Page 166 - Chemistry eBook

Cooling Curve Chart (Part 2)
The straight horizontal lines show:
1. The substance is changing phases and is
experiencing two phases as it changes. a. BC: gas to liquid (condensing)
b. DE: liquid to solid (freezing)
2. There is NO temperature change and NO kinetic energy change. The line is not moving up in temperature. (It’s sleeping.)
3. Potential energy is low because the substance “gave away” heat/energy.
If the Regents gives you a complete curve chart, you know that the substance is going from solid to liquid to gas (in a heating curve chart) or gas to liquid to solid (in a cooling curve chart). If they only give you a partial curve chart, they will tell you at what phase the chart starts.
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