Being able to use representations is a fundamental skill in chemistry. It is important for instructors to make sure that students are proficient in using them in the classroom. Until now, research related to students' use of representations as mainly focused on the knowledge differences between experts vs novices and what misconceptions students have while using representations. This study sought to contribute to that research by investigating which types of representations students use by the way of a web-based assessment which was able to track student representation use, including time spent accessing specific representations within a set of five possibilities.

A two phase research study was used to complete this work. The first phase consisted of developing the initial build of the web-based assessment tool then refining it using usability testing. Twenty-three chemistry students were interviewed regarding the usability of the web-based assessment which led to seven major modifications of the assessment's interface. During the second phase, the web-based assessment was given to 626 general chemistry students across two large Midwestern universities. Results showed the web-based assessment to be an effective method of measurement and that chemistry students seem to be narrow in their choice of representations. Specifically, students used the Lewis structure for the majority of the assessment. This observation points to the importance of the chemistry context in driving student representation use.

In conclusion, this interdisciplinary work offers a new method with which to measure students' use of representations in chemistry while highlighting general chemistry students' tendency to use a limited choice of representations in an assessment setting.