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Why does a pot of boiling water stay at 100 °C until the water evaporates?
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heat
What's the relationship between heat and temperature?
A pot of boiling water remains at 100 °C because all the additional heat supplied to the system is consumed as latent heat of vaporization.1
During a phase change, such as the transition from liquid water to steam, the temperature of the substance does not increase. Instead, the energy is used to overcome the intermolecular forces holding the liquid molecules together, allowing them to transition into a disordered gaseous state. This energy is carried away by the escaping steam molecules. As long as both liquid water and steam are present and the system is at a constant pressure, the temperature remains fixed at the boiling point until the liquid has completely evaporated.12