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Bond Energy in biology vs physics - lecture, essay question, and grading rubric

This essay question asks students to confront an apparent mismatch in biology vs physics language about bond energy: Does it take energy to break bonds as in physics, or is energy released when bonds are broken as in biology (as in ATP hydrolysis)? Answer: It takes energy to break a bond, but then in a larger chemical reaction where stronger bonds are formed later, energy may be released overall. The grading rubric was developed using 150 student responses to the exam question, offering instructors insight into common student ideas and difficulties with the concept of negative bond energy.

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