Answer: the option that appears in a heating curve (where the heat added is shown) is the change from solid to liquid (letter C)
Step-by-step explanation:
The question requires us to choose, among the options given, which of the options present parts of a heating curve.
A heating curve presents the relationship between temperature, the state of a substance and the heat added over time.
Considering that the heating curve mentioned by the question only considers the heat gained over time, the possible changes of state are the ones that require heat added to happen. We need to keep in mind that:
- to change from a liquid to a solid, the heat is removed from the substance (temperature decreases);
- to change from a solid to a liquid, the heat is added to the substance (temperature increases);
- to change from a gas to a liquid, the heat is removed from the substance (temperature decreases).
Therefore, the option that appears in a heating curve where the heat added is shown is the change from solid to liquid (letter C).