Oscillating chemical reactions (OCRs) have been known
since 1828,
with the Belousov–Zhabotinskii (BZ) reaction the most studied
example. Initially, OCRs were considered to be special cases due to
the small number detected and because the oscillatory behavior did
not seem to agree with the second law of thermodynamics. However,
OCRs have become increasingly important not only in chemistry, but
also in biology as they are the foundation of several significant
phenomena: glycolysis, nerve signal transmission, heartbeats, and
so forth. The BZ reaction has been examined both experimentally and
theoretically. Temporal oscillations appear in both cases, but discrepancies
are found between experimental results and theoretical calculations.
This article addresses the discrepancies by describing (i) a simple,
clear, and inexpensive experimental procedure for carrying out the
reaction and determining the oscillation period and (ii) an innovative
methodology that includes the effect of temperature on the original
model using the Arrhenius equation. The equations resulting from this
approach can easily be solved with the help of MATLAB. In addition,
a user-friendly graphical interface has been developed that highlights
the effects on the oscillating system caused by changes in different
parameters. The effect of the temperature generated during the reaction
is also analyzed. This analysis discloses temperature variations:
a relevant issue that the theoretical model does not envisage. The
exercise is appropriate for upper-level physical chemistry students.