11) Electrode and oxidation-reduction (or) potentials.
Electrode potential, E, in electrochemistry, according to an IUPAC definition,[1] is the electromotive force of a cell built of two electrodes:
on the left-hand side is the standard hydrogen electrode, and
on the right-hand side is the electrode the potential of which is being defined.
By convention:
ECell = ECathode − EAnode
From the above, for the cell with the standard hydrogen electrode (potential of 0 by convention), one obtains:
ECell = ERight − 0 = EElectrode
The left-right convention is consistent with the international agreement that redox potentials be given for reactions written in the form of reduction half-reactions.
Electrode potential is measured in volts (V).
oxidation-reduction (OR) potentials, Reduction potential (also known as redox potential, oxidation / reduction potential, ORP, pE, ε, or Eh) is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced. Reduction potential is measured in volts (V), or millivolts (mV). Each species has its own intrinsic reduction potential; the more positive the potential, the greater the species' affinity for electrons and tendency to be reduced. ORP is a common measurement for water quality.
the mechanism of their appearance and the dependence on different factors. The measured electrode potential may be either that at equilibrium on the working electrode ("reversible potential"), or a potential with a non-zero net reaction on the working electrode but zero net current ("corrosion potential", "mixed potential"), or a potential with a non-zero net current on the working electrode (like in galvanic corrosion or voltammetry). Reversible potentials can be sometimes converted to the standard electrode potential for a given electroactive species by extrapolation of the measured values to the standard state.
Nernst-Peters' equation for calculating of potential values.
The Nernst equation has a physiological application when used to calculate the potential of an ion of charge z across a membrane.The potential across the cell membrane that exactly opposes net diffusion of a particular ion through the membrane is called the Nernst potential for that ion. As seen above, the magnitude of the Nernst potential is determined by the ratio of the concentrations of that specific ion on the two sides of the membrane. The greater this ratio the greater the tendency for the ion to diffuse in one direction, and therefore the greater the Nernst potential required to prevent the diffusion.
12)Galvanic elements (chemical and concentration): action mechanism and calculation of EMF. The galvanic cell, an electric cell or galvanic element, is named after the Italian physician and naturalist L. Galvani. The galvanic cell refers to a set of electrodes which provide electrical energy by electrochemical reactions. The electrodes (positive elektrode = anode, negative electrode = cathode) are separated by a liquid, paste-like or ion-transporting electrolyte. the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targets to which the drug binds, such as an enzyme or receptor. The cell electromotive force, or cell EMF is the net voltage between the oxidation and reduction half-reactions taking place between two redox half-reactions. Cell EMF is used to determine whether or not the cell is galvanic. This example problem shows how to calculate the cell EMF using standard reduction potentials.
13) Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics. Chemical thermodynamics involves not only laboratory measurements of various thermodynamic properties, but also the application of mathematical methods to the study of chemical questions and the spontaneity of processes.
The structure of chemical thermodynamics is based on the first two laws of thermodynamics. Starting from the first and second laws of thermodynamics, four equations called the "fundamental equations of Gibbs" can be derived. From these four, a multitude of equations, relating the thermodynamic properties of the thermodynamic system can be derived using relatively simple mathematics. This outlines the mathematical framework of chemical thermodynamics. The term closed system refers to a physical system which do not allow certain types of transfers (such as transfer of mass) in or out of the system. The specification of what types of transfers are excluded, is different in different contexts.
An isolated system is a thermodynamic system which is completely enclosed by walls through which can pass neither matter nor energy, though they can move around inside it. Or it is a physical system so far removed from others that it does not interact with them, though it is subject to its own gravity. Usually an isolated system is free from effects of long-range external forces such as gravity. The walls of an isolated thermodynamic system are adiabatic, rigid, and impermeable to matter.
An open system is a system which continuously interacts with its environment or surroundings. The interaction can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept. An open system is contrasted with the concept of an isolated system which exchanges neither energy, matter, nor information with its environment. Open system is also known as constant volume system and flow system.
The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot be created or destroyed. The first law is often formulated by stating that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings. Equivalently, perpetual motion machines of the first kind are impossible.