Why does water temperature stop increasing after reaching its boiling point at a specific pressure?

Question

Why does water temperature remain at 100 degrees Celsius at 1 atmospheric pressure (sea level) despite continued addition of heat after it comes to a boil?

Answer 1

During phase change, you have to keep adding heat to break the intermolecular forces between water molecules (hydrogen bonding), and the temperature does not change until ALL of the water turns into gas. Only then will the addition of heat raise the temperature further.

This is also true when ice melts. If you keep adding heat to ice at 0º C, the temperature will not rise until all of the ice turns into water, then the temperature will start rising again.

Answer 2

The water stays at this same temperature due to a thing called the latent heat of fusion. The water will get no hotter than 100 c until all of it turns into steam. All of the energy you put into the water once it starts boiling all the additional heat goes to turn the water into steam. Once it all turns to steam then the temperature will then rise above 100 C.

Answer 3

It is a physical property of water that it has its boiling point at 100 degrees Celsius and transforms into vapour thereafter.But the vapour( steam) can accept more heat and remain in that state.The close bonding of molecules at solid state is not viable beyond the boiing point. This is linked to the density of the atmosphere. Notice that at high altitudes where the pressure is lower, the boiling point comes down. So if the atmosphere is artificially kept at a higher pressure, theoretically, water can retain its liquid status at temperatures higher than 100Degrees C.

Answer 4

At 100°C, and at atmospheric pressure, the water and its vapour are in 'Equilibrium' i.e. the water is boiling and the molecular bonding is breaking and steam is forming.
In order to completely break ALL of the water's molecular bonding, much more heat is needed.
Until all of the water has converted to steam, all of the heat energy is going into breaking these bonds so the temperature does not change. (Latent heat of Vaporisation).
Addition of heat to the steam after complete vaporisation will superheat the steam to whatever temperature you require.
(Sensible heat).

At higher pressures, the water will remain as water until the temperature is in equilibrium with the pressure and again, the water is boiling. For example, at a pressure of 40atm, water boils at 252°C.

Answer 5

That's a trick question. Technically can water will get hotter than 100°C but it'll be water vapor or steam at that temperature.

All mater is in one of four phases and can change phase when the amount of energy (heat) changes. Traditionally mater changes phase in this order.

solid <> liquid <> gas <> plasma (plasma is almost pure energy, like fire and light)

For water it would look something like this.

ice <> water <> steam <> ??? (don't know what this is called)

It's all water (H20) just in different phases and different temperatures. Different types of mater has different temperatures which it changes states. For example, rocks turn from a solid to a liquid (lava) at a MUCH hotter temperature than water. When Celsius was invented we made it so 100°C would be the temperature for which water turns into gas and 0°C would be the temperature which it turns to a solid.

Answer 6

You can heat water to a higher temperature than its boiling point. You then have superheated water, but it is unstable. See the reference. Under normal circumstances, all of the heat you can add to the water is consumed by the phase transition from liquid to gas, the standard enthalpy of vaporization.

Answer 7

because that is the saturation temperature for that pressure. water will then change phase to vapor. at higher elevations, the water boils at a lower temperature due to the lower pressure. That's why some food manufacturer's have you "boil" some foods longer at higher elevations.

Answer 8

well you have to understand what heat is. What is really happening is thermal energy being transfered. Each rise in a degree of temperature takes energy. For example if you push with a certain force you going to get a certain accerleration. No matter how LONG you apply that force the acceleration is the same. If you increase the force (or the energy in the heat instance) then you will increase the acceleration or temperature.

Answer 9

Well, usually when water it reached it's bioling point it starts to become a gas and dissapeer into the air so it would be hard to keep on getting hotter.