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<div class="moz-cite-prefix">On 04/21/2015 07:10 PM, wrote:<br>
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<p>Could you please explain problem 16.136? How do we find the
initial reaction where phosphorous is burned with oxygen?<br>
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<p>Thank you!!<br>
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<br>
The first two equations on the answer page are the reactions for the
burning of white phosphorous and how white phosphorous reacts with
water to form phosphoric acid. Via the stoichometry, 10.0 g of P4
creates 0.323 moles of phosphoric acid. This is in 500 ml, so the
concentration is doubled to 0.646 M.<br>
<br>
The rest of the problem is just like your notes for diprotic acids.
I calculated H+ for the first equlibration and then the H+ for the
second equilibration and added them together. Since the H+ from the
second equilibration was negligible, I could calculate the pH from
the 0.066 M value.<br>
<br>
<br>
<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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