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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">There is a mistake in the answer for the GIST problem in section<br>
13.4 involving ppm and ppb. This is on page 538 (14th ed),<br>
545 (13th ed), 526 (12th ed.), page 542 (11th ed.). The error<br>
in the answer appears in the all four editions.<br>
<br>
The correct answers are 0.23 ppm and 2.30 x 10^2 ppb. <br>
<br>
The question might arise as to what the unit is, g SO2/mL soln <br>
or g SO2/g soln. The problem states it as 0.00023 g SO2/L soln.<br>
This is the same as 0.00023 g SO2/10^3 mL soln. Our book<br>
doesn't really cover a mass/vol concentration. Generally, for<br>
this the unit is g/mL. Since these are very dilute aqueous solns <br>
there's very little difference (almost none) between g SO2/g soln<br>
or g SO2/mL soln since the density of the solution would be close<br>
to that of pure water (~ 1 g/mL). It goes through the same argument<br>
I did in class that 1 ppm is 1 mg solute/kg soln and for these dilute<br>
aqueous solution it corresponds pretty much to 1 mg solute/L soln.<br>
If you simply use this you see you have 0.23 mg SO2/L soln and thus<br>
0.23 ppm.<br>
<br>
Dr. Zellmer <o:p></o:p></span></p>
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