Charge to conductivity
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This is a question in a problem sheet I have been set. Is it do do with the following equation: Λ=Λ0−ac√Λ=Λ0−ac? Surely charge density is proportional to concentration so therefore molar conductivity would decrease linearly with the square root of concentration (and cc αα charge density?). Also, what is the physical origin of this equation; my lecture notes simply say that the ions interact with each other, is it as simple as that?
The second part to this question asks "Does the actual conductivity decrease?". Presumably by "actual conductivity", he means κκ where κ=Λcκ=Λc. I have no idea about this part so any help would be much appreciated.
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Apr 1 '15 at 19:01
RobChem
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The molar conductivity is the conductivity per mole: if you increase the concentration, you increase the number of charge carriers so the conductivity increases. If the number of ions scaled exactly with concentration of electrolyte, the molar conductivity would be constant. However, the conductivity per ion goes down as the ions don't behave as fully independent charge carriers: they combine, and the rate at which they do so will increase as there are more of them. This behavior results in Kohlrausch's Law (that's the law you stated at the beginning of your question), and it is valid for strong (fully dissociated) electrolytes only.