Practice Exam - Electrochemistry Flashcards
From a voltammogram, the reversable potential is based on what?
average of peak potentials
From a voltammogram, diffusion coefficient is based on what?
from peak current if process is electrochemically reversible, as seen from Iss equation
advantage of steady-state voltammetry
better for determinatoion of diffusion coefficient since mass transport current is uneffected by reversibility
advantage of transient voltammetry
more reliable to measure potential as is unaffected by slow electron transfer kinetics
units of scan rate, v
V s-1
units of A or R (radius)
cm2 and cm
units of diffusion coefficient, D
cm2 s-1
conversion of 1 mM to mol/cm3
1 mM = 10-6 mol/cm3
In bulk electrolysis, why is working electode large in surface area?
faster reaction rate
In bulk electrolysis, why is solution stirred?
increase mass transport rate
In bulk electrolysis, why is two cells needed?
avoid mixing of anodic and cathodic products
In bulk electrolysis, why reference and workign electrodes placed in same cell?
minimise uncompensated resistance effect
equation for charge to current?
Q=It
Q = charge (C), I=current (A), t=seconds
1st generation lgucose sensors
glucose + O2 → (GOx) gluconic acid + H2O2
H2O2 → O2 + 2H+ + 2e-
(electrode)
Or O2 + 4H+ + 4e- → 2H2O (electrode)
2nd generation glucose sensors
2nd generation:
Red ⇌ Ox + e-
(electrode)
Ox + GOx → Red + GOx+
Ox + GOx+ → Red + GOx2+
GOx2+ + glucose → GOx + gluconic acid
