17.1 Redox Reactions. Oxidation Numbers. Assigning Oxidation Numbers. Redox Reactions. Ch. 17: Electrochemistry 12/14/2017. Creative Commons License

Size: px
Start display at page:

Download "17.1 Redox Reactions. Oxidation Numbers. Assigning Oxidation Numbers. Redox Reactions. Ch. 17: Electrochemistry 12/14/2017. Creative Commons License"

Transcription

1 Ch. 17: Electrochemistry Electric vehicles contain batteries that can be recharged, thereby using electric energy to bring about a chemical change and vice versa. (credit: modification of work by Robert Couse-Baker) Electrodeposition of metals: letter&utm_campaign=cen Chemistry: OpenStax 1 Creative Commons License Images and tables in this file have been used from the following sources: OpenStax: Creative Commons Attribution License 4.0. ChemWiki (CC BY-NC-SA 3.0): Unless otherwise noted, the StatWiki is licensed under a Creative Commons Attribution- Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at Principles of General Chemistry (CC BY-NC-SA 3.0): Redox Reactions Electrochemistry is the study of batteries (Galvanic Cells or voltaic cells): using a chemical reaction to generate electricity. Reactions in batteries are redox (oxidation-reduction) reactions in which one element gains electrons and another loses electrons. These two processes MUST happen together. Assign oxidation numbers to determine what is oxidized and what is reduced; oxidizing agent and reducing agent. Review Section 4.2 for assigning oxidation numbers; determining what is oxidized/reduced/oxidizing agent/reducing agent; activity series. Electrodeposition of metals: wsletter&utm_medium=newsletter&utm_campaign=cen 3 Oxidation Numbers 1) Elements in their natural states are 0. 2) Elements in binary ionic compounds are the same as their charges. (e.g., MgCl 2 ) 3) H: usually +1, except with alkali metals (LiH, NaH, etc.) Examples: H 2 O, H 2 (g), H 2 SO 4 4) O: usually -2, except in peroxides (H 2 O 2, K 2 O 2 ) Examples: H 2 O, KMnO 4, Na 2 O 5) The non-oxygen element in a polyatomic ion has to be determined from the other oxidation numbers. Examples: NO 3-, MnO 4-, Cr 2 O Oxidation: loss of electrons Reduction: gain of electrons LEO the lion goes GER Redox Reactions The substance oxidized is also called the reducing agent (it caused the other substance to be reduced). The substance reduced is also called the oxidizing agent (it caused the other substance to be oxidized). Zn(s) + CuCl 2 (aq) Cu(s) + ZnCl 2 (aq) Assigning Oxidation Numbers Assign oxidation numbers to each element in the equation below. Then identify the substance oxidized, reduced, the oxidizing agent, and the reducing agent. Cu(NO 3 ) 2 (aq) + Mg(s) Cu(s) + Mg(NO 3 ) 2 (aq) Elements get oxidized or reduced. 5 Compounds are oxidizing or reducing agents. 6 1

2 Balancing Redox Reactions Simple redox reactions can be balanced using half-reactions to balance atoms and charges. Zn(s) + Al 3+ (aq) Al(s) + Zn 2+ (aq) Separate equation into the oxidation half reaction and the reduction half reaction, including electrons. Then balance the equations so electrons cancel. Combine half reactions into one equation; atoms and charges have to balance. 7 Redox Reactions Figure 17.3: Cu (s) + 2 Ag + (aq) Cu 2+ (aq) + 2 Ag(s) When a clean piece of copper metal is placed into a clear solution of silver nitrate (a), an oxidation-reduction reaction occurs that results in the exchange of Cu 2+ for Ag + ions in solution. As the reaction proceeds (b), the solution turns blue (c) because of the copper ions present, and silver metal is deposited on the copper strip as the silver ions are removed from solution. (credit: modification of work by Mark Ott) 8 Figure 17.4: If we separate the halfreactions into two separate containers, we can connect the metals via wire in a galvanic cell. Voltaic Cell: movie Electron motion in a cell 17.2 Galvanic Cells 9 Galvanic Cells - Components : Oxidation reaction (both vowels); mass of electrode decreases; solution charge increases; negative charge Metal is placed in its own solution (e.g., Cu(s) in Cu(NO 3 ) 2 (aq)) : Reduction reaction (both consonants); mass of electrode increases; solution charge decreases; positive charge Metal is placed in its own solution (e.g., Ag(s) in AgNO 3 (aq)) Wire: Electrons are transferred across a wire (through a voltmeter) from the anode (-) to the cathode (+) The cell potential, E (or Electromotive Force, EMF), is measured in Volts (V) Salt bridge - soluble salt solution used to maintain neutral charges of ions in each solution; cations travel toward cathode, anions toward anode 10 Galvanic Cells - Components Figure 17.5: A nonreactive, or inert, platinum wire allows electrons from the left beaker to move into the right beaker. Overall reaction is: Mg(s) + 2H + (aq) Mg 2+ (aq) + H 2 (g). Inert electrodes allow electrons to transfer but don t take part in the reaction. Non-metal Electrodes Zn/H2 cell: movie 12 2

3 Cu(s) Cu 2+ (1 M) Ag + (1 M) Ag(s) anode is phase boundary (separates solid from ions) is salt bridge electrons flow from left to right The Mg/H 2 Galvanic cell is represented by the notation: Mg(s) Mg 2+ (aq) H + (aq), H 2 (g) Pt(s). Write the cell notation for the reaction: 3 Zn(s) + 2 Al 3+ (aq) 2 Al(s) + 3 Zn 2+ (aq) Zn(s) Zn 2+ (aq) Al 3+ (aq) Al(s) Cell Notation cathode Standard Reduction Potentials The standard potential of a Galvanic cell is measured by a voltmeter and is called the cell potential (E o cell ), measured in Volts (V). The cell potential of a battery results from the difference in the electrical potentials for each electrode. The hydrogen electrode has been assigned a potential of 0 V, and is referred to as the Standard Hydrogen Electrode (SHE). 2H + (aq) + 2e H 2 (g) E o red = 0.0 V E = electromotive force (EMF) is the electrical potential that pushes e - away from anode (-) and pulls them toward cathode (+). Also called cell potential or cell voltage. 14 Standard Reduction Potentials In the Galvanic cell below, hydrogen is the anode (oxidized) and copper is the cathode (reduced). : H 2 (g) 2 H + (aq) + 2 e - E o ox = 0 V : Cu 2+ (aq) + 2e - Cu(s) E o red = V Figure 17.7 Standard Reduction Potentials In the Cu/Ag Galvanic cell, we can calculate the standard cell potential (E o cell) using cell potentials of each half reaction. : Cu(s) Cu 2+ (aq) + 2e - E o ox = V : Ag + (aq) + e - Ag(s) E o red = 0.80 V E o cell = E o red + E o ox = 0.80 V V = 0.46 V Notice that the copper half reaction is flipped from the previous example. When we reverse an equation, we change the sign of the potential (electron flow is reversed). How do we determine which half-reaction will be oxidized and which will be reduced? It depends on a species ability to reduce another substance. Standard Reduction Potentials Standard Reduction Potentials at 25 o C (See Table 17.2 partial table). Full list is in Appendix L (Standard Electrode (Half-Cell) Potentials. Increasing strength as oxidizing agents Half-Reaction Increasing strength as reducing agents E o red (V) F 2 (g) + 2e 2F (aq) Br 2 (l) + 2e 2Br (aq) Ag + (aq) + e Ag(s) Cu 2+ (aq) + 2e Cu(s) H + (aq) + 2e H 2 (g) 0.00 Pb 2+ (aq) + 2e Pb(s) Cd 2+ (aq) + 2e Cd(s) Zn 2+ (aq) + 2e Zn(s) Li + (aq) + e Li(s)

4 Activity Series Cell Potentials F 2 (g) + 2e - 2F - (aq) E o red = V This is the most positive E o red value. Makes sense: F 2 is the most electronegative element and easily gains an electron. F 2 (g) is easiest to reduce, a good oxidizing agent. Li + (aq) + e - Li(s) E o red = V This is the most negative E o red. Li + (aq) is hardest to reduce. Li(s) Li + (aq) + e - E o ox = V Li(s) is easiest to oxidize (easily loses an electron), a good reducing agent. 20 Based on their E o red values, determine the specific element or ion (include physical states) that is the: best oxidizing agent best reducing agent Au e - Au(s) Br 2 (l) + 2e - 2Br - (aq) Pb e - Pb(s) Ni e - Ni(s) Cell Potentials E o red = V E o red = V E o red = V E o red = V Standard Cell Potentials When given two half reactions, the more positive E o red will be the reduction half-reaction (no change). The more negative (or less positive) E o red will be reversed to give the oxidation half-reaction (E o ox = - E o red). Positive E o cell means the reaction is product-favored. The reaction will go forward until the battery dies. die when salt bridge, anode, or cathode runs out of material. Therefore, we want two half reactions that yield the most positive E o cell value. E o cell = E o ox + E o red For each pair of electrodes below, determine what will be the anode and what will be the cathode. Calculate E o cell for each combination. 1) Cu(s) and Cr(s) 2) Cu(s) and Mn(s) 3) Cu(s) and Au(s) Half-Reaction Au 3+ (aq) + 3e - Au(s) E red (V) Cu 2+ (aq) + 2e - Cu(s) Cu/Cr: Cr(s) anode, Cu(s) cathode; E o cell = V Cu/Mn: Mn(s) anode, Cu(s) cathode; E o cell = V Cu/Au: Cu(s) anode, Au(s) cathode; E o cell = V Example 17.4 Standard Cell Potentials Cr 3+ (aq) + 3e - Cr(s) Mn 2+ (aq) + 2e - Mn(s) The Nernst Equation E o cell is related to the thermodynamic quantity G o (both determine whether a reaction is reactant-favored or product-favored). Chemical energy in a Galvanic cell can do work, which is the product of the charge transferred (Coulombs discovered by Millikan and his Oil Drop experiment) and the potential difference (Volts). work = Volts x Coulombs = J F is Faraday s constant 24 4

5 The Nernst Equation G o = - nfe o cell n is the number of moles electrons F is Faraday s constant (96,500 C/mol e ) G = G o + RT ln Q (from Chapter 16) substitute nfe for G -nfe = -nfe o + RT ln Q (divide both sides by nf) E = E o (RT/nF) ln Q Nernst equation Non-Standard Cell Potential E = E o (RT/nF) ln Q Nernst equation When Q > 1, E < E ; When Q < 1, E > E Variations on this equation: E = E o cell - (2.303 RT) / nf log Q E = E o cell - ( V / n) log Q (at 25 o C) also on equation sheet At equilibrium, E = 0 and Q = K The equation becomes: E o cell = (RT/nF) ln K Variation on this equation: E o cell = ( V / n) log K (at 25 o C) Summary of Relationships Positive E o cell value G o is negative K is large Reaction is product-favored Negative E o cell value G o is positive K is small Reaction is reactant-favored G o, K from E o cell Calculate G o and K for a product-favored reaction at 25 o C using a Mg(s)-Al(s) Galvanic cell. Half-Reaction E red (V) Al 3+ (aq) + 3e Al(s) Mg 2+ (aq) + 2e Mg(s) Example Spontaneity at Nonstandard Conditions Calculate the cell potential, E, for the Mg-Al galvanic cell when [Mg 2+ ] = 0.60 M and [Al 3+ ] = M at 50 o C. Half-Reaction E red (V) Al 3+ (aq) + 3e Al(s) Mg 2+ (aq) + 2e Mg(s) Calculations Practice Calculate the cell potential, E, at 298 K when [Fe 2+ ] = 0.62 M, [Fe 3+ ] = 2.1 M and [Cd 2+ ] = 0.15 M? Is it spontaneous? Fe 3+ (aq) + e - Fe 2+ (aq) Cd 2+ (aq) + 2e - Cd(s) E o red = V E o red = V Balanced equation: Cd(s) + 2Fe 3+ (aq) 2Fe 2+ (aq) + Cd 2+ (aq) E o cell = V V = V Q = [Fe 2+ ] 2 [Cd 2+ ]/[Fe 3+ ] 2 = ( *0.15)/(2.1 2 ) = E = E o cell - (RT/nF) ln Q = V (spontaneous) Example

6 Calculate the cell potential at 25 o C when [Pb(NO 3 ) 2 ] = 0.88 M and [Ag(NO 3 )] = 0.14 M Ag + (aq) + e Ag(s) Pb 2+ (aq) + 2e - Pb(s) E o red = V E o red = V Write the short-hand notation of this reaction. Side note: gas pressures can also be used to calculate Q. E o cell = V V = V; n = 2 mol e - Q = (0.88 M) / (0.14 M) 2 = 44.9 E = V Calculations Practice Corrosion The term corrosion generally refers to the deterioration of a metal by an electrochemical process (e.g., rusting of iron). A view from the top of the Statue of Liberty, showing the green patina coating the statue. The patina is formed by corrosion of the copper skin of the statue, which forms a thin layer of an insoluble compound that contains copper(ii), sulfate, and hydroxide ions. (a) The Statue of Liberty is covered with a copper skin, and was originally brown, as shown in this painting. (b) Exposure to the elements has resulted in the formation of the blue-green patina seen today. Image from Principles of General Chemistry CC-BY-NC-SA license Corrosion of iron Figure 17.7: Once the paint is scratched on a painted iron surface, corrosion occurs and rust begins to form. The speed of the spontaneous reaction is increased in the presence of electrolytes, such as the sodium chloride used on roads to melt ice and snow or in salt water. Cathodic Protection Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded sacrificial metal to act as the anode. The sacrificial metal then corrodes instead of the protected metal. Common applications are: steel water or fuel pipelines (e.g., water heaters), ship and boat hulls, metal reinforcement bars in concrete buildings and structures, and galvanized steel (zinc is sacrificial metal to protect steel metal from rusting). Source: Electrolysis Electrolysis The use of electric energy to drive a non-spontaneous chemical reaction (running a battery in reverse) is called electrolysis and uses an electrolytic cell. Electrolysis of molten sodium chloride; E o cell = 4 V Figure Water doesn t naturally decompose into hydrogen and oxygen. Electrolysis of water: E o cell = V; G o = kj/mol : 2H 2 O(l) O 2 (g) + 4H + (aq) + 4e : 4H + (aq) + 4e 2H 2 (g) 2H 2 O(l) O 2 (g) + 2H 2 (g) Figure 17.20: Water decomposes into oxygen and hydrogen gas during electrolysis. Sulfuric acid was added to increase the concentration of hydrogen ions and the total number of ions in solution, 35 2Cl (l) Cl 2 (g) + 2e 2Na + (l) + 2e 2Na(l) 2Na + (l) + 2Cl (l) 2Na(l) + Cl 2 (g) 36 6

7 Electrolysis Faraday developed the quantitative treatment of electrolysis. 2Cl (l) Cl 2 (g) + 2e Ca 2+ (l) + 2e Ca(l) Ca 2+ (l) + 2Cl (l) Ca(l) + Cl 2 (g) Charge (C) = Current (A) x time (s) What mass of chlorine gas can be produced when 45.2 A is passed through the cell for 1.50 hr? Electrolysis If a constant current of A is passed through an electrolytic cell containing molten MgCl 2 and produces 7.44 g of Mg, how long does the current have to be passed? Mg 2+ (l) + 2e Mg(l) 37 Example Figure 17.4: Lead Storage (Car) 6 cells 2 V per cell 12 V total Rechargeable 17.5 and Fuel Cells Pb(s) + 2HSO 4 (aq) PbSO 4 (s) + H + (aq) + 2e PbO 2 (s) + 3H + (aq) + HSO 4 (aq) + 2e PbSO 4 (s) + 2H 2 O(l) Pb(s) + PbO 2 (s) + 2H 2 SO 4 (aq) 2PbSO 4 (s) + 2H 2 O(l) Figure 17.10: Dry Cell (or Laclanche) : Zinc container (anode), Graphite rod (cathode), 1.5 V It is important to remember that the voltage delivered by a battery is the same regardless of the size of a battery. For this reason, D, C, A, AA, and AAA batteries all have the same voltage rating. However, larger batteries can deliver more moles of electrons. As the zinc container oxidizes, its contents eventually leak out, so this type of battery should not be left in any electrical device for extended periods. Zn(s) Zn 2+ (aq) + 2e 2 NH 4+ (aq) + 2MnO 2 (s) + 2e Mn 2 O 3 (s) + 2NH 3 (aq) + H 2 O(l) Zn(s) + 2NH 4+ (aq) + 2MnO 2 (s) Zn 2+ (aq)+ Mn 2 O 3 (s) + 2NH 3 (aq) + H 2 O(l) 40 9 Volt 6 x 1.5 V Dry Cell batteries connected in series Lithium ion (Rechargeable) batteries: charge flows between the electrodes as the lithium ions move between the anode and cathode Cell potential: 3.7 V 41 Li(s) Li + + e Li + (aq) + CoO 2 + e LiCoO 2 (s) Li + (s) + CoO 2 LiCoO 2 (s) 42 7

8 Tesla Motors 60 kwh battery rated to deliver 230 miles (208 by EPA) 85 kwh battery rated to deliver 320 miles (265 by EPA) Contains 7,104 lithium-ion battery cells in 16 modules wired in series. The battery pack uses Ni-Co-Al cathodes. Fuel Cells; E o cell = 1.23 V In this hydrogen fuel-cell schematic, oxygen from the air reacts with hydrogen, producing water and electricity. How it works 43 2H 2 (g) + 2O 2- (aq) 2H 2 O(l) + 4e O 2 (aq) + 4e 2O 2- (aq) 2H 2 (g) + O 2 (g) 2H 2 O(l) 44 Figure 17.11: Alkaline : Zinc container (anode), Graphite rod (cathode), 1.43 V Alkaline batteries were designed as direct replacements for zinc-carbon (dry cell) batteries in the 1950 s. They can deliver about 3 5x the energy of a zinc-carbon dry cell battery of similar size. NiCd : Nickel-plated cathode and cadmium-plated anode. NiCd batteries use a jelly-roll design that significantly increases the amount of current the battery can deliver as compared to a similarsized alkaline battery. Zn(s) + 2OH - (aq) ZnO(s) + H 2 O(l) + 2e 2MnO 2 (s) +H 2 O(l) + 2e Mn 2 O 3 (s) + 2OH - (aq) Cd(s) + 2OH - (aq) Cd(OH) 2 (s) + 2e NiO 2 (s) + 2H 2 O(l) + 2e Ni(OH0 2 (s) + 2OH - (aq) Zn(s) + 2MnO 2 (s) ZnO(s)+ Mn 2 O 3 (s) 45 Cd(s) + NiO 2 (s)+ 2H 2 O(l) Cd(OH) 2 (s)+ Ni(OH) 2 (s) 46 8

Oxidation-Reduction Review. Electrochemistry. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions. Sample Problem.

Oxidation-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 information

ELECTROCHEMISTRY OXIDATION-REDUCTION

ELECTROCHEMISTRY 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 information

Chapter 17. Electrochemistry

Chapter 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 information

Electrochemistry. Galvanic Cell. Page 1. Applications of Redox

Electrochemistry. Galvanic Cell. Page 1. Applications of Redox Electrochemistry Applications of Redox Review Oxidation reduction reactions involve a transfer of electrons. OIL- RIG Oxidation Involves Loss Reduction Involves Gain LEO-GER Lose Electrons Oxidation Gain

More information

Chapter 20 Electrochemistry

Chapter 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 information

Electrochemistry. 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. 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 information

Lecture Presentation. Chapter 18. Electrochemistry. Sherril Soman Grand Valley State University Pearson Education, Inc.

Lecture 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 information

Ch 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. 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 information

Electrochemistry Pulling the Plug on the Power Grid

Electrochemistry 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 information

Chapter 18 Electrochemistry

Chapter 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 information

Chemistry: The Central Science. Chapter 20: Electrochemistry

Chemistry: 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 information

Introduction to electrochemistry

Introduction 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 information

Chapter Nineteen. Electrochemistry

Chapter 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 information

Oxidation-Reduction (Redox)

Oxidation-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 information

Chapter 17 Electrochemistry

Chapter 17 Electrochemistry Chapter 17 Electrochemistry 17.1 Galvanic Cells A. Oxidation-Reduction Reactions (Redox Rxns) 1. Oxidation = loss of electrons a. the substance oxidized is the reducing agent 2. Reduction = gain of electrons

More information

Electron Transfer Reactions

Electron Transfer Reactions ELECTROCHEMISTRY 1 Electron Transfer Reactions 2 Electron transfer reactions are oxidation- reduction or redox reactions. Results in the generation of an electric current (electricity) or be caused by

More information

Chapter 20. Electrochemistry

Chapter 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 information

Redox reactions & electrochemistry

Redox 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

Lecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education

Lecture 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 information

CHEMISTRY 13 Electrochemistry Supplementary Problems

CHEMISTRY 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 information

How to Assign Oxidation Numbers. Chapter 18. Principles of Reactivity: Electron Transfer Reactions. What is oxidation? What is reduction?

How to Assign Oxidation Numbers. Chapter 18. Principles of Reactivity: Electron Transfer Reactions. What is oxidation? What is reduction? Chapter 18 Principles of Reactivity: Electron Transfer Reactions What is oxidation? When a molecule/ion loses electrons (becomes more positive) Whatever is oxidized is the reducing agent What is reduction?

More information

Lecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education, Inc.

Lecture 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 information

Chapter 20 Electrochemistry

Chapter 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 information

Lecture Presentation. Chapter 20. Electrochemistry. James F. Kirby Quinnipiac University Hamden, CT Pearson Education

Lecture 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 information

Chapter 18. Electrochemistry

Chapter 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

SCHOOL YEAR CH- 19 OXIDATION-REDUCTION REACTIONS SUBJECT: CHEMISTRY GRADE: 12

SCHOOL 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 information

CHAPTER 5 REVIEW. C. CO 2 D. Fe 2 O 3. A. Fe B. CO

CHAPTER 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 information

Chapter 18 Electrochemistry. Electrochemical Cells

Chapter 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 information

Chapter 20. Electrochemistry

Chapter 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 information

Electrochemistry 1 1

Electrochemistry 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 information

Electrochemistry. Review oxidation reactions and how to assign oxidation numbers (Ch 4 Chemical Reactions).

Electrochemistry. 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 information

Chemistry 102 Chapter 19 OXIDATION-REDUCTION REACTIONS

Chemistry 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 information

Chapter 18. Electrochemistry

Chapter 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 information

Electrochem: It s Got Potential!

Electrochem: 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 information

Oxidation 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. 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 information

Electrode Potentials and Their Measurement

Electrode 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 information

Electrochemistry Pearson Education, Inc. Mr. Matthew Totaro Legacy High School AP Chemistry

Electrochemistry 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 information

Chapter 18: Electrochemistry

Chapter 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 information

Part One: Introduction. a. Chemical reactions produced by electric current. (electrolysis)

Part 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 information

Review. Chapter 17 Electrochemistry. Outline. Voltaic Cells. Electrochemistry. Mnemonic

Review. 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 information

Electrochemistry. 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. 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 information

Chapter 19 ElectroChemistry

Chapter 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 information

CHEM Principles of Chemistry II. Chapter 17 - Electrochemistry

CHEM Principles of Chemistry II. Chapter 17 - Electrochemistry CHEM 1212 - Principles of Chemistry II Chapter 17 - Electrochemistry electrochemistry is best defined as the study of the interchange of chemical and electrical energy 17.1 Galvanic Cells an oxidation-reduction

More information

Chapter 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 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 information

Electrochemistry (Galvanic and Electrolytic Cells) Exchange of energy in chemical cells

Electrochemistry (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 information

Oxidation & Reduction (Redox) Notes

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 information

Oxidation-reduction reactions = chemical reactions in which the oxidation state of one or more substance changes (redox reactions).

Oxidation-reduction reactions = chemical reactions in which the oxidation state of one or more substance changes (redox reactions). Chapter 20. Electrochemistry Common Student Misconceptions Students should be encouraged to review section 4.4. Students often think that oxidation must necessarily mean adding oxygen. Students often have

More information

Dr. Anand Gupta

Dr. 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 information

AP CHEMISTRY NOTES 12-1 ELECTROCHEMISTRY: ELECTROCHEMICAL CELLS

AP CHEMISTRY NOTES 12-1 ELECTROCHEMISTRY: ELECTROCHEMICAL CELLS AP CHEMISTRY NOTES 12-1 ELECTROCHEMISTRY: ELECTROCHEMICAL CELLS Review: OXIDATION-REDUCTION REACTIONS the changes that occur when electrons are transferred between reactants (also known as a redox reaction)

More information

17.1 Redox Chemistry Revisited

17.1 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 information

Chapter 20. Electrochemistry. Chapter 20 Problems. Electrochemistry 7/3/2012. Problems 15, 17, 19, 23, 27, 29, 33, 39, 59

Chapter 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 information

Electrochemistry. (Hebden Unit 5 ) Electrochemistry Hebden Unit 5

Electrochemistry. (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 information

Chapter 19: Electrochemistry

Chapter 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 information

General 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 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 information

The Nature of Redox. Both oxidation and reduction processes occur together. Each half of the full redox reaction is a. Oxidizing and Reducing Agents

The 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 information

Electrochemistry Worksheets

Electrochemistry Worksheets Electrochemistry Worksheets Donald Calbreath, Ph.D. Say Thanks to the Authors Click http://www.ck12.org/saythanks (No sign in required) To access a customizable version of this book, as well as other interactive

More information

Q1. Why does the conductivity of a solution decrease with dilution?

Q1. Why does the conductivity of a solution decrease with dilution? Q1. Why does the conductivity of a solution decrease with dilution? A1. Conductivity of a solution is the conductance of ions present in a unit volume of the solution. On dilution the number of ions per

More information

Oxidation (oxidized): the loss of one or more electrons. Reduction (reduced): the gain of one or more electrons

Oxidation (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 information

CHAPTER 12. Practice exercises

CHAPTER 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 information

Chapter 19: Oxidation - Reduction Reactions

Chapter 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 information

Section Electrochemistry represents the interconversion of chemical energy and electrical energy.

Section 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 information

Electrochemistry. Outline

Electrochemistry. 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 information

N Goalby chemrevise.org

N Goalby chemrevise.org Redox Equilibria Electrochemical cells This type of cell can be called a Voltaic cell or Galvanic cell. Voltaic cells convert energy from spontaneous, exothermic chemical processes to electrical energy.

More information

Chapter Objectives. Chapter 13 Electrochemistry. Corrosion. Chapter Objectives. Corrosion. Corrosion

Chapter 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 information

Chapter 9 Oxidation-Reduction Reactions. An Introduction to Chemistry by Mark Bishop

Chapter 9 Oxidation-Reduction Reactions. An Introduction to Chemistry by Mark Bishop Chapter 9 Oxidation-Reduction Reactions An Introduction to Chemistry by Mark Bishop Chapter Map Oxidation Historically, oxidation meant reacting with oxygen. 2Zn(s) + O 2 (g) 2ZnO(s) Zn Zn 2+ + 2e or 2Zn

More information

Electrochemical Cells

Electrochemical 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 information

(18) WMP/Jun10/CHEM5

(18) WMP/Jun10/CHEM5 Electrochemistry 18 7 The electrons transferred in redox reactions can be used by electrochemical cells to provide energy. Some electrode half-equations and their standard electrode potentials are shown

More information

20.1 Consider the Brønsted-Lowry acid-base reaction and the redox reaction below. + A

20.1 Consider the Brønsted-Lowry acid-base reaction and the redox reaction below. + A 20 Electrochemistry Visualizing Concepts 20.1 Consider the Brønsted-Lowry acid-base reaction and the redox reaction below. HA + B BH + + A HA H + + A B + H + BH + X(red) + Y + (ox) X + (ox) + Y(red) X(red)

More information

SHOCK TO THE SYSTEM! ELECTROCHEMISTRY

SHOCK 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 information

We can use chemistry to generate electricity... this is termed a Voltaic (or sometimes) Galvanic Cell

We can use chemistry to generate electricity... this is termed a Voltaic (or sometimes) Galvanic Cell Unit 6 Electrochemistry Chemistry 020, R. R. Martin Electrochemistry Electrochemistry is the study of the interconversion of electrical and chemical energy. We can use chemistry to generate electricity...

More information

Chapter 18 problems (with solutions)

Chapter 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 information

Chapter 7. Oxidation-Reduction Reactions

Chapter 7. Oxidation-Reduction Reactions Chapter 7 Oxidation-Reduction Reactions Chapter Map Oxidation Historically oxidation meant reacting with oxygen. 2Zn(s) + O 2 (g) 2ZnO(s) Zn Zn 2+ + 2e or 2Zn 2Zn 2+ + 4e O + 2e O 2 or O 2 + 4e 2O 2 Oxidation

More information

Chapter 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) 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 information

1.11 Redox Equilibria

1.11 Redox Equilibria 1.11 Redox Equilibria Electrochemical cells Electron flow A cell has two half cells. The two half cells have to be connected with a salt bridge. Simple half cells will consist of a metal (acts an electrode)

More information

2. Using Half Cell Potentials and Latimer Diagrams. 100 measured half cell potentials generate 10,000 full reactions

2. 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 information

Electrochemistry C020. Electrochemistry is the study of the interconversion of electrical and chemical energy

Electrochemistry C020. Electrochemistry is the study of the interconversion of electrical and chemical energy Electrochemistry C020 Electrochemistry is the study of the interconversion of electrical and chemical energy Using chemistry to generate electricity involves using a Voltaic Cell or Galvanic Cell (battery)

More information

Chapter 20. Electrochemistry

Chapter 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 information

Introduction to Electrochemical reactions. Schweitzer

Introduction 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 information

the study of the interchange of and energy reactions are oxidationreduction

the study of the interchange of and energy reactions are oxidationreduction the study of the interchange of and energy reactions are oxidationreduction reactions. : oxidation loss of e -, reduction gaining of e - 1. Oxidation = loss of electrons; increase in charge a. the substance

More information

Electrochem 1 Electrochemistry Some Key Topics Conduction metallic electrolytic Electrolysis effect and stoichiometry Galvanic cell Electrolytic cell Electromotive Force (potential in volts) Electrode

More information

Redox and Electrochemistry

Redox 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 information

CHEM J-14 June 2014

CHEM 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 information

ELECTROCHEMISTRY. Oxidation/Reduction

ELECTROCHEMISTRY. 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 information

Practice Exam Topic 9: Oxidation & Reduction

Practice 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 information

Chapter 20. Electrochemistry

Chapter 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 information

Reactions in aqueous solutions Redox reactions

Reactions 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 information

Redox and Electrochemistry (BLB chapter 20, p.723)

Redox and Electrochemistry (BLB chapter 20, p.723) Redox and Electrochemistry (BLB chapter 20, p.723) Redox is short for reduction/oxidation Redox chemistry deals with changes in the oxidation states of atoms Oxidation States All atoms have an oxidation

More information

25. A typical galvanic cell diagram is:

25. 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 information

1.In which of the following is the oxidation number of the underlined element given incorrectly? oxidation number

1.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 information

Ch 18 Electrochemistry OIL-RIG Reactions

Ch 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 information

Introduction 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. 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 information

Chapter 18. Redox Reac)on. Oxida)on & Reduc)on 4/8/08. Electrochemistry

Chapter 18. Redox Reac)on. Oxida)on & Reduc)on 4/8/08. Electrochemistry Chapter 18 Electrochemistry Redox Reac)on One or more elements change oxida)on number all single displacement, and combus)on, some synthesis and decomposi)on Always have both oxida)on and reduc)on split

More information

Lecture 14. Thermodynamics of Galvanic (Voltaic) Cells.

Lecture 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 information

Homework 11. Electrochemical Potential, Free Energy, and Applications

Homework 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 information

Unit 13 Redox Reactions & Electrochemistry Ch. 19 & 20 of your book.

Unit 13 Redox Reactions & Electrochemistry Ch. 19 & 20 of your book. Unit 13 Redox Reactions & Electrochemistry Ch. 19 & 20 of your book. Early Booklet E.C.: + 2 Unit 13 Hwk. Pts.: / 32 Unit 13 Lab Pts.: / 32 Late, Incomplete, No Work, No Units Fees? Y / N Learning Targets

More information

Reducing Agent = a substance which "gives" electrons to another substance causing that substance to be reduced; a reducing agent is itself oxidized.

Reducing 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 information

Electrochemistry. Slide 1 / 144. Slide 2 / 144. Slide 3 / 144. Electrochemistry. Electrochemical Reactions

Electrochemistry. Slide 1 / 144. Slide 2 / 144. Slide 3 / 144. Electrochemistry. Electrochemical Reactions Slide 1 / 144 Electrochemistry Electrochemistry Slide 2 / 144 Electrochemistry deals with relationships between reactions and electricity In electrochemical reactions, electrons are transferred from one

More information

Chpt 20: Electrochemistry

Chpt 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 information

Unit 12 Redox and Electrochemistry

Unit 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 information

Chemistry 1011 TOPIC TEXT REFERENCE. Electrochemistry. Masterton and Hurley Chapter 18. Chemistry 1011 Slot 5 1

Chemistry 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 information