Evaluating Organic Chemistry Labs – Prelab Preparation

There are two extremes of laboratory evaluations (grading): 1) A fill-in-the blanks worksheet that is filled out during the laboratory session and handed in at the end of lab. 2) A formal “journal style” lab report and/or a formal presentation of experimental results. In my view, Sophomore Organic Chemistry offers a transition from one to the other. Coming into Organic Chemistry, students have had various experiences in General Chemistry and General Biology with lab reports ranging from fill-in-the blanks worksheets to simple written lab reports. I have divided the lab assignments into three parts for each experiment. The main features of the prelab assignment are 1) investigating the physical properties, solubility, and safety data for each of the chemicals that they will be using in lab 2) making a flowchart of the laboratory procedure, 3) doing any calculations and predictions that will help them perform the experiment more intelligently, and 4) a safety question that addresses a safety issue that could be encountered in the experiment they are about to do. The overall goal is for the students to come to lab adequately prepared to do the lab efficiently and thoughtfully as opposed to the default setting of coming to lab and reading through the procedure recipe-style without any particular forethought. The prelab is typically worth 6-8 points of the 20 points given for each experiment.

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