Electrochemistry Definition and 98 Threads

Homework Statement Change your electric potential readings from a Ag/AgCl system to a RHE (reversible hydrogen electrode) system at pH 7. For example, 0.3 V vs Ag/AgCl and -0.1 V vs Ag/AgCl Homework Equations Ag/AgCl 0.222 Volts RHE 0 - 0.0591*pH Volts The...

Im not that familiar with electrochemistry. You have some liquid solution with some concentration of ions, a reference electrode and a sacrifical electrode. You apply a potential with some feedback to control the potential environment of the liquid in the cell. Roughly? Can you do this...

Homework Statement Calculate the normal potential at 25 °C for the reaction: HA(aq) + e- → A-(aq) + 1/2H2(g) if the dissociation constant of HA is equal to 3.3*10-4 Homework Equations ΔG° = -RTlnK ⇔ -ΔG°/nF = RT/(nF)lnK ⇔ E° = RT/(nF)lnK The Attempt at a Solution Just...

Hi, I am a Chemical Engineer but a novice in electrochemistry; hence the query might sound very basic to everyone. We have an industrial electrochemical process (With Iron anode) and we are conducting a lab experiment to understand what is the effect of electrolyte pH on corrosion rate of...

What I know is Molar conductivity is The conductivity of the elctrolyte divided by its concentration . Can someone please explain the physical significance of this ? Also ionic conductivity depends on concentration, if I dilute the electrolyte the ionic conductivity decreases but Molar...

Homework Statement Pb/Pb2+ and Ag/Ag+ Ni/Ni2+ and Zn/Zn2+ Which one is the anode and cathode? Toward which metal do the electrons flow? The Attempt at a Solution 2Ag2+ + Pb ⇔ 2Ag + Pb2+ Pb is anode and Ag is cathode e- go toward Ag. Zn + Ni2+ ⇔ Zn2+ + Ni Zn is...

Homework Statement Simplified lab procedure: I have 3 wells (from well-plate) one with Cu(NO3)2 and a piece of Cu(s) one with AgNO3 and a small piece of Ag(s) last one with Zn(NO3)2 and a piece of Zn(s) Salt bridges are soaked with KNO3 All of the solutions above have molarity of 0.10M A...

I am currently looking into photocatalytic materials. Now I might be over simplifying this process but it my observation that I am just looking at electrolysis but instead of electricity provided by a battery I am using electron hole pairs to generate a potential to do my splitting. My question...

A Galvanic Cell is given. Write its Anode and Cathode half reactions, complete cell reaction and thus determine if the given is concentration cell. Pt|O_2(1\; atm)|NaO\! H(10^{-3}M)||H_2SO_4(0.5M)|O_2(1\;atm)|Pt I know that at anode, Oxygen will get oxidised, maybe from NaOH solution and...

I have Pt(s)/H2(g)/HBr(aq)/AgBr(s)/Ag(s) The question asks why a liquid junction is not necessary. So I know AgBr is insoluble in water, and AgBr coats the silver metal. I just don't understand why it does not matter that the Br- anions from AgBr mixing with the H+ cations doesn't necessitate...

I am a PhD student and I am trying to decipher what is going on in my system, which consists of a platinum electrode, an electrolyte (varying pH, buffer solution with KCl salt and TRIS buffer), thin SiO2 and Si when low bias is applied to the Pt electrode (0 to 0.5 V) with respect to the Si. I'm...

Homework Statement A galvanic cell consisting of two silver electrodes,one in a saturated solution of AgBr and the other in a saturated solution of Ag2CrO4 is prepared.Calculate the value of Ecell at 298K Given Ksp(AgBr) = 5x10-13 M2 and Ksp(Ag2CrO4)=2.4x10-12M3 Homework Equations to...

Homework Statement Line Notation Fe | Fe^(2+) (0.587) || Cd^(2+) (1.009) | Cd T = 297 K E(cell standard) = .04 V Find the potential when [Fe^(2+) changes by .393 M Work Cd^(2+) + Fe --> Cd + Fe^(2+) Q = [Fe^(2+)] / [Cd^2+] Q= [.587 + .393] / [1.009-.393] The Attempt at a...

Homework Statement I just conducted a lab for pchem where we took electric potential measurements with a volt meter in a solution for the reaction AgCl(s) +1/2 H2 (g) <--> HCl(aq) + Ag(s) We took the measurements using different concentrations of HCl. We were told that the...

Hello everyone, I've been reading up on electrochemistry and trying to make the connection from chemistry theory to what I learned during my time as an undergrad and grad student in electrical engineering and I'm having trouble bridging the gap. I have selected one example from my reference text...

Hi, can someone please tell me what does an expression "to activate the surface" in electrochemistry mean? Brief explanaiton of situation: I am investigating the corrosion resistance of certain metals by means of electrochemical methods. During the grinding of the working electrode...

Homework Statement A current of 10.7 Amps is applied to a 1.30 L solution of 0.550M HBr converting some of the H+ to H2(g), which bubbles out of solution. What is the PH of the solution after 77 minutes. Homework Equations The Attempt at a Solution (10.7 C/s)(1 mol e/96485 C)(2...

Homework Statement Several problems. 1) Balance these oxidation-reduction equations in both acidic and basic conditions. In each equation, underline the oxidizing agent. (I have highlighted them. Remember, the oxidizing agent is the species that is reduced and gains electrons.)...

Homework Statement Calculate the minimum mass of carbon needed to reduce 1.00 kg from sufficient zinc oxide. Homework Equations The Attempt at a Solution I think the equation would be 2 ZnO + C = Zn + CO2 I know the molar mass of C is 12.01, O is 16 and Zn is 65.4 I have been...

Homework Statement Tl+/Tl couple can be prepared by saturating 0.100 M KBr with TlBr and alowing Tl+ ions from the insoluble bromide to equilibrate. This couple was observed to have a potential of -0.443V w.r.t Pb2+/Pb couple in which Pb2+ was 1 M. Ksp of TlBr is ? Given: EoPb2+/Pb =...

Using a very simple set up with high school kids, Zinc Plate *on* Filter paper soaked in ZnSO4 *on* cellophane *on* Filter paper soaked in CuSO4 *on* Copper Plate *in* Petri Dish Copper and zinc plate connected to a speaker. I know the process involved and the equations...

Homework Statement An electrochemical cell is made up of a Pb and an Ag electrode: Ag+ + e --> Ag(s) E = 0.8V Pb2+ + 2e --> Pb(s) E = -0.13V Calculate the Ksp for Ag2SO4(s). "Note that to obtain ions in the right compartment, excess silver sulfate solid was addded and a...

How do you know when a species can be oxidized or reduced my an ion? For ex. Which of the species can be oxidized by H+ and which species can be reduced by H2? Ce4+, Ce3+, Fe2+,Fe3+,Fe, Mg2+,Ni2+,Sn

Hello all this is my problem: Homework Statement I have to determine the concentration of a sodium thiosulfate solution used to titrate a potassium iodate solution. The only variable that is known is the concentration of the potassium iodate solution, 0.01 mol/L. There is 20 mL of 0.01 M...

Homework Statement From the perspective of corrosion...Gold and Copper II are joined together and immersed in a 1Molar HCl solution. What possible half-cell reactions and full cell reactions can occur? Which one is most likely to proceed?Homework Equations Half-cell potentials for Au^{3+} +...

We have been given the task to write a feature article for a magazine such as new scientist on an area of interest within the following fields: -Reduction and oxidation -Electrochemistry -Electrowinning I cannot find anything that interests me and has enough relevant information to start...

Homework Statement Two learners, Wade and Tang are working together on a project. They were asked by their teacher to assemble a galvanic cell that would produce a large enough voltage to light up a 1.5V bulb. They are allowed to use two electrodes, one of which must be a zinc electrode...

Hi, I am using a Wheatstone bridge to measure very low resistances (around 0,2ohms) and my measurements are changing from day to day. If I take the resistance measurement of the same resistor several times, I notice that each measurement will be lower than the next. But the next day, the...

Hi, Just having a little trouble understanding the concept of standard cell potential...what is it exactly? I understand that it is compared to a reference potential of 0 for the reaction 2H+ + 2e- -> H2(g). But what does it mean when a given reaction has positive potential (other than the fact...

Homework Statement I have to calculate the redox potential of this equation: Cr2(SO4)3 + 4K2SO4 + 3J2 +7H2O <=> K2Cr2O7 + 6KJ +7H2SO4 I used the nernst equation to calculate the potentials of 2Cr(3+)+7H2O -> Cr2O7(2-) +14H(+) +6e(-) and I2 +2e(-) ->2J(-) which were -1.42V and 0.51V, all...

Dear subscribers Re: Stability test of reference electrode One of the important properties of reference electrode is its stability during measurements or potential scan. How one can check its stability in a certain electrochemical system? One of the way is to use internal reference...

just wondering. i remember once i had a battery, some change, and my keys in my pocket and eventually i reallized the battery got really really hot. just for the heck of it i tried to get that to happen again and it didnt work. can someone explain why this happenned before? i tried putting a...

Homework Statement For the lead storage battery the overall reaction is: Pb(solid) + PbO2(solid) + 2H+ + 2HSO4- --> 2PbSO4(solid) + 2H2O(liq.) for which standard potential, E°, is 2.04 volts. Calculate E for this battery when the concentration of H2SO4 is 8.1 M, that is both H+ and HSO4- = 8.1...

if you make a battery using only au as both cathode and anode and different concentrations(.0001 and 1) of au+, which would be anode and which would be cathode, what would happen? please illustrate. Any help would be highly appreciated Thank you

Homework Statement Electrochemistry - Nernst Equation Pb2+ + 2 e- → Pb (s) ξo = -0.13 V Ag+ + 1 e- → Ag (s) ξo = 0.80 V What is the voltage, at 298 K, of this voltaic cell starting with the following non-standard concentrations: [Pb2+] (aq) = 0.08 M [Ag+] (aq) = 0.5 M Homework...

my question is in three electrode system: working electrode, Pt counter electrode, and Ag/AgCl reference electrode. for example, Mn2+ + 2 H2O -MnO2 + 4 H+ + 2 e− ( −1.22 V), the deposition of Mno2 will be accomplished on postive potential. Cr3+ +3e- Cr ( −0.74 V), the depsotion of metallic Cr...

Mn2+ + 2 H2O - MnO2 + 4 H+ + 2 e− ( −1.22 V), this reaction is acucurate. the standard potential is negative, then why all the work for the formation of MnO2 need to be done in anodic potential?

I'm very confused with an electrochemistry lab. For the lab, we used Al+3, Cu+2, Fe+3, Zn+2, and KNO3. The setup was wells with all of the solutions in them. We soaked a piece of paper(filter paper) in KNO3 for the reactions, then used the paper as a salt bridge between the solutions of the...

1. Homework Statement Given the following half-reactions: Ce4+ + e− → Ce3+ E° = 1.72 V Fe3+ + e− → Fe2+ E° = 0.771 V A solution is prepared by mixing 7.0 mL of 0.30 M Fe2+ with 8.0 mL of 0.12 M Ce4+. Calculate [Ce4+] in the solution. I've got the potential of a platinum electrode...

What is the different between spontaneous reduction and spontaneous oxidation? For spontaneous reduction you need to have Ecell to be (+), then what about spontaneous oxidation? Thanks.

The question: Balance each of the following skeletal equations by using oxidation and reduction half reactions. All the reactions take place in acidic solution. Identify the oxidizing agent and reducing agent in each reaction. a) Cl2 (g) + S2O32-(aq) --> Cl-(aq)+SO42-(aq) My answer so...

Hey guys, I just did a lab on electrochem but we haven't started learning this in our lectures so I'm not too confident on it. One of the lab question asks us to calculate the expected cell voltage. From reading the textbook, this is what I did: The reaction was 2Ag+ + Cu -> 2Ag + Cu2+ I added...

I conduct an experiment to find the emf of the copper-zinc system . I connect the copper to the positive terminal of the batery and a potentiometer and the zinc plate to the galvanometer.The galvanometer is connected to a jockey . The battery I use is 3V .I touch the jockey to the...

what mass of copper could be electroplated on the cathode in an experiment where an average of 200 mA was passed through the cell for 35 mins? I don't understand the question? how do you figure the mass out? I know that copper is 63.55g/mole but do i mutiple it by 200mA and 35 mins?

hey i seem to be having a lot of trouble qith this question may i get some help? The standard potential of the cell below is + 0.9509 V at 25 oC. Calculate the solubility, normally called s, of AgI (Note: Enter the natural log of s (ln s) as your answer) Ag|AgI(s)|AgI(aq)|Ag i'm using nernst...

I would like to do some research on electrochemistry, seeing as I'm doing a project on PEM Fuel Cells, but where should I start? Do you know any good books? Websites? Contacts? Thanks, Pierre.o:) :smile:

Hello all, As I am preparing for my PhD proficiency exam, I tried to solve some Analytical chemistry problems. and stuck in one. Well, I have attempted to solve this, but have not found enough evidence to study on and solve the problem. What I've done is basicly the following: I am in...

Hi people, I have the following question. Fe2+, Fe3+, Cr2O7(2-) and Cr3+ are contained in a solution in standard states with dilute sulphuric acid. Deduce what happens. I am wondering here what effect the sulphuric acid has, is it simply a catalyst for the reaction in which the Cr2O72- is...