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The sum of the transport numbers for all of the ions in solution always equals unity: = The concept and measurement of transport number were introduced by Johann Wilhelm Hittorf in the year 1853. [1] Liquid junction potential can arise from ions in a solution having different ion transport numbers.
A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+.The solvation number, n, determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table.
When such a bridge is used, the ions in the bridge are present in large excess at the junction and they carry almost the whole of the current across the boundary. The efficiency of KCl/NH 4 NO 3 is connected with the fact that in these salts, the transport numbers [clarification needed] of anions and cations are the same.
The rate of ion transport through the channel is very high (often 10 6 ions per second or greater). Ions pass through channels down their electrochemical gradient , which is a function of ion concentration and membrane potential, "downhill", without the input (or help) of metabolic energy (e.g. ATP , co-transport mechanisms, or active transport ...
The number of solvent molecules surrounding each unit of solute is called the hydration number of the solute. A classic example is when water molecules arrange around a metal ion. If the metal ion is a cation, the electronegative oxygen atom of the water molecule would be attracted electrostatically to the positive charge on the metal ion. The ...
Characterization of transport properties requires fabricating a device and measuring its current-voltage characteristics. Devices for transport studies are typically fabricated by thin film deposition or break junctions. The dominant transport mechanism in a measured device can be determined by differential conductance analysis.
For multivalent ions, it is usual to consider the conductivity divided by the equivalent ion concentration in terms of equivalents per litre, where 1 equivalent is the quantity of ions that have the same amount of electric charge as 1 mol of a monovalent ion: 1 / 2 mol Ca 2+, 1 / 2 mol SO 2−
Thermodynamically the flow of substances from one compartment to another can occur in the direction of a concentration or electrochemical gradient or against it. If the exchange of substances occurs in the direction of the gradient, that is, in the direction of decreasing potential, there is no requirement for an input of energy from outside the system; if, however, the transport is against ...