Weak Acids and Bases

Acidity
Basicity
The Conjugate Seesaw

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Armani Dodson 1A
Posts: 24
Joined: Fri Jul 22, 2016 3:00 am

Weak Acids and Bases

Postby Armani Dodson 1A » Sat Dec 03, 2016 1:40 pm

When we do the ice table and for the reactants at equilibrium, it is usually a value of like (0.2-x).... why are we able to ignore that x value???

Mimi Lec 2H
Posts: 29
Joined: Fri Jul 22, 2016 3:00 am

Re: Weak Acids and Bases

Postby Mimi Lec 2H » Sat Dec 03, 2016 1:44 pm

Because we know it is a weak acid/base, we know that Ka is very small, so we can approximate, and basically set that x equal to 0. I think the rule is if the given Ka is smaller than 10^-4, you can safely approximate.

Joslyn_Santana_2B
Posts: 51
Joined: Wed Sep 21, 2016 2:58 pm

Re: Weak Acids and Bases

Postby Joslyn_Santana_2B » Sat Dec 03, 2016 3:34 pm

It is actually if it's exponent is less than or EQUAL TO -4.

Ex: K_a= 3e^(-4), you can use the short cut to find x.


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