# Degree of dissociation accurately defined

by ElmorshedyDr
Tags: accurately, defined, degree, dissociation
 Share this thread:
 P: 403 Is the degree of dissociation the value of Alpha when the dissociation begins with 1 mole of the solute, or is it alpha when the solute is 1 mole at equilibrium, There isn't a difference since I'm talking about very weak electrolytes but I want to know the accurate answer.
 Admin P: 23,537 Degree of dissociation is a fraction of substance that dissociated, and it doesn't depend on the amount of substance dissolved.
P: 403
 Quote by Borek Degree of dissociation is a fraction of substance that dissociated, and it doesn't depend on the amount of substance dissolved.

It's said on Wikipedia that is the value of dissociated moles per 1 mole,

It is meant one mole at equilibrium or when the dissociation begins with that 1 moles ?

 Admin P: 23,537 Degree of dissociation accurately defined I don't care about what wikipedia says. Degree of dissociation is a fraction of the substance that dissociated. You start with n moles, m moles dissociate, degree of dissociation is m/n.
P: 403
 Quote by Borek I don't care about what wikipedia says. Degree of dissociation is a fraction of the substance that dissociated. You start with n moles, m moles dissociate, degree of dissociation is m/n.

Ok, m/n will give the value of m when n is 1, there's no contradiction
 Admin P: 23,537 No contradiction, but a lousy thinking. Ratio doesn't require referring to the amount of substance.
P: 403
 Quote by Borek No contradiction, but a lousy thinking. Ratio doesn't require referring to the amount of substance.

"n moles" is the number of moles at equilibrium or the number of moles that the dissociation starts with ???
 Sci Advisor P: 3,593 The degree of dissociation can be defined independently of equilibrium. E.g., you could measure it as a function of time after bringing an undissociated substance into a solvent.
Admin
P: 23,537
 Quote by Borek You start with n moles, m moles dissociate
 Quote by ElmorshedyDr "n moles" is the number of moles at equilibrium or the number of moles that the dissociation starts with ???
Perhaps it is time you start paying attention to what you read.
P: 403
 Quote by Borek Perhaps it is time you start paying attention to what you read.

I'm sorry, thanks a lot for you help
 P: 403 I have a question about the ionic product of water How is Kw = [ H ] [ OH ] = 10^-14 mole/ liter derived.
 Admin P: 23,537 It is not derived, it is determined experimentally. Please start new threads for new questions.

 Related Discussions Biology, Chemistry & Other Homework 3 Chemistry 2 Biology, Chemistry & Other Homework 6 Differential Equations 4 Biology, Chemistry & Other Homework 1