Final answer:
A heating curve represents the relationship between heat added and temperature change during phase changes of a substance. It shows how the temperature of a substance changes as heat is added or removed. The curve can be used to determine the melting and boiling points of a substance.
Step-by-step explanation:
A heating curve is a graphical representation of the relationship between heat added and temperature change during phase changes of a substance. It shows how the temperature of a substance changes as heat is added or removed. The heating curve of water, for example, includes phases such as heating of ice, co-existing of solid and liquid at the freezing point, heating of liquid water, co-existing of liquid and gas phases at the boiling point, and heating of steam - the gas phase of water.
One important observation from a heating curve is that during phase changes, the temperature remains constant because all the heat energy goes into breaking or forming the bonds between the molecules. The heating curve can be used to determine the melting and boiling points of a substance, which are represented by horizontal lines or plateaus on the curve. However, it is important to note that substances other than water may have different melting and boiling points.
For example, carbon dioxide sublimes rather than melts at standard pressure, so its heating curve would have only one plateau at the sublimation temperature of CO₂.