Advanced Level Chemistry Students’ Understanding of Stoichiometry: Evidence from Four Schools in Zimbabwe

Abstract

This study surveyed Zimbabwean Advanced Level chemistry students’ understanding of stoichiometry and related concepts.  The methods of exploring students’ understanding consisted of paper and pencil surveys (two-tier multiple-choice items) interviews.  Four schools of the thirteen (13 high schools offering Advanced level chemistry in Masvingo province were purposively sampled.  All the one hundred and three (103) students in the four sampled schools participated in the study.  Simple descriptive statistics was used to analyse data.  Some of the surveyed students revealed some unique misconceptions for stoichiometry and related concepts while other findings were consistent with those from earlier studies conducted in other countries.  Students had difficulty with:  (i) coefficients and subscripts (ii) interpretations of representations in equations and formulae (iii) understanding of molar quantities (iv) comprehension and identification of limiting reagents and (v) solving reaction efficiency problems.  The sources of these difficulties are largely attributed to the lack of understanding of fundamental stoichiometry concepts and meta language of expression.  Further research in unexplored areas such as, the influence of the school factor on the type and complexity of misconceptions is recommended.