Chemical Education Today
Letters The author’s reply: Dr. Berberan-Santos makes two points in his letter. First, he states that the Szyszkowski equation can be approximated by a linear equation at higher concentrations. This is true. We agree that linearizing the equation is a useful way to estimate an initial value for the parameters. Second, he states that the CMC in Figure 2 does not match the literature value and that in the figure the surface tension decreases continuously after the CMC. We must emphasize that Figure 2 is example data from a single student group and thus does not represent the average student data. Also, while it appears that the surface tension is decreasing, the decrease is not monotonic and is within the precision of our apparatus, as operated by students. We thank Dr. Berberan-Santos for his insightful remarks. Supporting JCE Online Material
http://www.jce.divched.org/Journal/Issues/2009/Apr/abs433_2.html Keywords; Full text (HTML and PDF) John Hagen Department of Chemistry & Biochemistry California Polytechnic State University San Luis Obispo, CA 93407-0402;
[email protected] © Division of Chemical Education • www.JCE.DivCHED.org • Vol. 86 No. 4 April 2009 • Journal of Chemical Education
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