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negligible rule

Posted: Wed Dec 06, 2017 8:37 am
by Jasmine Botello 2F
So when K is small enough, then X can be negligible. Does this apply only to weak acids and bases or any type of reaction?

Re: negligible rule  [ENDORSED]

Posted: Wed Dec 06, 2017 8:51 am
by Chem_Mod
This applies to any equilibrium reaction problem that involves an ICE table process to solve. However, you must also consider your initial concentrations or partial pressures. It is actually the % dissociation of an equilibrium reaction being under 5% which allows you to make the negligible x assumption.

Re: negligible rule

Posted: Thu Dec 07, 2017 3:47 pm
by Ethan Vuong 3G
if we are given an equilibrium constant on a question, is that a good indicator that we are calculating a weak base or acid and therefore eliminate the x?

Re: negligible rule

Posted: Thu Dec 07, 2017 3:52 pm
by Scott Chin_1E
I think first looking at the reactants and products of the problem would be a good indication for whether the problem is a weak acid/base question, especially if they only give you K instead of or .

If they give you or , I think its safe to assume that you are working with weak acids/bases especially since strong acids do not require equilibrium constants because they dissociate fully.