Why does boiling water in a large pot on a stove have a temperature of 100°C even if it has been boiling for an hour?
The temperature of a liquid is always 100°C.
The temperature of a substance does not change during a phase change.
The temperature of a liquid is always the temperature of the gas above it.
The correct answer is: The temperature of a substance does not change during a phase change.
When water boils, it undergoes a phase change from a liquid to a gas. During this phase change, the temperature of the water remains constant at 100°C (at sea level). This occurs because the heat energy being applied to the water is absorbed and used to break the intermolecular forces that hold the water molecules together. This energy is used to convert the water from a liquid to a gas, rather than increasing the temperature.
Once all the water has transformed into steam, any additional heat energy applied to the system will cause an increase in the temperature of the gas. However, as long as there is still liquid water present, the temperature will remain at 100°C until all the liquid has turned into gas.