The temperature grows rapidly because steam has a lower heat capacity than water and most of the vapor has left the pot so there is less material to heat up. Most cooks would remove the pot to prevent damaging it, but let's leave it on the burner to see what happens. The temperature of the vapor within the pot continues to rise . It will increase until the pot, and vapor within it, finally reach the same temperature as the burner . At this point, no more heat will flow and the temperature will remain at a steady state.
Pure compounds have a capacity to absorb heat , and in the process warm up.
Pure compounds boil when they reach a temperature called their boiling point . The temperature then remains constant , even though heat is still being added, until all the liquid is boiled away. While boiling, heat is absorbed, but no temperature increase is observed in the liquid or the vapor. This hidden heat is called latent heat . Once all the liquid is boiled off the temperature of the steam will again increase , until the heat source and the steam are at the same temperature.