[Sciencestudent]

I wrote a Chemistry test where the question asked me to draw a potential energy diagram for the condensing of a chemical. So I drew an exothermic potential energy diagram to demonstrate that potential energy decreases as bonds are formed. However, I got a zero on the question because the teacher wanted a heating curve. From what she's taught us, heating curves represent temperature change and a change in kinetic energy. I don't think this a heating curve has anything to do win potential energy. this cost me ten percent. I already talked to her about it but she brushed me off. Can someone please tell me where my teacher is coming from or how to show her that she is wrong?

[thetada]

What bonds did you form in your potential energy curve?

[Sciencestudent]

Steam drops in temperature from 135 degrees to 32.6 degrees. I just showed one drop in potential energy for my diagram. She didn't really teach us on how to do a potential energy diagram except for the one that shows the potential energy for the whole reaction. The heating curve she wanted with temperature as the independent axis was supposed to show a temperature decrease from 135 to 100, a state change at 100 and then a decrease in temperature.

[thetada]

Well, I'd agree with your teacher's description of a heating curve ( as described in your second message). For the potential energy curve, I take it you mean two horizontal lines at different heights to demonstrate the different energy levels of the gaseous and liquid water? if she said one and meant the other, I can appreciate your frustration. When you asked her, were any of your classmates nearby? If so that will have made her more reluctant to admit she's wrong. I'm not saying she is wrong btw. I would print out examples of each kind of diagram, approach her during a quiet moment and lead on a face- saving request like: "i want to know how I misunderstood the question."

[Sciencestudent]

Yes that's exactly what I meant by the potential energy diagram, and yes my classmates were there when I asked her. But thank you very much for your help and I will try to approach my teacher about it next week.. Even though she is kind of terrifying haha