Presently, in Nigerian secondary schools, many of the chemistry teachers adhere strictly to the teacher expository
method of teaching. This might be partly due to their desire to cover the syllabus and partly to their attitude towards
teaching due to the poor economic situation in the country that does not encourage the average Nigerian teacher in
trying out new methods of teaching because of the perceived costs of the teaching materials. This has led to teachers
not exposing the students to meaningful learning, and this at the same time has made students to perceive Chemistry as
abstract and a very difficult subject to understand.
One aspect of the subject that students have been finding difficult is the mole concept which cut across all aspects of
Chemistry. The chief examiner reports of West African School Certificate Examination have consistently asserts that
students are deficient in the use of mole concept which is the bedrock of stoichiometry in chemistry. Stoichiometry is
the branch of Chemistry and chemical engineering that deals with the quantities of substances that enter into, and are
produced by chemical reactions. Every chemical reaction has its characteristic proportions. The method of obtaining
these from chemical formulae, equations, atomic weights, and molecular weights, and determination of what and
how much is used and produced in chemical processes is the major concern of stoichiometry. Stoichiometry is
viewed as the accounting, or mathematics behind chemistry. (Wikipedia, 2010).