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On 09/01/2012 08:39 PM, wrote:
<blockquote
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<div style="direction: ltr;font-family: Tahoma;color:
#000000;font-size: 10pt;">Sorry, I know I haven't given you
enough time to answer the last question, but I have another one.
For 9.6, it asks about the de Broglie wavelength. From what I
understood in the book de Broglie related wavelength to momentum
so how are we supposed to solve for the wavelength without
any information about the molecules speed or momentum? It also
asks us to compare the value to the average
distance between oxygen molecules at 1 bar and room temp. Is
that something we look up or should we also be calculating that?</div>
</blockquote>
<br>
I'm assuming you mean 9.7 ....<br>
<br>
Think way back to gen chem and the equation for the average kinetic
energy of a gas.<br>
<br>
E = 3/2 RT <br>
<br>
For a single gas molecule that gets modified to <br>
<br>
E = 3/2 kT<br>
<br>
Then use this information, E=1/2/ mv^2, E=hc/lambda, etc,, to
compute the de Broglie wavelength.<br>
<br>
To compute the the average distance between oxygen molecules at one
bar and room temp, assume that you have a 1 cubic meter vessel. At
1 atm and room temperature, how many oxygen molecules are in this
box (the ideal gas law could help you here).<br>
<br>
Once you have computed the number of gas molecules in the box, take
the cube root of that number -- that takes us from particles/cubic
meter down to particles/meter.<br>
<br>
If I know that there are x particles per meter, then the inverse of
that should be the meters/particle -- or the average distance
between particles.<br>
<br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds@theochem.mercer.edu">pounds@theochem.mercer.edu</a>)
Associate Professor of Chemistry and Computer Science
Mercer University, Macon, GA 31207 (478) 301-5627
</pre>
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