Page 1 of 1

Weak Acids and Bases

Posted: Fri Jan 18, 2019 12:29 pm
by Hanniel U 2B
If there a way we can easily identify weak acids and bases or should we just memorize the most common ones?

Re: Weak Acids and Bases

Posted: Fri Jan 18, 2019 2:02 pm
by Brian Chhoy 4I
Since there are so many more weak acid/bases than there are strong ones, I would suggest memorizing the strong ones instead. Last quarter, Lavelle gave us a run through of how you can easily identify the strong acids. Additionally, most likely the question will at least give you a Kb or a Ka, and from there you can identify if it is strong or weak .

Re: Weak Acids and Bases

Posted: Fri Jan 18, 2019 2:32 pm
by chaggard
Easiest way Dr. Lavelle explains it is if it has a low Ka/Kb value. Most likely all the questions for the test will involve weak acids because we were already tested on strong ones last quarter.

Re: Weak Acids and Bases

Posted: Fri Jan 18, 2019 8:10 pm
by Xinyi Zeng 4C
It will be better if you memorize the common strong acids and bases (and I think that we are supposed to do so), then the rest will usually be weak acids. Some common weak acids are those organic acids like HCOOH, CH3COOH, HNO2; and examples of weak bases are NH3 and amines

Re: Weak Acids and Bases

Posted: Sat Jan 19, 2019 12:41 am
by Rami_Z_AbuQubo_2K
From what I know, if you see that an acid has a really small Ka value, then it will be weak. Same goes for Kb, if it is really small, generally the 10^-3 is a good marker for both, then it will be weaker.

Re: Weak Acids and Bases

Posted: Sat Jan 19, 2019 1:43 am
by Cade Okohira 4K
I was informed that we should just memorize the strong acids and bases, and there are seven common strong acids and eight strong bases, which can be found here: http://www.austincc.edu/chemlab/strongacidbase. If they are anything other than these acids/bases, then we can assume the acid/base is weak and does not dissociate completely.

Re: Weak Acids and Bases

Posted: Sat Jan 19, 2019 3:12 am
by 005113695
I think memorizing the strong acids and bases would be helpful, but if the Ka or Kb is given, you will be able to know if its weak or strong based on how small the number is.

Re: Weak Acids and Bases

Posted: Sat Jan 19, 2019 11:17 pm
by chrisavalos-2L
An easy way that professor Lavelle gave us to help identify weak acids is that they have a Ka that is less than that of 10^-3.