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We are doing exp 14 next week.<br>
<br>
I have help files for exp 14 for both pre-lab and post-lab for the
graphs<br>
and report. Please take a look at the following links,<br>
<br>
<a
href="http://chemistry.osu.edu/%7Erzellmer/chem1250/lab/lab_1250.htm"><b>Laboratory</b></a><br>
<br>
<a
href="http://chemistry.osu.edu/%7Erzellmer/chem1250/faq/exp14.txt"><b>Exp
14 - Help for Exp 14</b></a><br>
<br>
<br>
For the first link pay close attention to the volumes you should be
using depending<br>
on what compound you have. You won't know which known compound
until<br>
lab. There are 5 volumes for each compound. These are approx. You
are supposed<br>
to get close to one of these and then hold it there for awhile
(about 30 seconds by<br>
adjusting the flame) and then read the temperature.<br>
<br>
At the help link I've been quite specific about s.f. (especially for
logarithms),<br>
what should be in your discussion section, sample calculations, etc.<br>
<br>
For the calculations you need to calculate the pressure of your
sample in the<br>
syringe. You will use eqn 6 on page on page 97. Often people will
get negative<br>
Ps values. They can NOT be negative. I've discussed this at the
help link. It's<br>
because you used Celsius and not kelvin. Remember,<br>
<br>
KELVIN, KELVIN, KELVIN <br>
<br>
<br>
There is no pre-lab quiz on Carmen.<br>
<br>
<b>HOWEVER, there is an on-line data input prelab at the following
link,</b><br>
<br>
<b><a class="moz-txt-link-freetext"
href="http://undergrad-ed.chemistry.ohio-state.edu/genchem/REPORT/">http://undergrad-ed.chemistry.ohio-state.edu/genchem/REPORT/</a></b><br>
<br>
This is a DIFFERENT site than for exp 5. You need read the
discussion and<br>
data analysis section carefully. Watch the exp 14 video (there's a
link on my<br>
web pages) and then write the procedure. Read my help files (see
the<br>
"Laboratory" link on my class web page). Then do the pre-lab.<br>
<br>
For the pre-lab the data given is supposed to be similar to what you
will obtain<br>
in the lab for your unknown. You are given just 3 temp, vol data
(instead of the<br>
five you will get in lab). You use eqn 6 for this to calculate the
Ps. For the<br>
fourth point that is the boiling pt. You don't use eqn 6 for this.
The vapor pressure<br>
of the sample equals the barometric pressure given in the data
(boiling occurs<br>
when the VP of the liquid equals the prevailing atmospheric,
barometric, pressure).<br>
<br>
You will need to graph the points for the pre-lab and determine the
slope of the<br>
resulting best-fit line (linear fit must be used). The easiest
thing to do would be<br>
use Excel for this while doing the pre-lab.<br>
<br>
The sig. fig. for ln(P) are tricky. It's explained in my help file<br>
for exp 14 (see above link) and another help file I have
specifically<br>
about logs and s.f. I've sent both links out before but here they
are<br>
again. Sig. fig. for logarithms is also explained in Appendix A<br>
of the textbook.<br>
<br>
<a
href="http://chemistry.osu.edu/%7Erzellmer/chem1250/faq/sig_fig_logs.txt"><b>Manipulating
Logs and Sig. Figs.</b></a><br>
<br>
<br>
Dr. Zellmer
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