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m is the molar conductivity at infinite dilution (or limiting molar conductivity), which can be determined by extrapolation of Λ m as a function of √ c, K is the Kohlrausch coefficient, which depends mainly on the stoichiometry of the specific salt in solution, α is the dissociation degree even for strong concentrated electrolytes,
In practice the molar ionic conductivities are calculated from the measured ion transport numbers and the total molar conductivity. For the cation + = + +, and similarly for the anion. In solutions, where ionic complexation or associaltion are important, two different transport/transference numbers can be defined.
The conductivity of a solution of a strong electrolyte at low concentration follows Kohlrausch's Law: =, where Λ 0 m is known as the limiting molar conductivity, K is an empirical constant, and c is the electrolyte concentration. ("Limiting" here means "at the limit of the infinite dilution".)
Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, relative to the conductivity of pure water at 25 °C.
The molar ionic strength, I, of a solution is a function of the concentration of all ions present in that solution. [3]= = where one half is because we are including both cations and anions, c i is the molar concentration of ion i (M, mol/L), z i is the charge number of that ion, and the sum is taken over all ions in the solution.
The Ostwald law of dilution provides a satisfactory description of the concentration dependence of the conductivity of weak electrolytes like CH 3 COOH and NH 4 OH. [3] [4] The variation of molar conductivity is essentially due to the incomplete dissociation of weak electrolytes into ions.
To calculate this number for electrons, we start with the idea that the total density of conduction-band electrons, , is just adding up the conduction electron density across the different energies in the band, from the bottom of the band to the top of the band .
This continues until the equivalence point is reached, at which one obtains a solution of sodium chloride, NaCl. If more base is added, an increase in conductivity or conductance is observed, since more ions Na + and OH − are being added and the neutralization reaction no longer removes an appreciable amount of H +. Consequently, in the ...