The effect of wording of questions on student responses to equilibrium problems in chemistry

[摘要] Chemical equilibrium is considered to be one of the most difficult topics in chemistry as it isabstract and dependent on a large amount of pre-knowledge. Various studies have been doneabout the misconceptions high school learners, undergraduate students and even chemistryteachers and lecturers have about the topic. Another problem that has been identified withchemistry in general and chemical equilibrium in particular is the use of language as everydaywords often have a different meaning when used in a scientific context. The focus of thisdissertation is to investigate the effect of wording of questions on student responses whensolving problems concerning chemical equilibrium.A two-part questionnaire was designed to test the student responses on questions involving theapplication of Le Chatelier's principle with changes in temperature and pressure for gaseoussystems, and equilibrium constant calculations. In the first part of the questionnaire the heatinvolved in the reaction was described using the correct scientific terms, as well as descriptionswith everyday words. The change in pressure was described as either a change in pressure or achange in volume. In the second part of the questionnaire the format in which the data forequilibrium constant calculations was given was varied. Interviews were conducted withselected students to determine the reasons for their answers. The questionnaire wasadministered to 201 students in the first year General Chemistry course at the PotchefstroomCampus of the North-West University.It was expected that the wording used to describe the equilibrium system or the change wouldhave an effect on the student responses. The analysis of the results as well as the interviewsconfirmed this expectation. The students fared better when the terms exothermic andendothermic were used, rather than descriptions of heat being released or absorbed. Thestudents also fared better when changes in pressure were given instead of changes in volume.In addition it was found that the students relied on rote-learning rather than a thoroughunderstanding of the concepts involved to solve problems relating to the application of LeChatelier's principle. When calculating the equilibrium constant the students had more difficultywhen the volume needed to calculate the equilibrium concentrations were given in scientificnotation or a different unit. The students also struggled when the amounts of the substancesinvolved was given in different units and some of the students were not able to correctly identifywhether the given amount of substance was used during the course of the reaction orremaining when equilibrium was reached.

[发布机构] North-West University