ICE Table Clarification

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705192887
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Joined: Fri Sep 28, 2018 12:18 am

ICE Table Clarification

Postby 705192887 » Wed Jan 23, 2019 4:49 pm

When using an ICE table to determine equilibrium concentrations, when are we allowed to assume x is negligible for the reactant concentration so that we don't have to deal with the quadratic? Thanks

Julia Go 2L
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Re: ICE Table Clarification

Postby Julia Go 2L » Wed Jan 23, 2019 4:52 pm

We can approximate when the Ka or Kb value is less than 10^-3. A small Ka or Kb value means that the acid or base is very weak so not much is ionized during the reaction, which is why we can approximate when we solve for x.

Heesu_Kim_1F
Posts: 60
Joined: Fri Sep 28, 2018 12:18 am

Re: ICE Table Clarification

Postby Heesu_Kim_1F » Wed Jan 23, 2019 4:53 pm

I think the assumption was that x is negligible when k is equal to or less than 10^-3. To check, if x is less than 5% of initial concentration, then the approximation is valid. Hope this helps!

Raj_Bains_2C
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Re: ICE Table Clarification

Postby Raj_Bains_2C » Wed Jan 23, 2019 5:12 pm

We are allowed to assume this when K is less than 10^-3.

Anmol_cheema_2F
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

Re: ICE Table Clarification

Postby Anmol_cheema_2F » Wed Jan 23, 2019 6:38 pm

When K is less than 10^-3, you can neglect x because it will probably be small enough to where it does not have any significant effect on the calculation.


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