MICROSCOPIC OBSERVATION OF SOLID-LIQUID REACTION: A NOVEL LABORATORY APPROACH TO TEACHING RATE OF REACTION
ABSTRACT: The importance of
observation in science and science education has triggered this laboratory
development study that investigated the value of an observation kit as a new
approach to teaching rate of reaction in general chemistry class. The kit
consists of a digital microscope, a “chemical reactor”, and a tailor-made
computer application and was used to video-record a solid-liquid reaction and
to produce a series of two dimensional solid images that indicate the extent of
reaction. The two dimensional image areas were calculated by the computer
application and using the assumption that the image area was directly
proportional to the mass of the solid, a plot of solid mass versus time could
be obtained. These steps have been tested in several solid-liquid reaction
systems, with the reaction of solid magnesium oxide with nitric acid solution
resulting in the best images which were transferable to rate of reaction data,
i.e. a plot of solid MgO mass as a function of time. The plot can be used to
explain rate of reaction concepts including average, instantaneous, and initial
rate. Furthermore, the effect of concentration on reaction rate could also be
explained. This study showed that the observation kit and the generated data
set have the advantage of allowing students to clearly and repeatedly visualise
a solid-liquid reaction and relate this with the concept of rates of reactions.
The observation kit also allows teachers and students to extend its application
into inquiry based experiments.
Author: Agus Setiabudi, Asep
Wahyudin, Galuh Yuliani, Mauro Mocerino
Journal Code: jpkimiagg170034
