ROLE OF PRACTICAL ACTIVITIES IN IMPROVING COLLEGE STUDENTS SKILLS IN STOICHIOMETRY AND BETTER UNDERSTANDING OF THE UNITS OF MEASUREMENTS

Abstract

This paper presents results on improvement of collegestudents’ knowledge of “units of measurements” understanding and theirinter-conversions, and improving their skills in manipulating and understandingchemical calculations through practical experiments on corrosion of fourdifferent steel alloys. The experiments constitute a practical part (1hour/week) of a course on materials and corrosion for second year diplomaprogram in chemical processing. The course includes 3 hours theory as the majorpart. The course introduced learners to the physical andmechanical properties of materials commonly used in the chemical processingindustries. One part of the course examines the factors that promote thecorrosion of these materials when used in industrial processes. Learners alsoexamine a variety of means of controlling and monitoring of corrosion andcorrosion processes in chemical industries. During the academic term winter 2017, 20 students wereenrolled in this course. Due to the limited time allotted to practical session,the practical part of the course was focusing on a long single experiment ofmonitoring corrosion rate of four bars of different steel alloys having thesame surface area, placed in a solution of 3.5 % sodium chloride solution, over8 weeks, by measuring weekly weight loss of each specimen. Students’development of knowledge was monitored by three different theoretical tests,over the period, that involve similar calculations (but not identical) on rustand rate of corrosion. The first two tests were undertaken independent of thefinal results of the practical part with similar questions (but not identical)were given. The third test was undertaken after the students have submittedreports of their results and calculation. In the firsttest, two students only were able to score over 80% of the mark in thecalculation part of the test which consists of two problems; four were able tosolve one problem only scoring about 50%. Fourteen students were unable tosolve any of the two problems. In the second test, four students scored over80% of the mark in the calculation part and 7 students scored around 50%. Therest failed to solve any problem. In the third test 19 students scored over 80%and 1 student scored 50%.     On the units of measurement that required 3conversions, 2 students were able to manipulate all the conversion calculationcorrectly, 5 with two correct conversions, 13 with no correct conversion.  In the second test 8 students were able tomanipulate all conversions correctly (although some included few calculationerror), 4 with two correct conversions and 8 with no correct conversions. Inthe third test 18 students were able to manipulate all conversions correctly, 2students with two correct conversions.