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<div class="moz-cite-prefix">That was for the molar mass lab....<br>
<br>
<br>
for the freezing point depression lab you know the mass of the
solute (around 25 g) and the mass of the solute (around 3 grams
for the first part. Based on the amount of temperature change (<img
style="vertical-align: middle"
src="cid:part1.05060107.02080008@mercer.edu" alt="$\Delta T$">)
between the pure solution and the one with the solute in it you
can set up the equation..<br>
<br>
<img style="vertical-align: middle"
src="cid:part2.04080804.07080403@mercer.edu" alt="$\Delta T =
k_f m$"><br>
<br>
where <img style="vertical-align: middle"
src="cid:part3.08090406.07040300@mercer.edu" alt="$m$"> is the
molality. The molality is the moles of solute divided by the
kilograms of solvent. <br>
<br>
<img style="vertical-align: middle"
src="cid:part4.04080707.01000601@mercer.edu" alt="$\Delta T =
k_f \frac{n}{\mathrm{mass\ in\ kg\ of\ solvent}}$"><br>
<br>
So plug in <img style="vertical-align: middle"
src="cid:part1.05060107.02080008@mercer.edu" alt="$\Delta T$">,
<img style="vertical-align: middle"
src="cid:part6.09060807.00060005@mercer.edu" alt="$k_f$">, and
the mass in kilograms of solvent to solve for the number of moles.<br>
<br>
Then divide the actual mass of the solute by the moles you just
determined to compute the molar mass.<br>
<br>
<br>
<br>
<br>
On 07/01/14 20:19, Andrew J. Pounds wrote:<br>
</div>
<blockquote cite="mid:53B3502B.3090509@mercer.edu" type="cite">
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<div class="moz-cite-prefix"><br>
<br>
On 07/01/14 20:13, wrote:<br>
</div>
<blockquote
cite="mid:C40B2F181831EF44A88CD73525827803130774D669@MERCERMAIL.MercerU.local"
type="cite">
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charset=UTF-8">
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</div>
<div>Dear Professor, </div>
<div><br>
</div>
<div>I have a question about the one part of the 2nd lab. What
is the molecular weight and how would you calculate the
molecular weight, in terms of this lab? </div>
<div><br>
</div>
<div>I have asked multiple people about it, but they were
confused about it as well. Could you help by any chance? </div>
<div><br>
</div>
<div>Thanks a lot, professor. </div>
<div><br>
</div>
<div>Sincerely, </div>
<div><br>
</div>
<br>
</blockquote>
<br>
You use the P, V, T data from the lab to determine the number of
moles of volitalized liquid in the flask. You then divide the
mass of the liquid after it cooled by the number of moles -- this
should give you the molar mass. Does that help?<br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a moz-do-not-send="true" 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 moz-do-not-send="true" class="moz-txt-link-freetext" href="http://faculty.mercer.edu/pounds_aj">http://faculty.mercer.edu/pounds_aj</a>
</pre>
</blockquote>
<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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