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Oxidation-Reduction and Electrochemistry

Electrochemistry refers to a set of chemical reactions which take place in solution between an electrode and an electrolyte. The reaction involves at least an electron transfer between these two entities. If a chemical reaction does not occur spontaneously and requires electrical energy to drive it, then the reaction is known as electrolysis. If the reaction instead spontaneously occurs and generates electrical energy in the process, like a battery, then this is known as a galvanic or voltaic cell. Within these electrochemical reactions, there is a subset of reactions occurring called redox reactions, which is just an abbreviated term for the ‘reduction-oxidation’ reactions. Reduction refers to the gain of electrons, while oxidation refers to the loss of electrons. In general, electrochemistry focuses on situations where oxidation and reduction reactions are separated in space, and connected in a circuit, such as in an electrochemical cell. An electrochemical cell consists of two half-cells where one is undergoing reduction, and the other oxidation. Connecting these half-cells by an external circuit generates and electrochemical potential due to the additive potentials of both oxidation and reduction. Such a phenomenon allows for the creation of batteries, which have the capability of generating and storing electrical energy. For example, the copper-zinc electrochemical cell is a common battery capable of producing a standard electrode potential of 1.1 V. Thus, understanding electrochemistry is extremely important for chemistry as a whole, as redox reactions are a fundamental component of almost all reaction mechanisms.

Categories within Oxidation-Reduction and Electrochemistry

Redox Reactions

Postings: 51

Redox Reactions refer to a set of chemical reactions which consist of an electron transfer and a change in oxidation state of the reactant species.

Electrochemical Cells

Postings: 26

An Electrochemical Cell is an experimental system capable of either generative electrical energy from two half cells, or facilitating the chemical reaction between two half cells through the introduction of electrical energy.

Electrochemical Potentials

Postings: 17

The Electrochemical Potential is a measurement of the energy stored in the chemical potential of redox reactions.

Batteries

Postings: 2

A Battery in electrochemistry refers to an electrochemical cell with the capability of producing and storing electrical energy.

Corrosion

Postings: 1

Corrosion, in electrochemistry, is the gradual destruction of an electrode caused by an electrochemical process.

Electrophoresis

Postings: 2

Electrophoresis refers to the movement of dispersed charged particles under the influence of an applied uniform electric field.

Molybdenum enzyme model compounds .

(a) The following complexes I, II, and III represent model compounds for the molybdenum-containing enzymes involved in oxygen-atom transfer (OAT) reactions. In each case assign the formal oxidation state of the metal centre and clearly show your reasoning: **Please see the attached document for the diagrams.** (b) So

Ferredoxins and Redox Couples

a) Comment on the applicability of [Fe2(S)2(SPh)4]^n shown below as a model for redox/spin states of [2Fe*2S] ferredoxin, given that the observed values of the effective magnetic moments are 0 and 1.75 for [Fe2(S)2(SPh)4]^-2 and [Fe2(S)2(SPh)4]^-3respectively b) Explaining your reasons, use the ^57Fe Mossbauer data below to

Glucose and Vanadium Pentoxide

With how many grams of each reactant (glucose and vanadium pentoxide) did you start and with how many grams of each product were produced for the oxidation of glucose (C6H12O6) by vanadium pentoxide in an acidic solution. The products are CO2, V3+, and H2O. You place stoichiometric amounts of the reactants into an evacuated 2.0

Energy from Hydrogen

Calculate the minimum energy required to produce molecular hydrogen from gas-phase water. Then compare this to the energy need to produce water electrochemically or photoelectrochemically. Finally, compare this to the energy needed to make this on a zirconia surface. Comment on why there are differences.

Redox Titration-Analysis of Bleach (Sodium Hypochlorite)

The active ingredient in many commercial liquid bleaches is sodium hypochlorite. The bottle lists the percentage of sodium hypochlorite as 6.0%. If the density of commercial bleach is 1.084 g/mL, how many mL of 0.150 M sodium thiosulfate is required to reach the end point in a titration similar to the one performed in this exper

Balancing Half-reactions Red-Ox

Use the following pair of half-reactions to design a galvanic cell. Then write in the proper coefficient for each of the species involved in the overall reaction. Water molecules and protons are not shown in the half-reactions, but they may be needed to the overall reaction. N2(g)->N2H5+(aq) E=-.023V MnO4-(aq) -> Mn2+ (

Balanced Molecular Ionic Net Equations

1. Calculate the concentration of a Pb(NO3)2 in a solution made up of 49.1 mg of solid Pb(NO3)2 (MW=33.22) dissolved in 65.00 mL of water (MW=18.02). 2. Write balanced molecular, ionic, and net equations for the following reactions. a. KCN(aq) + MgCI2(aq) - KCL (aq) +Mg(CN)2(aq) b. Zn(NO3)2 (aq) +H3PO4(aq)

Exam 5 Review Help

Want to verify answers for exam review. Question 1 Consider an electrochemical cell constructed from the following half cells, linked by an external circuit and by a KCl salt bridge: an Al(s) electrode in 1.0 M Al(NO3)3 solution a Pb(s) electrode in 1.0 M Pb(NO3)2 solution What is the balanced overall (net) cell rea

Just a check on my work

Last minute cram for finals tonight. I found these as pertains to my weak areas, so, just to see if I am doing ok, if I am wrong, please correct me-I can probably find where I went wrong! 1. What mass of solid CaO is needed to remove the sulfur dioxide from 1.0 x 106 m3 of air having an SO2 concentration of 1.5 x 10-9 M? Assu

Nickel Oxidation States and Unbalanced Reactions

1. Nickel commonly exists in the +2 and +3 oxidation states. If you are given a 1.47g sample of a mixture of the Ni(II) and Ni(III) salts; determine the % by weight of Ni(II) in the mixture if it required 20.31 mL of .050M KMnO4 to titrate to the end point. The unbalanced reaction is: Ni2+ + MnO4  Ni3+ + Mn2+ (acidi

Effect of aspirin on blood alcohol level

Would it be a good idea for a person to take a couple of aspirin tablets before attending a cocktail party? Explain your reasoning. Response needs to be given in a 200-300 words essay. Include a reference as part of the response.

Quantitative Analysis and Electrochemistry

IX) Given the following information, which of the statements is true? Cu2+(aq) + e- → Cu+(aq) Eº = 0.34V 2 H+(aq) + 2 e- → H2(g) Eº = 0.0V Fe2+(aq) + 2 e- → Fe(s) Eº = - 0.44V Ni(s) → Ni2+(aq) + 2 e- Eº = 0.25V a) Cu+2(aq) is the strongest oxidizing agent b) Cu+2(aq) is the weakest oxi

Ionic Compounds and VSEPR Geometry

Please see the attached file for further details. 9.23 Specify which compound in the following pairs of ionic compounds has the higher lattice energy: (a) KCI or MgO, (b) LiF or LiBr, (c) or NaCl. Explain your choice. See attachment. 9.24 Compare the stability (in the solid state) of the following pairs of compounds:

Electrochemistry Problem: Concentration Cells and the Nernst Equation

The cell shown above is a concentration cell. Both cells contain copper solutions and have copper electrodes. The only driving force for this cell is the difference in the concentration of the copper solutions. The system will react to equalize the concentration of the ions in both cells. Calculate ξ, the electromotive forc

5 Electrochemistry Half-Cell Spontaneity Questions

Please see the attached file for complete questions. Question 1: Using and , calculate and for the following reaction: If this is a spontaneous reaction, will it be spontaneous at all temperatures? Question 2: Give the following battery: and and calculate . If you wanted to reduce your of your battery by

Electrochemistry- Cathodes and Anodes

(there are six procedures with the same questions for each procedure) Procedure 1 LAB: Beaker #1: 150 ml CuSO4 Beaker #2: 150 ml SnCl2 Salt Bridge connects the two beakers electrode in CuSO4 is set to copper electrode in SnCl2 is set to tin volt meter reads .4761 Question: 1. Identify the cathode and anode in

Speed of Reaction vs Number of Collisions Required

1.) Compare two chemical reactions, one requiring simultaneous collision of three molecules and the other requiring a collision between two molecules. Assuming all else is equal, which reaction should be faster? Explain your answer. Can you provide an example? 2.) Why do foods cook faster in a pressure cooker relative to an o

Aluminum : Production and Environmental and Health Concerns

Aluminum is one of the most widely used metals. Aluminum is made by electrolysing aluminum oxide in a solvent called cryolite. Research the electolysis of aluminum and answer the followig questions: a) Identify the products of the anode and cathode half-reactions that occur during the electolysis of aluminum oxide. b) Why is i

Redox Reactions, Oxidation Numbers, Limiting Reagent and Yield Problems

1. One of the steps in the commercial process of converting ammonia to nitric acid is the conversion of NH3 into NO: 4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g) In a certain experiment, 2.25 g of NH3 reacts with 3.75 g of O2. a) Which is the limiting reactant? b) How many grams of NO form? c) How many grams of the excess react

Dilution, Titration and Redox Problems

1. Draw me a beaker for each of the following 3 solutions. Show (label) the particles that exist when 1 particle of each dissolves. You don't have to show the water molecules! H3P04 C12H22011 HCHOO 2. Balance the following redox reaction that occurs in basic solution. NO2- (aq) + Al (s) ---> NH3 (g) + Al02- (aq) 3. Descr

Electrode Potential and Gibbs Free Energy Problems

1. What is the standard electrode potential for the half reaction in which free ferric ion is reduced to elemental Iron? 2. Place the following chemical species in ascending order (in energetic terms) as electron acceptors under standard conditions. Fe3+ (reduced to Fe2+); Zn2+ (reduced to Zn); H+;Ag+;Cu2+ (reduced to Cu+)

Orbitals

For Z=28 which orbital is filled last? Why?

Voltage for a Standard Cell

Using the electrode potentials in appendix C3 of your text, calculate the voltage for a standard cell using the following reaction: H2O2 + MnO2 + H+ → Mn+2 + O2 + H2O

IR Spectroscopy Puzzle

Explain how the information from the IR spectrum will be used to solve this puzzle. There are 2 puzzles; answer that question for each of them. See attached file for full problem description.

Oxidation states of Chromium

Chromium is a metal with many oxidation states, which of the following compounds has chromium in its lowest oxidation state? Cr2O3 Cr2O7^2- MgCr2O3

The Nernst Equation

(See attached file for full problem description) --- The Nernst equation is the most important equation in electrochemistry. It is defined as follows: Where is the standard reduction potential of the reaction is the gas constant is the temperature (in Kelvin) is the number of moles of electrons transferred in

Assigning Oxidation Numbers

I need some aid in assigning oxidation numbers to each element in the following equations and identify the oxidizing and reducing agents: CuO(s) + H2(g) ? Cu(s) + H2O(g)

Oxidation or Reduction

I need some help indicating whether this chemical reaction is an oxidation, reduction or neither: Ag (superscript +) (aq) + Cl (aq)-->AgCl(s)