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Syllabus
Advanced Technicians Certificate
Electrochemistry
1. Electrochemical cells and electrode reactions
1.1 Appreciate the components of an electrochemical cell and their characteristics.
1.2 Define fundamental terms used in electrochemistry and the revise the electrochemistry concepts introduced in modules MF1 and MF2.
1.3 Classify the possible types of electrode reaction according to the nature of the electrode, the reactions and the products.
1.4 Appreciate some of the important applications of electrode reactions.
1.5 Identify undesirable electrode reactions.
2. Electrochemical cell reactions
2.1 Appreciate that the cell reaction is a redox process that is the resultant of two simultaneous and balanced electrode reactions proceeding in opposite directions.
2.2 Distinguish between spontaneous (galvanic) and driven (electrolytic) cells.
2.3 Understand the difference between the battery, the corrosion cell and the electroplating cell.
2.4 Appreciate typical anode, cathode and cell reactions taking place in electroplating, anodising and reagent regeneration cells.
2.5 Understand the reasons for using a cell divided by an ion-permeable separator.
2.6 Appreciate some of the applications of galvanic cells, including batteries.
2.7 Understand the meaning of the term 'mixed electrode' and have knowledge of typical electrochemical reactions involved in corrosion, immersion deposition and electroless deposition processes.
3. Electrolytes and their properties
3.1 Define the role of an electrolyte.
3.2 Identify the components of an electrolyte.
3.3 Understand the structure of water and the nature of ionic interactions with it.
3.4 Appreciate the Bronsted-Lowery concept of conjugate acids and bases.
3.5 Understand the term hydrolysis and appreciate its importance in metal finishing.
3.6 Define the terms equilibrium constant ,auto ionisation constant of water, Kw, acid dissociation constant Ka, base dissociation constant, Kb, hydrolysis constant, Kh and the terms pKa and pKb.
3.7 Describe the basis of pH and its measurement.
3.8 Appreciate the importance of electrical and electrolytic conductivity in metal finishing.
3.9 Have knowledge of expressions that define the terms conductance, resistivity, conductivity, electrolytic conductivity and molar electrolytic conductivity.
3.10 Understand the principles and practice of electrical conductivity measurements.
3.11 Appreciate the difference between molar electrical conductivity versus concentration behaviour for strong and weak electrolytes.
3.12 Realise the additive contributions made by molar ionic conductivities to the overall molar electrolytic conductivity for the case of infinitely dilute solutions.
3.13 Relate molar ionic conductivity to the transport number of an ion.
4. Equilibrium Electrochemistry
4.1 Appreciate the importance of electrode potentials in metal finishing.
4.2 Understand the principles behind the measurement of electrode potentials.
4.3 Understand the practical methods for measuring an electrode potential with respect to a reference electrode.
4.4 Appreciate the construction and principles of operation of some common reference electrodes.
4.5 Understand the use of the Nernst equation for calculating an equilibrium electrode potential.
4.6 Appreciate common thermodynamic quantities for electrochemical cell reactions, including the Gibbs Free Energy change, the enthalpy change and the equilibrium constant.
4.7 Appreciate the inter-relationship between (a) deltaG, deltaH, deltaS and deltaT and (b) between deltaG and Ke.
4.8 Appreciate the link between deltaG and the equilibrium cell potential, Ecell, together with that between deltaS and the temperature coefficient of the equilibrium cell potential.
4.9 Appreciate some of the applications of reversible cell potential measurements.
5. The Electrode/Electrolytic Zone
5.1 Appreciate the types of near-electrode layers, their origins and their importance in metal finishing.
5.2 Understand a simple model of the electrical double layer structure (which arise due to charge separation) and the resulting potential versus distance profile.
5.3 Appreciate the types of concentration boundary layers (due to convective diffusion) and the resultant concentration versus distance profile.
5.4 Understand the importance of a velocity boundary layer near an electrode surface (due to connection) and the corresponding velocity versus distance profile.
6. Kinetics of Electrode Processes
6.1 Appreciate the fundamental importance of the Faraday constant.
6.2 Appreciate the quantitative equivalence of the amounts of chemical change and electrical energy described by Faraday's laws of electrolysis.
6.3 Understand expressions for the overall rates of electrode reactions obtained by manipulation of Faraday's laws of electrolysis.
6.4 Understand how to use Faraday's laws in order to calculate rates of electrodeposition and corrosion.
6.5 Appreciate the factors that affect the rate of electrode processes.
6.6 Realise that an overall electrode process involves stages of mass transport of material to (or from) the electrode surface and electron transfer at the electrode surface.
6.7 Appreciate the types of overpotential at an electrode and their origins.
6.8 Appreciate the special position of the equilibrium potential for a single electrode process, where the net current is zero and the Nernst equation applies.
6.9 Realise the importance of kinetic expressions to describe the relationship between the overpotential at an electrode and the current density for reactions that are electron transfer controlled.
6.10 Understand the relationship between the Butler-Volmer equation and its special cases: the cathodic Tafel equation, the anodic Tafel equation and the linear, charge transfer resistance equation.
6.11 Appreciate the importance of mass transport control for various electrode reactions in metal finishing.
6.12 Realise that the limiting current depends upon the relative velocity between the electrode and the electrolyte, together with the electrode geometry and the physical properties of the electrolyte.
6.13 Relate the limiting current to the process conditions for a rotating disc electrode under convective-diffusion conditions.
6.14 Apply Fick's First law of diffusion to an electrode reaction under mass transport control and relate the concentration overpotential to the current density.
6.15 Appreciate that the presence of both electron transfer and mass transfer contributions to the rate of an electrode reaction can be treated as mixed control.
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