When a rotating disk electrode (RDE) is held at a high enough potential, the rate of the reaction is governed by the diffusion rate, the rate at which the analyte diffuses through the diffusion layer to the electrode. The thickness of this diffusion layer, 8, is calculated as 8 = 1.61 D¹36-1/21/6 where D is the diffusion coefficient (m²/s), v is the kinematic viscosity of the liquid (m²/s), and is the rotation rate (radians/s) of the electrode. Additionally, the current density, J (A/m²), is measured using the Levich equation, J = 0.62nFD2/3¹/2-1/6 Co where n is the number of electrons transferred in the half-reaction, F is the Faraday constant, and Co is the concentration of the electroactive species (mol/m³). Calculate 8, in micrometers, and the current density, J, for the reduction of 0.020 M T1³+ to Tl* at a gold electrode in 1 F HCl at 0.80 V vs. SHE at 2300 rpm, where D = 2.5 x 10-9 m²/s and v= 2.0 x 10-6 m²/s. 8= μm

When a rotating disk electrode (RDE) is held at a high enough potential, the rate of the reaction is governed by the diffusion rate, the rate at which the analyte diffuses through the diffusion layer to the electrode. The thickness of this diffusion layer, 8, is calculated as 8 = 1.61 D¹36-1/21/6 where D is the diffusion coefficient (m²/s), v is the kinematic viscosity of the liquid (m²/s), and is the rotation rate (radians/s) of the electrode. Additionally, the current density, J (A/m²), is measured using the Levich equation, J = 0.62nFD2/3¹/2-1/6 Co where n is the number of electrons transferred in the half-reaction, F is the Faraday constant, and Co is the concentration of the electroactive species (mol/m³). Calculate 8, in micrometers, and the current density, J, for the reduction of 0.020 M T1³+ to Tl* at a gold electrode in 1 F HCl at 0.80 V vs. SHE at 2300 rpm, where D = 2.5 x 10-9 m²/s and v= 2.0 x 10-6 m²/s. 8= μm

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter25: Voltammetry

Section: Chapter Questions

Problem 25.17QAP

See similar textbooks

Similar questions

The data below was obtained with a Cl- ISE to prepare a plot of mV vs. log[Cl-]. Assume the unknown saltwater solution was diluted as in the procedure before being measured. What is the ppm Cl- of the undiluted unknown solution? Cl- Concentration (ppm) Potential (mV) 10 160 100 94 1000 40 Diluted Unknown Saltwater 132
A plot of current (amperes) versus the square root of scan rate (volts/sec) for the ferricyanide/ferrocyanide (n=1) reaction give a slope value of 0.0001257. The electrode diameter is 1.5 mm. The concentration of ferricyanide is 10 mM. Calculate the diffusion coefficient in cm2/sec.
An analyst wants to find out the active surface of his electrode before conducting his analyzes. To do this, he carried out a series of measurements by cyclic voltammetry (CV) using a 1 mM solution of K4Fe(CN)6 dissolved in 0.1M NaCl. He recorded the anodic peak intensity (ip) corresponding to the oxidation of Fe(II) to Fe(III) as a function of the scanning speed (v) of the CV (see table). What is the active surface of the electrode? Data: Fe diffusion coefficient (CN)64-, D = 6.67x10-6 cm2/s Randles-Sevcik equation ip = (2,69x105)n3/2ACD1/2v1/2 rate (v/s) ip (A) 5,00E-02 5,75E-05 1,00E-01 7,68E-05 2,00E-01 9,94E-05 5,00E-01 1,42E-04 1,00E+00 2,07E-04
0.5M HA sample with 0.2 dissociation; It is placed in a conductivity cell with a length of 0.9 cm and an area of 2 cm2 and its conductivity is read as 300 mS. For this purpose;a) Equivalent conductivity of the electrolyte ?b) Boundary equivalent conductivity ?c) Decomposition constant ?
At 0°C and 1 bar, a monolayer of CO adsorbed on 1 g of Fe/Al2O3 catalyst occupies a volume of 4.25 cm3. What is the area of the catalyst? The area per adsorbed particle is 0.165 nm2. Give your answer in m2.
1) Name the applications of glass electrodes in potentiometric measurements (please write correctly and concisely).
3) Name the errors of glass electrodes in potentiometric measurements (please write correctly and concisely).
Provide as many error sources in your calibration of the ion-selective electrode (ISE) as you can.
When the transport of the 0,05moldm' KCI aqueous solution was measured at 25°C using the interfacial transfer method, the interface with the CdCl2 aqueous solution moved by 6.3cm for 30 minutes. The current flowing was 0.0052 A and the cross-sectional area of the tube was 0.15 cm이었다. Find the carrying rate of K+?
A conductivity cell was calibrated using 0.01 M KCl (κ = 1.4087x10-3 S/cm) and the measured resistance was 688 Ω. a. Determine the cell constant (include units). b. Determine the molar conductivity, Λm for a 0.0100 M AgNO3 solution in the same cell with a resistance reading of 777Ω.
Here is a use objective for a chemical analysis to be performed at a drinking water purification plant: “Data and results collected quarterly shall be used to determine whether the concentrations of haloacetates in the treated water demonstrate compliance with the levels set by the Stage 1 Disinfection By-products Rule using Method 552.2” (a specification that sets precision, accuracy, and other requirements). Which one of the following questions best summarizes the meaning of the use objective?(i) Are haloacetate concentrations known within specified precision and accuracy?(ii) Are any haloacetates detectable in the water?(iii) Do any haloacetate concentrations exceed the regulatory limit?