust OXIDATION (at anode) Fe(s) Fe 2+ (aq) + 2e - -E o = V Cu(s) Cu 2+ (aq) + 2e - -E o = V Zn(s) Zn 2+ (aq) + 2e - -E o = V cathodic protection: use a sacrificial anode REDUCTION (at cathode) O 2(g) + 4 H + (aq) + 4e - 2H 2O(l) E o = V acidic conditions O 2(g) + 2 H 2O (l) + 4e - 4 OH - (aq) E o = V basic conditions
13 Nerve Transmission (p. 914) A nerve cell (neuron) can be likened to a receiver, transmitter, and transmission line between the two. Dendrites receive im-pulse signals from a neighboring neuron. Transmission of electrical signals within the receiving neuron proceeds from dendrites to synapse along the length of the axon. The signal is due to opening and closing of sodium channels in the axon s membrane, allowing Na + to enter or not enter the cell. Entering Na + causes an increase in charge inside the cell. At rest, the inside of a neuron is slightly negative (~ -70 mv) due to a higher concentration of K + ions inside (concentration gradient balanced by a potential difference across the membrane, Einside - Eoutside which can be calculated by modifying the Nernst equation) E = E o + ( /n) log Q K + Na + inside 20 x y outside x 10 y where n is the charge of the ion. An impulse opens Na + channels. When stimulated past a threshold Na + rushes into the axon, causing a region of positive charge (depolarization) within the axon and a potential of ~30 mv across the membrane. The channels open in one direction along the axon as an opened channel needs a rest period before it can reopen. The region of positive charge causes nearby Na + channels to close. Just after the Na + channels close, K + channels open and K + exits the axon (repolarization). The membrane is brought back to its negative resting potential by Na + /K + pumps in the cell membrane. This process continues as a chain-reaction along the axon. The influx of sodium ions depolarises the axon, and the outflow of potassium ions repolarises it.
ELECTROCHEMISTRY Chapter 14
ELECTROCHEMISTRY Chapter 14 Basic Concepts: Overview of Electrochemical Process at Constant T, P (14-1) ΔG = ΔG o + RT ln Q = w elec (maximum) = qe = ItE (exp) (E intensive parameter, q extensive) = nfe
More informationELECTROCHEMISTRY OXIDATION-REDUCTION
ELECTROCHEMISTRY Electrochemistry involves the relationship between electrical energy and chemical energy. OXIDATION-REDUCTION REACTIONS SPONTANEOUS REACTIONS Can extract electrical energy from these.
More informationChapter 20. Electrochemistry. Chapter 20 Problems. Electrochemistry 7/3/2012. Problems 15, 17, 19, 23, 27, 29, 33, 39, 59
Chemistry, The Central Science, 11th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 20 John D. Bookstaver St. Charles Community College Cottleville, MO Chapter 20 Problems
More informationLecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education
Lecture Presentation Chapter 20 James F. Kirby Quinnipiac University Hamden, CT is the study of the relationships between electricity and chemical reactions. It includes the study of both spontaneous and
More informationOxidation-Reduction Review. Electrochemistry. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions. Sample Problem.
1 Electrochemistry Oxidation-Reduction Review Topics Covered Oxidation-reduction reactions Balancing oxidationreduction equations Voltaic cells Cell EMF Spontaneity of redox reactions Batteries Electrolysis
More informationChapter 18 Electrochemistry. Electrochemical Cells
Chapter 18 Electrochemistry Chapter 18 1 Electrochemical Cells Electrochemical Cells are of two basic types: Galvanic Cells a spontaneous chemical reaction generates an electric current Electrolytic Cells
More informationCHEMISTRY 13 Electrochemistry Supplementary Problems
1. When the redox equation CHEMISTRY 13 Electrochemistry Supplementary Problems MnO 4 (aq) + H + (aq) + H 3 AsO 3 (aq) Mn 2+ (aq) + H 3 AsO 4 (aq) + H 2 O(l) is properly balanced, the coefficients will
More informationLecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education, Inc.
Lecture Presentation Chapter 20 James F. Kirby Quinnipiac University Hamden, CT is the study of the relationships between electricity and chemical reactions. It includes the study of both spontaneous and
More informationChapter 20 Electrochemistry
Chapter 20 Electrochemistry Learning goals and key skills: Identify oxidation, reduction, oxidizing agent, and reducing agent in a chemical equation Complete and balance redox equations using the method
More informationElectrochemistry objectives
Electrochemistry objectives 1) Understand how a voltaic and electrolytic cell work 2) Be able to tell which substance is being oxidized and reduced and where it is occuring the anode or cathode 3) Students
More informationElectrochemistry. A. Na B. Ba C. S D. N E. Al. 2. What is the oxidation state of Xe in XeO 4? A +8 B +6 C +4 D +2 E 0
Electrochemistry 1. Element M reacts with oxygen to from an oxide with the formula MO. When MO is dissolved in water, the resulting solution is basic. Element M is most likely: A. Na B. Ba C. S D. N E.
More informationOxidation (oxidized): the loss of one or more electrons. Reduction (reduced): the gain of one or more electrons
1 of 13 interesting links: Battery Chemistry Tutorial at http://www.powerstream.com/batteryfaq.html Duracell Procell: Battery Chemistry at http://www.duracell.com/procell/chemistries /default.asp I. Oxidation
More informationElectrochemistry. The study of the interchange of chemical and electrical energy.
Electrochemistry The study of the interchange of chemical and electrical energy. Oxidation-reduction (redox) reaction: involves a transfer of electrons from the reducing agent to the oxidizing agent. oxidation:
More informationSection Electrochemistry represents the interconversion of chemical energy and electrical energy.
Chapter 21 Electrochemistry Section 21.1. Electrochemistry represents the interconversion of chemical energy and electrical energy. Electrochemistry involves redox (reduction-oxidation) reactions because
More informationChapter 19: Electrochemistry
Chapter 19: Electrochemistry Overview of the Chapter review oxidation-reduction chemistry basics galvanic cells spontaneous chemical reaction generates a voltage set-up of galvanic cell & identification
More informationLecture 14. Thermodynamics of Galvanic (Voltaic) Cells.
Lecture 14 Thermodynamics of Galvanic (Voltaic) Cells. 51 52 Ballard PEM Fuel Cell. 53 Electrochemistry Alessandro Volta, 1745-1827, Italian scientist and inventor. Luigi Galvani, 1737-1798, Italian scientist
More informationOxidation-Reduction (Redox)
Oxidation-Reduction (Redox) Electrochemistry involves the study of the conversions between chemical and electrical energy. Voltaic (galvanic) cells use chemical reactions to produce an electric current.
More informationChapter 18 problems (with solutions)
Chapter 18 problems (with solutions) 1) Assign oxidation numbers for the following species (for review see section 9.4) a) H2SO3 H = +1 S = +4 O = -2 b) Ca(ClO3)2 Ca = +2 Cl = +5 O = -2 c) C2H4 C = -2
More informationCh 18 Electrochemistry OIL-RIG Reactions
Ch 18 Electrochemistry OIL-RIG Reactions Alessandro Volta s Invention Modified by Dr. Cheng-Yu Lai Daily Electrochemistry Appliactions Electrochemistry: The area of chemistry that examines the transformations
More informationRedox reactions & electrochemistry
Redox reactions & electrochemistry Electrochemistry Electrical energy ; Chemical energy oxidation/reduction = redox reactions Electrochemistry Zn + Cu 2+ º Zn 2+ + Cu Oxidation-reduction reactions always
More information17.1 Redox Chemistry Revisited
Chapter Outline 17.1 Redox Chemistry Revisited 17.2 Electrochemical Cells 17.3 Standard Potentials 17.4 Chemical Energy and Electrical Work 17.5 A Reference Point: The Standard Hydrogen Electrode 17.6
More informationChapter 19: Oxidation - Reduction Reactions
Chapter 19: Oxidation - Reduction Reactions 19-1 Oxidation and Reduction I. Oxidation States A. The oxidation rules (as summarized by Mr. Allan) 1. In compounds, hydrogen has an oxidation # of +1. In compounds,
More informationElectrochemistry Pearson Education, Inc. Mr. Matthew Totaro Legacy High School AP Chemistry
2012 Pearson Education, Inc. Mr. Matthew Totaro Legacy High School AP Chemistry Electricity from Chemistry Many chemical reactions involve the transfer of electrons between atoms or ions electron transfer
More informationOxidation Numbers, ox #
Oxidation Numbers, ox # are or numbers assigned to each or assuming that the are transferred from the electronegative element to the electronegative element. now mimic systems. ox # are written followed
More informationPart One: Introduction. a. Chemical reactions produced by electric current. (electrolysis)
CHAPTER 19: ELECTROCHEMISTRY Part One: Introduction A. Terminology. 1. Electrochemistry deals with: a. Chemical reactions produced by electric current. (electrolysis) b. Production of electric current
More informationElectrochem: It s Got Potential!
Electrochem: It s Got Potential! Presented by: Denise DeMartino Westlake High School, Eanes ISD Pre-AP, AP, and Advanced Placement are registered trademarks of the College Board, which was not involved
More informationCh 20 Electrochemistry: the study of the relationships between electricity and chemical reactions.
Ch 20 Electrochemistry: the study of the relationships between electricity and chemical reactions. In electrochemical reactions, electrons are transferred from one species to another. Learning goals and
More informationOxidation-reduction (redox) reactions
Oxidation-reduction (redox) reactions Reactions in which there are changes in oxidation state (oxidation number) between reactants and products 2 MnO 4- + 10 Br - + 16 H + 2 Mn 2+ + 5 Br 2 + 8 H 2 O One
More informationElectrochemistry. Chapter 18. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Electrochemistry Chapter 18 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Electrochemical processes are oxidation-reduction reactions in which: the energy
More informationChapter 18 Electrochemistry
Chapter 18 Electrochemistry Definition The study of the interchange of chemical and electrical energy in oxidation-reduction (redox) reactions This interchange can occur in both directions: 1. Conversion
More informationGeneral Chemistry I. Dr. PHAN TẠI HUÂN Faculty of Food Science and Technology Nong Lam University
General Chemistry I Dr. PHAN TẠI HUÂN Faculty of Food Science and Technology Nong Lam University Module 7: Oxidation-reduction reactions and transformation of chemical energy Oxidation-reduction reactions
More informationChemistry 102 Chapter 19 OXIDATION-REDUCTION REACTIONS
OXIDATION-REDUCTION REACTIONS Some of the most important reaction in chemistry are oxidation-reduction (redox) reactions. In these reactions, electrons transfer from one reactant to the other. The rusting
More informationElectrochemical Reactions
1 of 20 4/11/2016 1:00 PM Electrochemical Reactions Electrochemical Reactions Electrical Work From Spontaneous Oxidation- Reduction Reactions Predicting Spontaneous Redox Reactions from the Sign of E Line
More informationZn+2 (aq) + Cu (s) Oxidation: An atom, ion, or molecule releases electrons and is oxidized. The oxidation number of the atom oxidized increases.
Oxidation-Reduction Page 1 The transfer of an electron from one compound to another results in the oxidation of the electron donor and the reduction of the electron acceptor. Loss of electrons (oxidation)
More informationChem 321 Lecture 16 - Potentiometry 10/22/13
Student Learning Objectives Chem 321 Lecture 16 - Potentiometry 10/22/13 In lab you will use an ion-selective electrode to determine the amount of fluoride in an unknown solution. In this approach, as
More information(for tutoring, homework help, or help with online classes)
www.tutor-homework.com (for tutoring, homework help, or help with online classes) 1. chem10b 20.4-3 In a voltaic cell electrons flow from the anode to the cathode. Value 2. chem10b 20.1-35 How many grams
More informationCHEM J-14 June 2014
CHEM1101 2014-J-14 June 2014 An electrochemical cell consists of an Fe 2+ /Fe half cell with unknown [Fe 2+ ] and a Sn 2+ /Sn half-cell with [Sn 2+ ] = 1.10 M. The electromotive force (electrical potential)
More informationChapter 19 - Electrochemistry. the branch of chemistry that examines the transformations between chemical and electrical energy
Chapter 19 - Electrochemistry the branch of chemistry that examines the transformations between chemical and electrical energy 19.1 Redox Chemistry Revisited A Spontaneous Redox Reaction Znº(s) + Cu 2+
More informationCHEMISTRY - CLUTCH CH.18 - ELECTROCHEMISTRY.
!! www.clutchprep.com CONCEPT: OXIDATION-REDUCTION REACTIONS Chemists use some important terminology to describe the movement of electrons. In reactions we have the movement of electrons from one reactant
More informationOxidation number. The charge the atom would have in a molecule (or an ionic compound) if electrons were completely transferred.
Oxidation number The charge the atom would have in a molecule (or an ionic compound) if electrons were completely transferred. 1. Free elements (uncombined state) have an oxidation number of zero. Na,
More informationAssigning Oxidation Numbers:
Assigning Oxidation Numbers: 1. Oxidation number of a free element or diatomic molecule is zero. Ex: Na(s), Cu(s), H 2 (g), F 2 (g) 2. In most cases the oxidation number of hydrogen is +1, oxygen is -2,
More informationChpt 20: Electrochemistry
Cell Potential and Free Energy When both reactants and products are in their standard states, and under constant pressure and temperature conditions where DG o = nfe o DG o is the standard free energy
More informationElectrochemistry 1 1
Electrochemistry 1 1 Half-Reactions 1. Balancing Oxidation Reduction Reactions in Acidic and Basic Solutions Voltaic Cells 2. Construction of Voltaic Cells 3. Notation for Voltaic Cells 4. Cell Potential
More informationRedox and Electrochemistry
Redox and Electrochemistry 1 Electrochemistry in Action! 2 Rules for Assigning Oxidation Numbers The oxidation number of any uncombined element is 0. The oxidation number of a monatomic ion equals the
More informationElectrode Potentials and Their Measurement
Electrochemistry Electrode Potentials and Their Measurement Cu(s) + 2Ag + (aq) Cu(s) + Zn 2+ (aq) Cu 2+ (aq) + 2 Ag(s) No reaction Zn(s) + Cu 2+ (aq) Cu(s) + Zn 2+ (aq) In this reaction: Zn (s) g Zn 2+
More informationChemistry: The Central Science. Chapter 20: Electrochemistry
Chemistry: The Central Science Chapter 20: Electrochemistry Redox reaction power batteries Electrochemistry is the study of the relationships between electricity and chemical reactions o It includes the
More informationChapter 17. Electrochemistry
Chapter 17 Electrochemistry Contents Galvanic cells Standard reduction potentials Cell potential, electrical work, and free energy Dependence of cell potential on concentration Batteries Corrosion Electrolysis
More informationDr. Anand Gupta
By Dr Anand Gupta Mr. Mahesh Kapil Dr. Anand Gupta 09356511518 09888711209 anandu71@yahoo.com mkapil_foru@yahoo.com Electrochemistry Electrolysis Electric energy Chemical energy Galvanic cell 2 Electrochemistry
More informationChapter Nineteen. Electrochemistry
Chapter Nineteen Electrochemistry 1 Electrochemistry The study of chemical reactions through electrical circuits. Monitor redox reactions by controlling electron transfer REDOX: Shorthand for REDuction-OXidation
More informationChapter 20. Electrochemistry
Chemistry, The Central Science, 10th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 20 John D. Bookstaver St. Charles Community College St. Peters, MO 2006, Prentice Hall,
More informationIntroduction Oxidation/reduction reactions involve the exchange of an electron between chemical species.
Introduction Oxidation/reduction reactions involve the exchange of an electron between chemical species. The species that loses the electron is oxidized. The species that gains the electron is reduced.
More informationElectrochemistry. Review oxidation reactions and how to assign oxidation numbers (Ch 4 Chemical Reactions).
Electrochemistry Oxidation-Reduction: Review oxidation reactions and how to assign oxidation numbers (Ch 4 Chemical Reactions). Half Reactions Method for Balancing Redox Equations: Acidic solutions: 1.
More informationChapter 18: Electrochemistry
Chapter 18: Electrochemistry Oxidation States An oxidation-reduction reaction, or redox reaction, is one in which electrons are transferred. 2Na + Cl 2 2NaCl Each sodium atom is losing one electron to
More informationElectrochemistry (Galvanic and Electrolytic Cells) Exchange of energy in chemical cells
Electrochemistry (Galvanic and Electrolytic Cells) Exchange of energy in chemical cells Oxidation loss of electrons (oxidation number increases) OIL RIG Reduction gain of electrons (oxidation number decreases)
More informationChapter 20 Electrochemistry
Chapter 20 Electrochemistry 20.1 Oxidation States and Oxidation-Reduction Reactions An oxidation occurs when an atom or ion loses electrons. A reduction occurs when an atom or ion gains electrons. One
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
A.P. Chemistry Practice Test - Ch. 17: Electochemistry MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The gain of electrons by an element is called.
More informationHomework 11. Electrochemical Potential, Free Energy, and Applications
HW11 Electrochemical Poten!al, Free Energy, and Applica!ons Homework 11 Electrochemical Potential, Free Energy, and Applications Question 1 What is the E for Zn(s) Zn (aq) Ce (aq) Ce (aq) + cell + 4+ 3+
More informationELECTROCHEMISTRY. Oxidation/Reduction
ELECTROCHEMISTRY Electrochemistry involves the relationship between electrical energy and chemical energy. OXIDATION-REDUCTION REACTIONS SPONTANEOUS REACTIONS Examples: voltaic cells, batteries. NON-SPONTANEOUS
More informationChapter 20. Electrochemistry Recommendation: Review Sec. 4.4 (oxidation-reduction reactions) in your textbook
Chapter 20. Electrochemistry Recommendation: Review Sec. 4.4 (oxidation-reduction reactions) in your textbook 20.1 Oxidation-Reduction Reactions Oxidation-reduction reactions = chemical reactions in which
More informationChapter 18. Electrochemistry
Chapter 18 Electrochemistry Section 17.1 Spontaneous Processes and Entropy Section 17.1 http://www.bozemanscience.com/ap-chemistry/ Spontaneous Processes and Entropy Section 17.1 Spontaneous Processes
More informationChapter 20. Electrochemistry
Chapter 20. Electrochemistry 20.1 Oxidation-Reduction Reactions Oxidation-reduction reactions = chemical reactions in which the oxidation state of one or more substance changes (redox reactions). Recall:
More informationGuide to Chapter 18. Electrochemistry
Guide to Chapter 18. Electrochemistry We will spend three lecture days on this chapter. During the first class meeting we will review oxidation and reduction. We will introduce balancing redox equations
More informationChapter 20. Electrochemistry
Chapter 20. Electrochemistry 20.1 OxidationReduction Reactions Oxidationreduction reactions = chemical reactions in which the oxidation state of one or more substance changes (redox reactions). Recall:
More informationCHEM N-12 November In the electrolytic production of Al, what mass of Al can be deposited in 2.00 hours by a current of 1.8 A?
CHEM161 014-N-1 November 014 In the electrolytic production of Al, what mass of Al can be deposited in.00 hours by a current of 1.8 A? What products would you expect at the anode and the cathode on electrolysis
More informationLecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education
Lecture Presentation Chapter 20 James F. Kirby Quinnipiac University Hamden, CT is the study of the relationships between electricity and chemical reactions. It includes the study of both spontaneous and
More informationReducing Agent = a substance which "gives" electrons to another substance causing that substance to be reduced; a reducing agent is itself oxidized.
Oxidation = a loss of electrons; an element which loses electrons is said to be oxidized. Reduction = a gain of electrons; an element which gains electrons is said to be reduced. Oxidizing Agent = a substance
More informationLecture Presentation. Chapter 18. Electrochemistry. Sherril Soman Grand Valley State University Pearson Education, Inc.
Lecture Presentation Chapter 18 Electrochemistry Sherril Soman Grand Valley State University Harnessing the Power in Nature The goal of scientific research is to understand nature. Once we understand the
More informationElectrochemical Cells
Electrochemistry Electrochemical Cells The Voltaic Cell Electrochemical Cell = device that generates electricity through redox rxns 1 Voltaic (Galvanic) Cell An electrochemical cell that produces an electrical
More informationElectrochemistry Pulling the Plug on the Power Grid
Electrochemistry 18.1 Pulling the Plug on the Power Grid 18.3 Voltaic (or Galvanic) Cells: Generating Electricity from Spontaneous Chemical Reactions 18.4 Standard Electrode Potentials 18.7 Batteries:
More informationElectrochemistry. Remember from CHM151 G E R L E O 6/24/2014. A redox reaction in one in which electrons are transferred.
Electrochemistry Remember from CHM151 A redox reaction in one in which electrons are transferred Reduction Oxidation For example: L E O ose lectrons xidation G E R ain lectrons eduction We can determine
More informationGeneral Chemistry 1412 Spring 2008 Instructor: Dr. Shawn Amorde Website:
General Chemistry 1412 Spring 2008 Instructor: Dr. Shawn Amorde Website: www.austincc.edu/samorde Email: samorde@austincc.edu Lecture Notes Chapter 21 (21.1-21.25) Suggested Problems () Outline 1. Introduction
More informationElectrochemical System
Electrochemical System Topic Outcomes Week Topic Topic Outcomes 8-10 Electrochemical systems It is expected that students are able to: Electrochemical system and its thermodynamics Chemical reactions in
More informationChapter 18. Electrochemistry
Chapter 18 Electrochemistry Oxidation-Reduction Reactions Review of Terms Oxidation-reduction (redox) reactions always involve a transfer of electrons from one species to another. Oxidation number - the
More informationCHAPTER 17: ELECTROCHEMISTRY. Big Idea 3
CHAPTER 17: ELECTROCHEMISTRY Big Idea 3 Electrochemistry Conversion of chemical to electrical energy (discharge). And its reverse (electrolysis). Both subject to entropic caution: Convert reversibly to
More informationAP Questions: Electrochemistry
AP Questions: Electrochemistry I 2 + 2 S 2O 2-3 2 I - + S 4O 2-6 How many moles of I 2 was produced during the electrolysis? The hydrogen gas produced at the cathode during the electrolysis was collected
More information1.In which of the following is the oxidation number of the underlined element given incorrectly? oxidation number
General Chemistry II Exam 4 Practice Problems 1 1.In which of the following is the oxidation number of the underlined element given incorrectly? oxidation number a. K 2 Cr 2 O 7 +6 b. NaAl(OH) 4 +3 c.
More informationIntroduction to electrochemistry
Introduction to electrochemistry Oxidation reduction reactions involve energy changes. Because these reactions involve electronic transfer, the net release or net absorption of energy can occur in the
More informationREDUCTION - OXIDATION TITRATION REDOX TITRATION
References REDUCTION OXIDATION TITRATION REDOX TITRATION 1 Fundamentals of analytical chemistry, Skoog. 2 Analytical chemistry, Gary D. Christian. الكيمياء التحليلية الجامعية تأليف د.هادي حسن جاسم 3 Oxidation
More informationName AP CHEM / / Collected Essays Chapter 17
Name AP CHEM / / Collected Essays Chapter 17 1980 - #2 M(s) + Cu 2+ (aq) M 2+ (aq) + Cu(s) For the reaction above, E = 0.740 volt at 25 C. (a) Determine the standard electrode potential for the reaction
More informationRedox Reactions and Electrochemistry
Redox Reactions and Electrochemistry Problem Set Chapter 5: 2126, Chapter 21: 1517, 32, 34, 43, 53, 72, 74 R Oxidation/Reduction & Electrochemistry Oxidation a reaction in which a substance gains oxygen
More informationCHEM J-14 June 2014
CHEM1101 2014-J-14 June 2014 An electrochemical cell consists of an Fe 2+ /Fe half cell with unknown [Fe 2+ ] and a Sn 2+ /Sn half-cell with [Sn 2+ ] = 1.10 M. The electromotive force (electrical potential)
More informationSHOCK TO THE SYSTEM! ELECTROCHEMISTRY
SHOCK TO THE SYSTEM! ELECTROCHEMISTRY REVIEW I. Re: Balancing Redox Reactions. A. Every redox reaction requires a substance to be... 1. oxidized (loses electrons). a.k.a. reducing agent 2. reduced (gains
More informationElectrochemistry. 1. Determine the oxidation states of each element in the following compounds. (Reference: Ex. 4:16) a. N 2 N: b.
Name: Electrochemistry Two of the most common types of chemical reactions are acid-base reactions in which protons are transferred between two reactants and oxidation-reduction reactions in which electrons
More informationReview: Balancing Redox Reactions. Review: Balancing Redox Reactions
Review: Balancing Redox Reactions Determine which species is oxidized and which species is reduced Oxidation corresponds to an increase in the oxidation number of an element Reduction corresponds to a
More information25. A typical galvanic cell diagram is:
Unit VI(6)-III: Electrochemistry Chapter 17 Assigned Problems Answers Exercises Galvanic Cells, Cell Potentials, Standard Reduction Potentials, and Free Energy 25. A typical galvanic cell diagram is: The
More informationReview. Chapter 17 Electrochemistry. Outline. Voltaic Cells. Electrochemistry. Mnemonic
Review William L Masterton Cecile N. Hurley Edward J. Neth cengage.com/chemistry/masterton Chapter 17 Electrochemistry Oxidation Loss of electrons Occurs at electrode called the anode Reduction Gain of
More informationIntroduction. can be rewritten as follows: Oxidation reaction. H2 2H + +2e. Reduction reaction: F2+2e 2F. Overall Reaction H2+F2 2H + +2F
Electrochemistry is the study of chemical processes that cause electrons to move. This movement of electrons is called electricity, which can be generated by movements of electrons from one element to
More informationOxidation & Reduction (Redox) Notes
Oxidation & Reduction (Redox) Notes Chemical Activity (or Chemical Reactivity) is the measure of the reactivity of elements. If an element has high activity, then it means that the element is willing to
More informationStandard reduction potentials are established by comparison to the potential of which half reaction?
HW10 Electrochemical Poten al, Free Energy, and Applica ons This is a preview of the draft version of the quiz Started: Nov 8 at 5:51pm Quiz Instruc ons Question 1 What is the E for cell + 4+ 3+ Zn(s)
More informationAP Chemistry: Electrochemistry Multiple Choice Answers
AP Chemistry: Electrochemistry Multiple Choice Answers 14. Questions 14-17 The spontaneous reaction that occurs when the cell in the picture operates is as follows: 2Ag + + Cd (s) à 2 Ag (s) + Cd 2+ (A)
More informationUnit 12 Redox and Electrochemistry
Unit 12 Redox and Electrochemistry Review of Terminology for Redox Reactions OXIDATION loss of electron(s) by a species; increase in oxidation number. REDUCTION gain of electron(s); decrease in oxidation
More informationElectrochemistry. Outline
Electrochemistry Outline 1. Oxidation Numbers 2. Voltaic Cells 3. Calculating emf or Standard Cell Potential using Half-Reactions 4. Relationships to Thermo, Equilibrium, and Q 5. Stoichiometry 6. Balancing
More informationA voltaic cell using the following reaction is in operation: 2 Ag + (lm) + Cd(s) 2 Ag(s) + Cd 2+ (l M)
0. Cu (s) + 2Ag + Cu 2+ + 2Ag (s) If the equilibrium constant for the reaction above is 3.7x10 15, which of the following correctly describes the standard voltage, E o and the standard free energy change,
More informationLecture #15. Chapter 18 - Electrochemistry
Lecture #15 Chapter 18 - Electrochemistry Chapter 18 - Electrochemistry the branch of chemistry that examines the transformations between chemical and electrical energy Redox Chemistry Revisited A Spontaneous
More informationCh 11 Practice Problems
Ch 11 Practice Problems 1. How many electrons are transferred in the following reaction? 2Cr 2O 7 2- + 14H + + 6Cl 2Cr 3+ + 3Cl 2 + 7H 2O A) 2 B) 4 C) 6 D) 8 2. Which metal, Al or Ni, could reduce Zn 2+
More information2. Using Half Cell Potentials and Latimer Diagrams. 100 measured half cell potentials generate 10,000 full reactions
Electrochemistry 1. Balancing Redox Reactions 2. Using Half Cell Potentials and Latimer Diagrams 100 measured half cell potentials generate 10,000 full reactions 3. E as a Thermodynamic state function
More informationElectrochem 1 Electrochemistry Some Key Topics Conduction metallic electrolytic Electrolysis effect and stoichiometry Galvanic cell Electrolytic cell Electromotive Force (potential in volts) Electrode
More informationElectrochemistry. (Hebden Unit 5 ) Electrochemistry Hebden Unit 5
(Hebden Unit 5 ) is the study of the interchange of chemical energy and electrical energy. 2 1 We will cover the following topics: Review oxidation states and assigning oxidation numbers Redox Half-reactions
More informationChemistry 1011 TOPIC TEXT REFERENCE. Electrochemistry. Masterton and Hurley Chapter 18. Chemistry 1011 Slot 5 1
Chemistry 1011 TOPIC Electrochemistry TEXT REFERENCE Masterton and Hurley Chapter 18 Chemistry 1011 Slot 5 1 18.5 Electrolytic Cells YOU ARE EXPECTED TO BE ABLE TO: Construct a labelled diagram to show
More informationRedox Reactions and Electrochemistry
Redox Reactions and Electrochemistry Redox Reactions and Electrochemistry Redox Reactions (19.1) Galvanic Cells (19.2) Standard Reduction Potentials (19.3) Thermodynamics of Redox Reactions (19.4) The
More information