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So in this case you are not having to "calculate" the equilibrium
concentration, you are given it for one component and the initial
concentration for the reactants. Since you know the equilibrium
concentration of the FeSCN2+, you, through the reaction
stoichiometry, know how much of the reactants was consumed to reach
equilibrium. <br>
<br>
We did problems like this when we started equilibrium...<br>
<br>
For a reaction A + B --> AB<br>
<br>
is we started with 1 molar A and 2 molar B with no AB we should
have an ICE table like...<br>
<br>
<table border="1" cellpadding="2" cellspacing="2" width="25%">
<tbody>
<tr>
<td valign="top"><br>
</td>
<td valign="top">A<br>
</td>
<td valign="top">B<br>
</td>
<td valign="top">AB<br>
</td>
</tr>
<tr>
<td valign="top">I<br>
</td>
<td valign="top">1.0<br>
</td>
<td valign="top">2.0<br>
</td>
<td valign="top">0.0<br>
</td>
</tr>
<tr>
<td valign="top">C<br>
</td>
<td valign="top">-x<br>
</td>
<td valign="top">-x<br>
</td>
<td valign="top">+x<br>
</td>
</tr>
<tr>
<td valign="top">E<br>
</td>
<td valign="top">?<br>
</td>
<td valign="top">?<br>
</td>
<td valign="top">.02<br>
</td>
</tr>
</tbody>
</table>
<br>
<br>
Once you determine the value of "x" you should be able to set up the
law of mass action and compute the value of K.<br>
<br>
K = [AB]/( [A][B] )<br>
<br>
Let me know if you need anymore help.<br>
<br>
<br>
On 03/18/13 13:28, wrote:
<blockquote
cite="mid:438E8C1AB08C1143AF623F93B5F2DBA8355AD793@CH1PRD0102MB114.prod.exchangelabs.com"
type="cite">
<pre wrap="">Dr. Pounds,
I am confused on #2 of the prelab assignment. This is the question:
For test tube 3 in part II of the lab it is found that the FeSCN2+ concentration is 0.00001. Calculate all of the equilibrium concentrations and determine the value of K based on the contents of tube 3. Record your answer to three significant figures using scientific notation.
I know I need to use the chemical equatin in the lab report, but I am stuck on the ICE table and the values of Fe3+ and SCN-. Also, how do I find K if I do not have the delta G value?
Thanks,
</pre>
</blockquote>
<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
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