GIST in section 13.4 - mistake in answer

[Zellmer, Robert]

There is a mistake in the answer for the GIST problem in section
13.4 involving ppm and ppb.  This is on page 538 (14th ed),
545 (13th ed), 526 (12th ed.), page 542 (11th ed.) in the paper
editions.  The error in the answer appears in the all four editions.

The correct answers are 0.23 ppm and 2.30 x 10^2 ppb.

The question might arise as to what the unit is, g SO2/mL soln
or g SO2/g soln.  The problem states it as 0.00023 g SO2/L soln.
This is the same as 0.00023 g SO2/10^3 mL soln.  Our book
doesn't really cover a mass/vol concentration.  Generally, for
this the unit is g/mL.  Since these are very dilute aqueous solns
there's very little difference (almost none) between g SO2/g soln
or g SO2/mL soln since the density of the solution would be close
to that of pure water (~ 1 g/mL).  It  goes through the same argument
I did in class that 1 ppm is 1 mg solute/kg soln and for these dilute
aqueous solution it corresponds pretty much to 1 mg solute/L soln.
If you simply use this you see you have 0.23 mg SO2/L soln and thus
0.23 ppm.

Dr. Zellmer
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osu.edu/pipermail/cbc-chem1220/attachments/20210830/c925a14a/attachment-0001.html>