Strong vs weak acids/bases

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Melody Haratian 2J
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Strong vs weak acids/bases

Postby Melody Haratian 2J » Sun Jan 24, 2021 5:53 pm

For acid/base equilibrium, do we only have to use ice tables to find the concentrations of the acid/base at equilibrium if the acid or base is weak? Why do we not use ICE tables if the acid or base is strong?
Thanks!

Chanel Mao 3D
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Re: Strong vs weak acids/bases

Postby Chanel Mao 3D » Sun Jan 24, 2021 5:55 pm

We need to use ICE tables for weak acids/bases, because weak acids and bases don't completely dissociate and therefore we cannot just assume the concentration of a weak acid or base. Because strong acids and bases completely dissociate, we do not need to use an ICE table to figure out the concentration if everything is dissociated. Hope this helps!

Tobie Jessup 2E
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Re: Strong vs weak acids/bases

Postby Tobie Jessup 2E » Sun Jan 24, 2021 7:37 pm

strong acids and bases completely dissociate in solution, but weak acids and bases do not which is why you need to use ICE tables.

Brandon Gruender 3F
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Re: Strong vs weak acids/bases

Postby Brandon Gruender 3F » Sun Jan 24, 2021 7:38 pm

You would use the ICE table for weak acids/bases because they do not completely dissociate during a reaction, so we have to calculate how much changes using x.

Colin Squire 3B
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Re: Strong vs weak acids/bases

Postby Colin Squire 3B » Sun Jan 24, 2021 7:53 pm

Since strong acids and bases completely dissociate, we know exactly where all of the initial concentration is going. We use ICE tables with the weak acids and bases because the don't completely dissociate and is difficult to determine where the initial concentration ends up. Using the ICE table allows us to track all of these values.

Evelyn Silva 3J
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Re: Strong vs weak acids/bases

Postby Evelyn Silva 3J » Sun Jan 24, 2021 7:55 pm

When we are given a strong acid we know that it is completely dissociated because almost all the HA molecules are deprotonated. This allows us to assume that the molar concentration of H3O+ ions is the same as the initial concentration of the strong acid, so we can just calculate pH without using the ICE table. The same is true for a strong base, so we assume the initial concentration is the same for the OH- ions.

Kelly Tran 1J
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Re: Strong vs weak acids/bases

Postby Kelly Tran 1J » Sun Jan 24, 2021 9:27 pm

Hi! Since strong acids/bases completely dissociate, we can assume that the concentration of H3O+ ions is equal to the concentration of the strong acid, and similarly we can assume that the concentration of OH- ions is equal to the concentration of the strong base. This is why ice tables are not needed for strong acids/bases. On the other hand, for weak acids/bases, you would have to make an ice table to calculate the [H3O+] / [OH-] because weak acids/bases do not completely dissociate. Hope this helps!


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