Exercise 4 Oxidation-reduction (redox) reaction oxidimetry. Theoretical part
|
|
- Joshua Knight
- 5 years ago
- Views:
Transcription
1 Exercise 4 Oxidation-reduction (redox) reaction oxidimetry. Theoretical part In oxidation-reduction (or redox) reactions, the key chemical event is the net movement of electrons from one reactant to the other. Redox reactions constitute some of the most important of all chemical processes, including the formation of a compound from its elements, all combustion reactions, the reactions in batteries that generate electricity, and the production of biochemical energy. 1. Redox terminology Oxidation is the loss of electrons, reduction is the gain of electrons. During the formation of magnesium oxide (for example) Mg undergoes oxidation (electron loss) and O 2 undergoes reduction (electron gain). The loss and gain are simultaneous, but we can imagine them occurring in separate steps: Oxidation: Mg Mg e - (electron lost by Mg) Reduction: ½ O 2 O 2- (electrons gained by O 2 ) Since O 2 gained the electrons that Mg lost when Mg was oxidized, we say that O 2 oxidized Mg, or that O 2 is the oxidizing agent, the species doing the oxidizing. Similarly, since Mg gave up the electrons that O 2 gained when O 2 was reduced, Mg reduced O 2. Mg is the reducing agent, the species doing the reducing. It is extremely important to realize that the oxidation and the reduction occur simultaneously. There is no such chemical change as an oxidation reaction or a reduction reaction; only an oxidation-reduction reaction can occur. e - X Transfer or shift of electrons Y X loses electron (s) X is oxidized X is the reducing agent X increases in oxidation number Y gains electron (s) Y is reduced Y is the oxidizing agent Y decreases in oxidation number 1
2 Each atoms is assigned an oxidation number (O.N., or oxidation state), which is determined by the set of rules. General rules 1. For an atom in its elemental form (Na, O 2, Cl 2, and so forth): O.N. = 0 2. For a monatomic ion: O.N. = ion charge 3. The sum of O.N. values for the atoms in a compound equals zero. The sum of O.N. values for the atoms in a polyatomic ion equals the ion charge. Rules for specific atoms or periodic table groups 1. For Group 1A: O.N. = +1 in all compounds 2. For Group 2A: O.N. = +2 in all compounds 3. For hydrogen: O.N. = +1 in combination with nonmetals O.N. = -1 in combination with metals and boron 4. For fluorine: O.N. = -1 in all compounds 5. For oxygen: O.N. = -1 in peroxides O.N. = -2 in all other compounds 9exept with F) 6. For Group 7A: O.N. = -1 in combination with metals, nonmetals (except O), and other halogens lower in the group Balancing redox reactions Since oxidation and reduction occur simultaneously, the transferred electrons are never free and must be accounted for in the overall process. Therefore, the total number of electrons lost by the oxidized reactant must equal the total number of electrons gained by the reduced reactant. By keeping track of the changes in oxidation numbers and the number of electrons transferred, we can balance redox reactions. Two methods used to balance redox reactions are the oxidation number method and the half-reaction method. The oxidation number method. The oxidation number method consists of five steps that use the changes in oxidation numbers to generate balancing coefficients. Step 1. Assign oxidation numbers to all elements in the equation Cu + HNO 3 Cu(NO 3 ) 2 + NO 2 + H 2 O Step 2. From the changes in oxidation numbers, identify the oxidized and reduced species. 2
3 Step 3. Compute the number of electrons lost in the oxidation and gained in the reduction from the oxidation number changes. Draw tie-lines between these atoms to show electron changes. -2e - Cu + HNO 3 Cu(NO 3 ) 2 + NO 2 + H 2 O +1e - Step 4. Multiply one or both of these numbers by appropriate factors to make the electrons lost equal the electrons gained, and use the factors as balancing coefficients. Cu + 2HNO 3 Cu(NO 3 ) 2 + 2NO 2 + H 2 O Step 5. Complete the balancing by inspection, adding states of matter. Cu + 4HNO 3 Cu(NO 3 ) 2 + 2NO 2 + 2H 2 O The half-reaction method. The other method for balancing redox reactions is called the halfreaction method because the overall oxidation-reduction process is viewed as the sum of oxidation half-reaction and a reduction half-reaction, each of which involves either the loss or the gain of electrons. Consider the reaction between zinc metal and hydrochloric acid: Zn + HCl ZnCl 2 + H 2 We can break up this equation into two half-reactions. Zn Zn e - [oxidation half-reaction] e - + H + ½ H 2 [reduction half-reaction] In each half-reaction, moles of atoms and amount of charge are balanced. To obtain integer coefficients and to make the number of electrons lost equal the number gained, we double the reduction half-reaction: Zn Zn e - [oxidation half-reaction] 3
4 2e - + 2H + H 2 [reduction half-reaction doubled] Next, we add the half-reactions together, and the electrons cancel: Zn + 2H + Zn 2+ + H 2 Adding the appropriate number of spectator gives the balanced total equation: Zn + 2HCl ZnCl 2 + H 2 Voltaic Cells. Electrochemistry is the study of chemical reactions by use of electrical circuits. This is a natural way to investigate oxidation/reduction reactions since there is an electron transfer occurring. By forcing the transferred electrons to move through a wire, we can measure reaction progress (kinetics), composition (equilibrium constants), energy changes (thermodynamics), and add or subtract energy from the system. A typical electrochemical cell: The oxidation and reduction half reactions are physically separated and connected by an electrical circuit. The electrical circuit is completed by using two different types of connections. The wire: this is the path that electrons flow from the oxidation to the reduction. The salt bridge: this completes the electrical circuit but does not allow electron flow. Rather, the charge is carried by ions (cations or anions). The salt bridge also prevents the two reacting solutions from mixing. The electrode where oxidation occurs is called the anode. 4
5 The electrode where reduction occurs is called the cathode. If the net oxidation/reduction reaction is spontaneous, the cell is called a voltaic cell. Useful work can be done by voltaic cells (these are batteries). If the net oxidation/reduction reaction is nonspontaneous, the cell is called an electrolytic cell. Energy must be supplied to an electrolytic cell in order to drive the oxidation/reduction reaction. Shorthand notation used to describe electrochemical cells: anode reaction cathode reaction The double bars ( ) represent the salt bridge The essential components of each half reaction are described and each piece of information is separated by a single bar ( ). This may include the nature of the electrode, phase information, concentrations or partial pressures, or temperature if the cell is not at standard conditions. Examples Write the half reactions and net reaction for the cell Mg(s) Mg 2+ (aq) Fe 3+ (aq) Fe(s) Anode (oxidation) reaction: Mg(s) Mg 2+ (aq) + 2e The solid magnesium serves as a physical electrode. Cathode (reduction) reaction: Fe 3+ (aq) + 3e Fe(s) The solid iron serves as a physical electrode. Net reaction: 3Mg(s) + 2Fe 3+ (aq) 3Mg 2+ (aq) + 2Fe(s) 5
6 Write the half reactions and net reaction for the cell Al(s) Al 3+ (aq) Hg 2+ (aq) Hg(l) Pt(s) Anode (oxidation) reaction: Al(s) Al 3+ (aq) + 3e The solid aluminum serves as the physical electrode. Cathode (reduction) reaction: Hg 2+ (aq) + 2e Hg(l) The solid platinum serves as the physical electrode. Net reaction: 2Al(s) + 3Hg 2+ (aq) 2Al 3+ (aq) + 3Hg(l) Voltaic cells are used to convert chemical energy to electrical energy that can be used to produce useful work Calculation of the Cell Potential of Standard Voltaic Cells: Whenever two standard half-cells are joined to create a voltaic cell as in figure 1, the one with the more negative E o will function as the anode since it is the metal that is most easily oxidized. The value for the standard potential of the cell, E o cell, is the difference between the standard potential of the cathode and anode: E o cell = E o cathode - E o anode The use of standard reduction potentials to predict the potential of the voltaic cell is illustrated below. 6
7 Reduction Reactions E o Zn 2+ (aq) + 2 e Zn (s) Cu 2+ (aq) + 2 e Cu (s) (more negative potential, therefore the anode) (more positive potential, therefore the cathode) Cathode: Cu 2+ (aq) + 2 e Cu (s) Anode: Zn (s) Zn 2+ (aq) + 2 e E o cathode = V Cell Reaction: Cu 2+ (aq) + Zn (s) Zn 2+ (aq) + Cu (s) - E o anode = -(-0.76 V) E o cell = 1.10 V Calculation of the Cell Potential of a Voltaic Cell NOT at Standard Conditions: If the potential that is measured is not a standard cell, then the Nernst equation can be used to calculate the standard cell potential. 7
8 Nernst Equation Where n = number of electrons transferred in the cell reaction E cell = E o cell n log Q Q c = Reaction quotient E o = standard cell potential (1 M solutions at 298K and 1 atm) E = Cell potential at nonstandard conditions (both potentials are measured in volts) Sample calculation of the standard cell potential for a voltaic cell made of a Sn electrode in 0.10 M Sn 2+ in one half-cell and Al in Al M in the other. 8
9 Reduction Reactions E o Sn 2+ (aq) + 2 e Sn (s) Al 3+ (aq) + 3 e Al (s) V (more positive potential, therefore the cathode) V(more negative potential, therefore the anode) Cathode: (Sn 2+ (aq) + 2 e Sn (s) ) x 3 Anode: (Al (s) Al 3+ (aq) + 3 e ) x 2 E o cathode = V Cell Reaction: 3Sn 2+ (aq) + 2Al (s) 2Al 3+ (aq) + 3Sn (s) - E o anode = -(-1.66 V) E o cell = 1.52 V E cell = E o cell n log Q = [Al [Sn ] ] V - log [0.10] = 1 52V - log 6 [0.10]. 3 2 = 1.52V V E cell = 1.51 V (nearly the same as the standard cell potential!) Redox Titrations Just as a base is used to determine the concentration of an acid (or vice versa) in an acid-base titration, as known concentration of oxidizing agent can be used to determine the unknown concentration of a reducing agent (or vice versa) in redox titration. This indispensable 9
10 analytical tool is used in a wide range of situations, including measuring the iron content in drinking water, the calcium in blood and the vitamin C content in fruits and vegetable. A common oxidizing agent in redox titrations is the permanganate ion, MnO 4-. Because it is strongly colored, the ion also serves as an indicator for monitoring the reaction In the following example, MnO 4 is used to determine the concentration of oxalate ion, C 2 O As long as C 2 O 4 is present, the deep purple MnO 4 is reduced to the very faint pink (nearly colorless) Mn ion. As soon as all the available C 2 O 4 ions have been oxidized to CO 2, the - next drop of MnO 4 turns the solution light purple. This color change indicates the point at 2- which the total number of electrons lost by the oxidized species (C 2 O 4 ) equals the total number of electrons gained by the reduced species (MnO 4- ). We calculate the concentration of 2- - the C 2 O 4 solution from its known volume, the known concentration and volume of the MnO 4 solution MnO 4 - (aq) + 5C 2 O 4 2- (aq) + 16H + (aq) 2Mn 2+ (aq) + 10CO 2(g) + 8H 2 O (l) Experimental 1. Determination of Fe 2+ Reaction: 2+ MnO 4 + 5Fe H + Mn Fe H 2 O Procedure: Complete the tested solution with distilled water up to 100mL in given flask. Mix well and transfer 10mL of the tested solution to the beaker (100mL) using a pipette, next add 10mL 15% H 2 SO. Stir all precisely and titrate with 0.02 M KmnO 4 solution until the mixture turns into faint pink. Record the amount of ml of KmnO 4. Calculate the mass of Fe 2+ (in terms of mg) m = V (KMnO 4 ) C (KMnO 4 ) Determination of K 2 Cr 2 O 7 using iodometric method Reactions: 10
11 K 2 Cr 2 O 7 + 6KJ + 7H 2 SO 4 4 K 2 SO 4 + Cr 2 (SO 4 ) 3 + 3J 2 + 7H 2 O Received iodine is titrated according to the reaction: J Na 2 S 2 O 3 2NaJ + Na 2 S 4 O 6 Summation: 2-2- Cr 2 O 7 3J 2 6S 2 O 3 Procedure: Complete the tested solution using distilled water to 100mL in measured flask. Mix well and transfer 10mL of the tested solution to the beaker (100mL) using a pipette and add small amount of KI and 10mL 15% H 2 SO. Stir all precisely. Cover the mixture with glass and leave for 5 minutes. After this time, titrate with 0.1 M Na 2 S 2 O 3 to observe brown-yellow color, add the starch solution and titrate until the blue color disappears (at the end-point solution should be colourless or faint blue). Record the amount of ml of Na 2 S 2 O 3. Calculate the mass of K 2 Cr 2 O 7 (in terms of mg) m = V (Na 2 S 2 O 3 ) C (Na 2 S 2 O 3 )
Oxidation & 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 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 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 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 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 informationELECTROCHEMISTRY. Electrons are transferred from Al to Cu 2+. We can re write this equation as two separate half reactions:
ELECTROCHEMISTRY A. INTRODUCTION 1. Electrochemistry is the branch of chemistry which is concerned with the conversion of chemical energy to electrical energy, and vice versa. Electrochemical reactions
More informationUnit 8: Redox and Electrochemistry
May 20, 2014 Unit 8: Redox and Electrochemistry http://www.firefly.org/firefly-pictures.html Oxidation Number numbers assigned to atoms that allow us to keep track of electrons. Rule #1: Oxidation number
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 informationOxidation numbers are charges on each atom. Oxidation-Reduction. Oxidation Numbers. Electrochemical Reactions. Oxidation and Reduction
Oxidation-Reduction Oxidation numbers are charges on each atom. 1 2 Electrochemical Reactions Oxidation Numbers In electrochemical reactions, electrons are transferred from one species to another. In order
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 informationINTRODUCTORY CHEMISTRY Concepts and Critical Thinking
INTRODUCTORY CHEMISTRY Concepts and Critical Thinking Sixth Edition by Charles H. Corwin Oxidation and Reduction by Christopher Hamaker 1 Oxidation Reduction Reactions Oxidation reduction reactions are
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 informationIntroduction to Electrochemical reactions. Schweitzer
Introduction to Electrochemical reactions Schweitzer Electrochemistry Create and or store electricity chemically. Use electricity to drive a reaction that normally would not run. Plating metal onto a metal
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 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 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 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 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 informationHonors Chemistry Mrs. Agostine. Chapter 19: Oxidation- Reduction Reactions
Honors Chemistry Mrs. Agostine Chapter 19: Oxidation- Reduction Reactions Let s Review In chapter 4, you learned how atoms rearrange to form new substances Now, you will look at how electrons rearrange
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 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 informationPractice Exam Topic 9: Oxidation & Reduction
Name Practice Exam Topic 9: Oxidation & Reduction 1. What are the oxidation numbers of the elements in sulfuric acid, H 2 SO 4? Hydrogen Sulfur Oxygen A. +1 +6 2 B. +1 +4 2 C. +2 +1 +4 D. +2 +6 8 2. Consider
More information9.1 Introduction to Oxidation and Reduction
9.1 Introduction to Oxidation and Reduction 9.1.1 - Define oxidation and reduction in terms of electron loss and gain Oxidation The loss of electrons from a substance. This may happen through the gain
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 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 5 REVIEW. C. CO 2 D. Fe 2 O 3. A. Fe B. CO
CHAPTER 5 REVIEW 1. The following represents the process used to produce iron from iron III oxide: Fe 2 O 3 + 3CO 2Fe + 3CO 2 What is the reducing agent in this process? A. Fe B. CO C. CO 2 D. Fe 2 O 3
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 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 informationChapter 20. Electrochemistry
Chapter 20. Electrochemistry Sample Exercise 20.1 (p. 845) The nickelcadmium (nicad) battery, a rechargeable dry cell used in batteryoperated devices, uses the following redox reaction to generate electricity:
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 informationSCHOOL YEAR CH- 19 OXIDATION-REDUCTION REACTIONS SUBJECT: CHEMISTRY GRADE: 12
SCHOOL YEAR 2017-18 NAME: CH- 19 OXIDATION-REDUCTION REACTIONS SUBJECT: CHEMISTRY GRADE: 12 TEST A Choose the best answer from the options that follow each question. 1. During oxidation, one or more electrons
More informationELECTROCHEMICAL CELLS
ELECTROCHEMICAL CELLS Electrochemistry 1. Redox reactions involve the transfer of electrons from one reactant to another 2. Electric current is a flow of electrons in a circuit Many reduction-oxidation
More informationOXIDATION-REDUCTIONS REACTIONS. Chapter 19 (From next years new book)
OXIDATION-REDUCTIONS REACTIONS Chapter 19 (From next years new book) ELECTROCHEMICAL REACTIONS: What are electrochemical reactions? Electrons are transferred from one species to another ACTIVATING PRIOR
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 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. Oxidation-Reduction. Cu (s) + 2AgNO 3(aq) 2Ag (s) + Cu(NO 3 ) 2(aq) pale blue solution. colorless solution. silver crystals.
Chapter 17 Oxidation-Reduction Cu (s) + 2AgNO 3(aq) 2Ag (s) + Cu(NO 3 ) 2(aq) copper wire colorless solution silver crystals pale blue solution Introduction to General, Organic, and Biochemistry 10e John
More informationChapter Objectives. Chapter 13 Electrochemistry. Corrosion. Chapter Objectives. Corrosion. Corrosion
Chapter Objectives Larry Brown Tom Holme Describe at least three types of corrosion and identify chemical reactions responsible for corrosion. www.cengage.com/chemistry/brown Chapter 13 Electrochemistry
More informationChapter 19: Redox & Electrochemistry
Chapter 19: Redox & Electrochemistry 1. Oxidation-Reduction Reactions Definitions Oxidation - refers to the of electrons by a molecule, atom or ion Reduction - refers to the of electrons by an molecule,
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 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 informationChapter 20 Electrochemistry
Chapter 20 Electrochemistry Electrochemical Cell Consists of electrodes which dip into an electrolyte & in which a chem. rxn. uses or generates an electric current Voltaic (Galvanic) Cell Spont. rxn. -
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 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 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 informationReactions in aqueous solutions Redox reactions
Reactions in aqueous solutions Redox reactions Redox reactions In precipitation reactions, cations and anions come together to form an insoluble ionic compound. In neutralization reactions, H + ions and
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 informationOxidation-Reduction Reactions and Introduction to Electrochemistry
ADVANCED PLACEMENT CHEMISTRY Oxidation-Reduction Reactions and Introduction to Electrochemistry Students will be able to: identify oxidation and reduction of chemical species; identify oxidants and reductants
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 informationSection A: Summary Notes
ELECTROCHEMICAL CELLS 25 AUGUST 2015 Section A: Summary Notes Important definitions: Oxidation: the loss of electrons by a substance during a chemical reaction Reduction: the gain of electrons by a substance
More informationFind the oxidation numbers of each element in a reaction and see which ones have changed.
Find the oxidation numbers of each element in a reaction and see which ones have changed. Rules for oxidation numbers: An element that is not in a compound has an oxidation number of zero (0) Group 1 Metals
More informationUNIT 10 Reduction/Oxidation Reactions & Electrochemistry NOTES
Name Period CRHS Academic Chemistry UNIT 10 Reduction/Oxidation Reactions & Electrochemistry NOTES Quiz Date Lab Dates Exam Date Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry
More informationUnit 5 Part 2: Redox Reactions and Electrochemistry
Unit 5 Part 2: Redox Reactions and Electrochemistry Oxidation Numbers Oxidizing and Reducing Agents Balancing Redox Reactions Acidic solutions Basic solutions Galvanic Cells Nernst Equation This reaction
More informationREDOX AND ELECTROCHEMISTRY
SOUTH HIGH SCHOOL REDOX AND ELECTROCHEMISTRY Regents Chemistry Dr. Lombardo NAME Content Objectives REDOX & ELECTROCHEMISTRY What will students know and be able to do by the end of this instructional unit?
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 informationmccord (pmccord) HW11 Electrochemistry I mccord (51520) 1
mccord (pmccord) HW11 Electrochemistry I mccord (51520) 1 This print-out should have 27 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001
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 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 information*KEY* * KEY * Mr. Dolgos Regents Chemistry NOTE PACKET. Unit 10: Electrochemistry (Redox) REDOX NOTEPACKET 1
*KEY* * KEY * Mr. Dolgos Regents Chemistry NOTE PACKET Unit 10: Electrochemistry (Redox) REDOX NOTEPACKET 1 *KEY* * KEY * UNIT 10: Electrochemistry (Redox) Anode Cathode Electrochemical Cell Electrode
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 informationZn + Cr 3+ Zn 2+ + Cr. 9. neutrons remain the same: C. remains the same. Redox/Electrochemistry Regents Unit Review. ANSWERS
Redox/Electrochemistry Regents Unit Review. ANSWERS 1. ½ red = Cr 3+ + 3e Cr 2. ½ ox = Zn Zn +2 + 2e 3. Balanced = 3Zn + 2Cr 3+ 3Zn +2 + 2Cr 4. Zn loses electrons, 2Cr 3+ gains electrons Zn + Cr 3+ Zn
More informationChemistry 30 Review Test 3 Redox and Electrochemistry /55
Chemistry 30 Review Test 3 Redox and Electrochemistry /55 Part I Multiple choice / Numerical Response Answer the following multiple choice questions on the scantron sheet. Answer the numerical response
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 informationUnit #8, Chapter 10 Outline Electrochemistry and Redox Reactions
Unit #8, Chapter 10 Outline Electrochemistry and Redox Reactions Lesson Topics Covered Homework Questions and Assignments 1 Introduction to Electrochemistry definitions 1. Read pages 462 467 2. On page
More informationAn oxidation-reduction (redox) reaction involves the transfer of electrons (e - ). Sodium transfers its electrons to chlorine
Oxidation-Reduction An oxidation-reduction (redox) reaction involves the transfer of electrons (e - ). Sodium transfers its electrons to chlorine 2 Chemists need a way to keep track of what happens in
More informationS 8 + F 2 SF 6 4/9/2014. iclicker Participation Question: Balance the following equation by inspection: H + + Cr 2 O 7 + C 2 H 5 OH
Today: Redox Reactions Oxidations Reductions Oxidation Numbers Half Reactions Balancing in Acidic Solution Balancing in Basic Solution QUIZ 3 & EXAM 3 moved up by one day: Quiz 3 Wednesday/Thursday next
More informationChapter 4; Reactions in Aqueous Solutions. Chapter 4; Reactions in Aqueous Solutions. V. Molarity VI. Acid-Base Titrations VII. Dilution of Solutions
Chapter 4; Reactions in Aqueous Solutions I. Electrolytes vs. NonElectrolytes II. Precipitation Reaction a) Solubility Rules III. Reactions of Acids a) Neutralization b) Acid and Carbonate c) Acid and
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 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 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 informationWhat is the importance of redox reactions? Their importance lies in the fact that we can use the transfer of electrons between species to do useful
What is the importance of redox reactions? Their importance lies in the fact that we can use the transfer of electrons between species to do useful work. This is accomplished by constructing a voltaic
More information(c) In marble, we assign calcium ion an oxidation number of +2, and oxygen a value of 2. We can determine the value of carbon in CaCO 3 as follows:
Example Exercise 17.1 Calculating Oxidation Numbers for Carbon Calculate the oxidation number for carbon in each of the following compounds: (a) diamond, C (b) dry ice, CO 2 (c) marble, CaCO 3 (d) baking
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 informationIf a piece of magnesium is placed in an aqueous solution of copper (II) sulfate, the magnesium displaces the copper in a single displacement reaction.
5.3 REDOX Reactions Half-reactions from Full Redox Equations If a piece of magnesium is placed in an aqueous solution of copper (II) sulfate, the magnesium displaces the copper in a single displacement
More informationElectrochemical Cells: Virtual Lab
Electrochemical Cells: Virtual Lab Electrochemical cells involve the transfer of electrons from one species to another. In these chemical systems, the species that loses electrons is said to be oxidized
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 informationIf you like us, please share us on social media. The latest UCD Hyperlibrary newsletter is now complete, check it out.
Sign In Forgot Password Register username username password password Sign In If you like us, please share us on social media. The latest UCD Hyperlibrary newsletter is now complete, check it out. ChemWiki
More informationChapter 19 ElectroChemistry
Chem 1046 General Chemistry by Ebbing and Gammon, 9th Edition George W.J. Kenney, Jr, Professor of Chemistry Last Update: 11July2009 Chapter 19 ElectroChemistry These Notes are to SUPPLIMENT the Text,
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 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-Reduction (Redox) Reactions (4.4) 2) The ox. state of an element in a simple ion is the charge of the ion. Ex:
Redox reactions: Oxidation-Reduction (Redox) Reactions (4.4) Oxidation & reduction always occur simultaneously We use OXIDATION NUMBERS to keep track of electron transfers Rules for Assigning Oxidation
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 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 informationChapter Four. Chapter Four. Chemical Reactions in Aqueous Solutions. Electrostatic Forces. Conduction Illustrated
1 Electrostatic Forces 2 Chemical Reactions in Aqueous Solutions Unlike charges (+ and ) attract one another. Like charges (+ and +, or and ) repel one another. Conduction Illustrated 3 Arrhenius s Theory
More informationhttp://redoxanswers.weebly.com REDOX LESSON LEARNING GOALS http://redoxanswers.weebly.com Lesson 1: Introduction to Redox Relate to examples of oxidation-reduction reactions in the real-world. Understand
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 informationPage 1 Name: 2Al 3+ (aq) + 3Mg(s) 3Mg 2+ (aq) + 2Al(s) Fe 2 O 3 + 2Al Al 2 O 3 + 2Fe
9666-1 - Page 1 Name: 1) What is the oxidation number of chromium in the chromate ion, CrO 2-4? A) +8 B) +3 C) +2 D) +6 2) What is the oxidation number of sulfur in Na 2 S 2 O 3? A) +6 B) +4 C) +2 D) -1
More informationREDOX REACTIONS. Chapters 4, 19.1 & 19.2 M. Shozi CHEM110 / 2014
REDOX REACTIONS Chapters 4, 19.1 & 19.2 M. Shozi CHEM110 / 2014 REDOX REACTIONS Reactions involve the transfer of electrons between reactants When a substance loses electrons, it undergoes oxidation: Ca(s)
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 informationElectrochemistry. 1. For example, the reduction of cerium(iv) by iron(ii): Ce 4+ + Fe 2+ Ce 3+ + Fe 3+ a. The reduction half-reaction is given by...
Review: Electrochemistry Reduction: the gaining of electrons Oxidation: the loss of electrons Reducing agent (reductant): species that donates electrons to reduce another reagent. Oxidizing agent (oxidant):
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 informationThe Nature of Redox. Both oxidation and reduction processes occur together. Each half of the full redox reaction is a. Oxidizing and Reducing Agents
V. ELECTROCHEMISTRY V.1 INTRODUCTION TO OXIDATION AND REDUCTION Key Question: How are electrons gained or lost? ELECTROCHEMISTRY is the study of oxidation and reduction reactions in which chemical species
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 informationCHAPTER 12. Practice exercises
CHAPTER 12 Practice exercises 12.1 2Al(s) + 3Cl 2 (g) 2AlCl 3 (aq) Aluminium is oxidised and is therefore the reducing agent. Chlorine is reduced and is therefore the oxidising agent. 12.3 First the oxidation
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 informationName Period Date. Ch. 19: Oxidation-Reduction Reactions Homework
Name Period Date Ch. 19: OxidationReduction Reactions Homework Answer each of the following questions in as much detail as you can. Be sure to show all your work for any calculations and follow all rules
More informationALE 23. Balancing Redox Reactions. How does one balance a reaction for both matter and charge?
Name Chem 163 Section: Team Number: ALE 23. Balancing Redox Reactions (Reference: Section 4.5 (pp. 158 166) and 21.1 Silberberg 5 th edition) How does one balance a reaction for both matter and charge?
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 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 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 information