<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">On 07/27/2015 03:37 PM, wrote:<br>
</div>
<blockquote
cite="mid:C40B2F181831EF44A88CD73525827803130FFFAE8A@MERCERMAIL.MercerU.local"
type="cite">
<pre wrap="">Dr. Pounds,
I had a question on the calculation of the concentration of [B4O5(OH)4 2-] and [Na].
I understand that we need to use the volume of HCl used and it's molarity, so would it be
M1V1=M2V2
V2= total volume after titration
M2 = concentration of borax
M1= molarity of HCl
V1= volume of HCl
And would [Na] be equal to that of borax?
Thank you,
</pre>
</blockquote>
<br>
Let's make sure that we get this right. It will really help if you
look at the first page of the lab procedures when going through
this.<br>
<br>
<br>
For each of the <img style="vertical-align: middle"
src="cid:part1.08090909.07090801@mercer.edu"
title="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
" alt="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
"> you need to use 2 H+. So the concentration of the <img
style="vertical-align: middle"
src="cid:part1.08090909.07090801@mercer.edu"
title="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
" alt="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
"> is going to be 1/2 the moles of acid used in the titration
divided by the original volume you collected in the test tube (5 ml)<br>
<br>
Now, the Ksp expression is<br>
<br>
Ksp = [Na+]^2 [B4O5(OH)4^2-] = (2x)^2 (x).<br>
<br>
The concentration of the <img style="vertical-align: middle"
src="cid:part1.08090909.07090801@mercer.edu"
title="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
" alt="\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[version=3]{mhchem}
\pagestyle{empty}
\begin{document}
\ce{B_4O_5(OH)4$^{2-}} \end{document}
"> is going to be "x". The concentration of the Na+ is going to
be 2x, and the value of Ksp is going to be 4x^3.<br>
<br>
Got it?<br>
<br>
<br>
When you prepare you plot of lnK vs 1/T, be sure to use KELVIN for
the temperature.<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>
</pre>
</body>
</html>