Robert D. Whitakerl Washington and Lee University Lexington, Virginia
A Kinetics Experiment for the Physical Chemistry Laboratory
This paper describes an experiment in chemical kinetirs in which the absorbance of a reacting species is determined as a function of time. The experiment may easily be completed in one or two three-hour laboratory periods with sufficient information to enable the calculation of the activation energy. The results reported herein were obtained with a Beckman Model DB Spectrophotometer, using silica cells with a thickness of 1 cm. Present address: Department of Chemistry, The University of South Florida, Tampa, Florida. H. M., J. Am. l B n s o ~ o F., , HAYES,J. C. AND NEUMANN, Chem. Soc., 75, 5102-6 (1953).
264
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Journal of Chemical Educafion
Basolo, Hayes, and Neumannz studied the rate of dissociation of the tris-o-phenanthroline nickel(I1) ion in acidic solution. These workers found that the complex ion dissociates in a stepwise fashion: k.
Ni(c-phen)++
+ + o-phen
Nit+
+ o-phen
N i ( ~ - p h e n ) ~d ++ Ni(~-phen)~++0-phen k~
NXc-phen).++ kr
Ni(o-phen)++ ---+
with kl
