당신은 주제를 찾고 있습니까 “ag agcl she – Electrochemistry Reference Electrodes SHE, Calomel, Ag/AgCl Elektrokimia Elektroda Pembanding“? 다음 카테고리의 웹사이트 ppa.diaochoangduong.vn 에서 귀하의 모든 질문에 답변해 드립니다: https://ppa.diaochoangduong.vn/blog. 바로 아래에서 답을 찾을 수 있습니다. 작성자 shinta kirana 이(가) 작성한 기사에는 조회수 173회 및 좋아요 55개 개의 좋아요가 있습니다.
Table of Contents
ag agcl she 주제에 대한 동영상 보기
여기에서 이 주제에 대한 비디오를 시청하십시오. 주의 깊게 살펴보고 읽고 있는 내용에 대한 피드백을 제공하세요!
d여기에서 Electrochemistry Reference Electrodes SHE, Calomel, Ag/AgCl Elektrokimia Elektroda Pembanding – ag agcl she 주제에 대한 세부정보를 참조하세요
Electrochemistry Reference Electrodes SHE Standard Hydrogen Electrode SCE Saturated Calomel Electrode Hg/Hg2Cl2 Ag/AgCl Electrode
Elektroda Pembanding Elektroda Hidrogen Standar Elektroda Kalomel Hg/Hg2Cl2 Elektroda Ag/AgCl
#electrochemistry
#elektrokimia
#selvolta
#referenceelectrode
#electrode
#elektrodapembanding
#elektroda
#kimia
#chemistry
#redox
ag agcl she 주제에 대한 자세한 내용은 여기를 참조하세요.
Silver chloride electrode – Wikipedia
Standard hydrogen electrode (SHE) · Ag/AgCl/saturated KCl · Ag/AgCl/3.5 mol/kg KCl ; 0.000 · +0.197 · +0.205 ; 0.000 · -1.01 · -0.73.
Source: en.wikipedia.org
Date Published: 10/6/2022
View: 71
Relation Between the SHE and the Internal Ag ∕ AgCl …
Relation Between the SHE and the Internal Ag ∕ AgCl Reference Electrode at High Temperatures. J. Öijerholm2,1, S. Forsberg1, H-P.
Source: iopscience.iop.org
Date Published: 4/30/2022
View: 1343
Convert Potentials to Another Reference Electrode
SHE (Standard Hydrogen). Calomel (Sat’d KCl) … Ag/AgCl (Sat’d KCl). Click Here to Convert … Silver/Silver Sulfate Ag/Ag2SO4, K2SO4 (sat’d).
Source: www.gamry.com
Date Published: 1/18/2022
View: 2520
What is potential verses Standard Hydrogen Electrode (SHE)?
SHE, or it will prove what reference system is used for that electrode. Reference System, Potential vs. SHE (mV). Ag/AgCl – 3 M KCl, +208. Red …
Source: support.hach.com
Date Published: 5/7/2022
View: 3066
PIN ĐIỆN HÓA & THẾ ĐIỆN CỰC CHUẨN ĐỘ THẾ OXY HÓA …
Điện cực hydro chuẩn (SHE) … SHE || Fe2+, Fe3+ (Pt) … (SHE). E(SCE). E(Ag/AgCl). Cu2+ + 2e- ↔ Cu(s) 0.339 V 0.098 V 0.142 V. Fe2+ + 2e- ↔ Fe(s.
Source: www.lhu.edu.vn
Date Published: 8/25/2021
View: 5326
Converting potentials between different reference electrodes
From the table in that link, we can see that the potential of a saturated Ag/AgCl reference electrode is +0.199V vs. SHE and the potential …
Source: ubcchemecar.wordpress.com
Date Published: 7/5/2021
View: 2047
주제와 관련된 이미지 ag agcl she
주제와 관련된 더 많은 사진을 참조하십시오 Electrochemistry Reference Electrodes SHE, Calomel, Ag/AgCl Elektrokimia Elektroda Pembanding. 댓글에서 더 많은 관련 이미지를 보거나 필요한 경우 더 많은 관련 기사를 볼 수 있습니다.
주제에 대한 기사 평가 ag agcl she
- Author: shinta kirana
- Views: 조회수 173회
- Likes: 좋아요 55개
- Date Published: 2021. 11. 19.
- Video Url link: https://www.youtube.com/watch?v=H5ra8iyr-Ec
Silver chloride electrode
Common type of reference electrode in electrochemistry
Ag-AgCl reference electrode
A silver chloride electrode is a type of reference electrode, commonly used in electrochemical measurements. For environmental reasons it has widely replaced the saturated calomel electrode. For example, it is usually the internal reference electrode in pH meters and it is often used as reference in reduction potential measurements. As an example of the latter, the silver chloride electrode is the most commonly used reference electrode for testing cathodic protection corrosion control systems in sea water environments.
The electrode functions as a reversible redox electrode and the equilibrium is between the solid (s) silver metal (Ag (s) ) and its solid salt—silver chloride (AgCl (s) , also called silver(I) chloride) in a chloride solution of a given concentration.
In electrochemical cell notation, the silver chloride electrode is written as, e.g., for an electrolyte solution of KCl 3 M:
Ag ( s ) | AgCl ( s ) | KCl ( 3 M ) {\displaystyle {\ce {{Ag(s)}\ |\ {AgCl(s)}\ |\ KCl\ (3M)}}}
The corresponding half-reactions can be presented as follows:
Ag + + e − ↽ − − ⇀ Ag ( s ) {\displaystyle {\ce {Ag+ + e^- <=> Ag(s)}}} AgCl ( s ) + e − ↽ − − ⇀ Ag ( s ) + Cl − {\displaystyle {\ce {AgCl(s) + e^- <=> Ag(s) + Cl-}}}
or, can be written together:[why?][clarification needed][citation needed]
AgCl ( s ) + Ag ( s ) + e − ↽ − − ⇀ Ag ( s ) + e − + Cl − + Ag + {\displaystyle {\ce {AgCl(s) + Ag(s) + e^- <=> Ag(s) + e^- + Cl^- + Ag+}}}
which can be simplified:
AgCl ( s ) ↽ − − ⇀ Ag + + Cl − {\displaystyle {\ce {AgCl(s) <=> Ag+ + Cl^-}}}
This reaction is a reversible reaction and is characterized by fast electrode kinetics, meaning that a sufficiently high current can be passed through the electrode with 100% efficiency of the redox reaction (anodic oxidation and dissolution of the Ag metal along with cathodic reduction and deposition of the Ag+
ions as Ag metal onto the surface of the Ag wire). The reaction has been proven to obey these equations in solutions of pH values between 0 and 13.5.
The Nernst equation below shows the dependence of the potential of the silver-silver(I) chloride electrode on the activity or effective concentration of chloride-ions:
E = E 0 − R T F ln a Cl − {\displaystyle E=E^{0}-{\frac {RT}{F}}\ln a_{{\ce {Cl-}}}}
The standard electrode potential E0 against standard hydrogen electrode (SHE) is 0.230 V ± 10 mV.[citation needed] The potential is however very sensitive to traces of bromide ions which make it more negative. The more exact standard potential given by an IUPAC review paper is +0.22249 V, with a standard deviation of 0.13 mV at 25 °C.[1]
Applications [ edit ]
Commercial reference electrodes consist of a glass or plastic tube electrode body. The electrode consists of a metallic silver wire (Ag (s) ) coated with a thin layer of silver chloride (AgCl), either physically by dipping the wire in molten silver chloride, chemically by electroplating the wire in concentrated hydrochloric acid (HCl)[2] or electrochemically by oxidising the silver at an anode in a chloride solution.
A porous (or fibrous) filter located at/near the tip of the reference electrode allows to establishing a liquid contact between the solution to be measured and the electrolyte solution in equilibrium with the silver chloride (AgCl) coating the Ag (s) surface. An insulated electrical wire connects the silver rod with the measuring instrument. The voltmeter negative terminal is connected to the test wire.
The electrode body contains potassium chloride to stabilize the silver chloride concentration. When working in seawater, this body can be removed and the chloride concentration is fixed by the stable salinity of seawater. The potential of a silver:silver chloride reference electrode with respect to the standard hydrogen electrode depends on the composition of the electrolyte solution and on temperature.
Notes to this table :
(1) The table data source is NACE International (National Association of Corrosion Engineers),[5] except where a separate reference is given.
(2) E lj is the liquid junction potential between the given electrolyte and a reference electrolyte with a molal activity of chloride of 1 mol/kg.
The electrode has many features making it suitable for use in the field:
Stable potential
Non-toxic components
Simple construction
Inexpensive to manufacture
They are usually manufactured with saturated potassium chloride electrolyte, but can be used with lower concentrations such as 1 mol/kg potassium chloride. As noted above, changing the electrolyte concentration changes the electrode potential. Silver chloride is slightly soluble in strong potassium chloride solutions, so it is sometimes recommended the potassium chloride be saturated with silver chloride to avoid stripping the silver chloride off the silver wire.
Biological electrode systems [ edit ] [6] Tab electrode using silver/silver chloride sensing for electrocardiography (ECG)
Silver chloride electrodes are also used by many applications of biological electrode systems such as biomonitoring sensors as part of electrocardiography (ECG) and electroencephalography (EEG), and in transcutaneous electrical nerve stimulation (TENS) to deliver current. Historically, the electrodes were fabricated from pure silver, or from metals such as tin, nickel, or brass (an alloy of copper and zinc) coated with a thin film of silver. In today’s applications, most biomonitoring electrodes are silver/silver chloride sensors which are fabricated by coating a thin layer of silver on plastic substrates while the outer layer of silver is converted to silver chloride.[7]
The principle of silver/silver chloride sensors operation is the conversion of ion current at the surface of human tissues to electron current to be delivered through an electrical wire to the measurement instrument. An important component of the operation is the electrolyte gel applied between the electrode and the tissues. The gel contains free chloride ions such that the ion charge can be carried through the electrolyte solution. Therefore, the electrolyte solution has the same conductivity for the ion current as the human tissues. When the ion current develops, the metallic silver atoms (Ag (s) ) of the electrode oxidize and it releases Ag+
cations to the solution while the discharged electrons carry the electrical charge through the electrical wire. At the same time, the chloride anions (Cl−
) present in the electrolyte solution travel towards the anode (positively charged electrode) where they are precipitated as silver chloride (AgCl) as they bond with the silver cations (Ag+
) present onto the Ag (s) electrode surface. The reaction allows the ion current to pass from the electrolyte solution to the electrode while the electron current passes through the electrical wire connected to the measuring instrument.[8][9]
When there is an uneven distribution of cations and anions, there will be a small voltage called half-cell potential associated with the current. In the direct current (DC) system that is used by the ECG and EEG instruments, the difference between the half-cell potential and the zero potential is shown as DC offset which is an undesirable characteristic. Silver/silver chloride is a common choice of biological electrodes due to its low half-cell potential of about +222 mV (SHE), low impedance, with a toxicity lower than that of the calomel electrode containing mercury.[8]
Elevated temperature application [ edit ]
When appropriately constructed, the silver chloride electrode can be used up to 300 °C. The standard potential (i.e., the potential when the chloride activity is 1 mol/kg) of the silver chloride electrode is a function of temperature as follows:[10]
Temperature dependence of the standard potential (E0) of the silver/silver chloride electrode Temperature Potential E0 versus SHE
at the same temperature (°C) (Volt) 25 0.22233 60 0.1968 125 0.1330 150 0.1032 175 0.0708 200 0.0348 225 -0.0051 250 -0.054 275 -0.090
Bard et al.[11] give the following correlations for the standard potential of the silver chloride electrode between 0 and 95°C as a function of temperature (where t is temperature in °C):
E 0 ( V ) = 0.23659 − ( 4.8564 × 10 − 4 ) t − ( 3.4205 × 10 − 6 ) t 2 − ( 5.869 × 10 − 9 ) t 3 {\displaystyle E^{0}(V)=0.23659-\left(4.8564\times 10^{-4}\right)t-\left(3.4205\times 10^{-6}\right)t^{2}-\left(5.869\times 10^{-9}\right)t^{3}}
The same source also gives the fit to the high-temperature potential between 25 and 275°C, which reproduces the data in the table above:
E 0 ( V ) = 0.23735 − ( 5.3783 × 10 − 4 ) t − ( 2.3728 × 10 − 6 ) t 2 {\displaystyle E^{0}(V)=0.23735-\left(5.3783\times 10^{-4}\right)t-\left(2.3728\times 10^{-6}\right)t^{2}}
The extrapolation to 300°C gives E 0 ( V ) = − 0.138 V {\displaystyle E^{0}(V)=-0.138\ \mathrm {V} } .
Farmer[12] gives the following correction for the potential of the silver chloride electrode with 0.1 mol/kg KCl solution between 25 and 275°C, accounting for the activity of Cl− at the elevated temperature:
E 0.1 mol / kg KCl ( V ) = 0.23735 − ( 5.3783 × 10 − 4 ) t − ( 2.3728 × 10 − 6 ) t 2 + ( 2.2671 × 10 − 4 ) ( t + 273 ) {\displaystyle E^{0.1\ {\ce {mol/kg\ KCl}}}(V)=0.23735-\left(5.3783\times 10^{-4}\right)t-\left(2.3728\times 10^{-6}\right)t^{2}+\left(2.2671\times 10^{-4}\right)(t+273)}
See also [ edit ]
For use in soil they are usually manufactured with saturated potassium chloride electrolyte, but can be used with lower concentrations such as 1 M potassium chloride. In seawater or chlorinated potable water they are usually directly immersed with no separate electrolyte. As noted above, changing the electrolyte concentration changes the electrode potential. Silver chloride is slightly soluble in strong potassium chloride solutions, so it is sometimes recommended that the potassium chloride be saturated with silver chloride.
Calculator for Converting Potentials to another Reference Electrode Gamry Instruments
Convert Potentials to Another Reference Electrode
Bookmark This Page
Enter the recorded voltage in mV and select the reference electrode used to record it.
Calculator-Converting potentials between reference electrodes
RESOURCES > REF ELECTRODES > CONVERTING POT’LS
This calculator can be used to convert potentials recorded using one reference electrode into potentials reported versus another, more commonly accepted, reference electrode.
To use this calculator, enter the recorded voltage in mV in the top textbox and select the reference electrode used to record it. Next, select the reference electrode you would like it reported against, and then click Convert.
This calculator is based on the values listed elsewhere on this web site. In general, the potentials which include liquid junction potentials have been used.
A description of the math is also available in case the electrodes you desire are not included in this calculator.
Converting potentials between different reference electrodes
In electrochemical experiments, it is not unusual to record the potential of a certain electrochemical system using one reference electrode but convert the data into a potential versus another reference electrode before reporting the results. Here, we show a quick and easy way of converting potentials between reference electrodes.
A table of common reference electrodes and their potentials vs. standard hydrogen electrode (SHE) can be easily found online. For this tutorial, we will use the table from Corrosion Doctors: http://corrosion-doctors.org/Corrosion-Thermodynamics/Reference-Half-Cells.htm
From the table in that link, we can see that the potential of a saturated Ag/AgCl reference electrode is +0.199V vs. SHE and the potential of a 1.0M calomel reference electrode is +0.280V vs. SHE.
For example, if the measured potential of our electrochemical system –0.460V with respect to Ag/AgCl, what is the potential with respect to SHE?
To find the answer, we can apply the following formula:
Where is the measured potential with respect to an Ag/AgCl reference, in this case, -0.460V and is the potential of an Ag/AgCl reference electrode with respect to SHE, which is +0.199V.
Solving for , we get
Now, what is the measured potential with respect to 1.0M calomel?
We apply the same formula:
Solving for , we get
To convert potentials between Ag/AgCl and calomel reference electrodes directly, we can combine both equations:
Solving for , we get
Plugging in the numbers, we can see that the answers are the same:
In general, to convert potentials between 2 reference electrodes, we can do:
Then solve for .
A derivation of this formula is best explained visually:
To find the measured potential vs SHE, we need to find the length of the green line (technically, it’s a vector, pointing left).
Based on the information we have, we can find the green vector by adding the red vector (pointing left, giving it a negative value) and the first grey vector (pointing right, therefore positive). In other words,
Similarly, finding the measured potential vs calomel is the same as finding the blue vector. We can do this by adding the difference of the 2 grey vectors to the red vector.
Some sites may give the potential of the reference electrode relative to NHE, RHE, SCE etc. instead of SHE. As long as the potentials given are with respect to the same electrode, the calculations are not affected.
Check back regularly for more electrochemistry updates!
Written by:
The UBC Chem-E-Car Battery Team
Siang, Tampriye, Andy, William
키워드에 대한 정보 ag agcl she
다음은 Bing에서 ag agcl she 주제에 대한 검색 결과입니다. 필요한 경우 더 읽을 수 있습니다.
이 기사는 인터넷의 다양한 출처에서 편집되었습니다. 이 기사가 유용했기를 바랍니다. 이 기사가 유용하다고 생각되면 공유하십시오. 매우 감사합니다!
사람들이 주제에 대해 자주 검색하는 키워드 Electrochemistry Reference Electrodes SHE, Calomel, Ag/AgCl Elektrokimia Elektroda Pembanding
- 동영상
- 공유
- 카메라폰
- 동영상폰
- 무료
- 올리기
Electrochemistry #Reference #Electrodes #SHE, #Calomel, #Ag/AgCl #Elektrokimia #Elektroda #Pembanding
YouTube에서 ag agcl she 주제의 다른 동영상 보기
주제에 대한 기사를 시청해 주셔서 감사합니다 Electrochemistry Reference Electrodes SHE, Calomel, Ag/AgCl Elektrokimia Elektroda Pembanding | ag agcl she, 이 기사가 유용하다고 생각되면 공유하십시오, 매우 감사합니다.
