Abstract:

Many first year students accepted at universities in South Africa have difficulty with chemistry. Most learning programmes in science require students to pass chemistry at first year level but less than 50% of these pass the subject at their first attempt. Ongoing studies at Tshwane University of Technology (TUT) indicate that the problem starts with the subject at high school (or earlier). At school, chemistry is not offered as a separate subject but only as a component of the subject physical science. More emphasis tends to be given to the physics section of the syllabus, possibly due to a lack of resources, including suitably qualified chemistry teachers.
This research paper investigates the problems students experience with stoichiometric calculations, comparing their actual performance with their confidence. Pre- and post-tuition tests over the past three academic years indicate that this fundamental section of the subject presents a major stumbling block to student success. More than half of the students do not know how to work with subscripts and coefficients in basic chemical equations which jeopardises their calculations from the first step. In addition, many of the students are unable to identify limiting and excess reagents because they simply look at the number of moles and do not really understand mole ratios. Initial studies of 172 students admitted to first year chemistry in January 2009 indicate that while 78% are confident that their stoichiometric calculations are correct, only 38% actually answered correctly. A number of different examples are illustrated and targeted students comments recorded which give insight to the problem.
The results of this study will be of value to all universities, especially in countries such as South Africa, where quality of education has declined during a period of political change.