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<div class="moz-cite-prefix">On 07/25/13 22:14, Liza Michael
Klyachkin wrote:<br>
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How do you know when you have to find Kb? Like if it gives you Ka
how would you know if you have to use Ka or use Kw to find Kb? <br>
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<div>On Jul 25, 2013, at 9:57 PM, Andrew J. Pounds wrote:</div>
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Let's say that I have the following equilibrium reaction....<br>
<br>
HCOOH + H<sub>2</sub>O <--> H<sub>3</sub>O+ + COOH<sup>-</sup><br>
<br>
Look on the right -- see the H<sub>3</sub>O<sup>+</sup>? In those
cases I use Ka.<br>
<br>
Now, if I just had COOH<sup>-</sup> in solution (no iniitial HCOOH)
then I would have to write my equilibrium reaction as...<br>
<br>
COOH<sup>-</sup> + H<sub>2</sub>O <--> OH<sup>-</sup> +
HCOOH<br>
<br>
Look on the right -- see the OH<sup>-</sup>? In those cases I used
Kb<br>
<br>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Mercer University, Macon, GA 31207 (478) 301-5627
<a class="moz-txt-link-freetext" href="http://faculty.mercer.edu/pounds_aj">http://faculty.mercer.edu/pounds_aj</a>
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