In the experiment “How can you measure a reaction enthalpy without going into the lab?” we have students use computational thermochemistry to explore the properties and reaction thermodynamics of hydrofluoropropanes. This guided inquiry lab was developed under the Process Oriented Guided Inquiry Lab Physical Chemistry Laboratory (POGIL-PCL) project. Students are asked to find the “best” replacement for the hydrofluoropropane CFC-227, which has been used in military fire suppression systems. The compound has been known to decompose at high temperatures to produce poisonous HF, resulting in some casualties. Students are asked to choose an alternative compound based upon properties predicted with computational chemistry. The number of possibilities is large enough that a class will have to pool data to make a selection. As part of their study, students are also asked to evaluate calculational methods for speed and accuracy and to cooperatively choose the “best” method for the class’s analysis. The evaluation of methods requires them to compare computational results with experimental values. We will compare different outcomes for the students under different computational setups and examine how the students develop and defend their conclusions.

How can you measure a reaction enthalpy without going into the lab?: Using computational chemistry data to draw a conclusion

254th National Meeting (2017)

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