[beautydodo]

I want to know why the steam is hotter than the hot water?

[justcurious55]

It's all the same molecules, but what happens is as it gets hotter, the molecules spread out. So in order for there to be steam, it has to get so hot that the molecules spread that far apart. And then when it cools, the molecules move closer again and condense back into liquid. Make sense? Did I explain that clearly?

[beautydodo]

Please explain more clear.

[justcurious55]

What part? What's still confusing you?

[Perito]

I want to know why the steam is hotter than the hot water?

At 1 atmosphere of pressure, water is liquid between 0 C and 100 C. At 100 C, it is converted to steam (vapor) by absorbing the latent heat of vaporization. At 100 C, both vapor and liquid co-exist. Above 100 C, it is only steam.

If you were to expose something cold to steam, the steam would cool to 100 C and give up to the cold body, the specific heat of steam. Once it reached 100 C, it would condense and give up to the cold body the specific heat of vaporization (enthalpy of vaporization).

Specific heat capacity, ice: 2.108 kJ/kg-K
Specific heat capacity, water: 4.187 kJ/kg-K
Specific heat capacity, water vapor: 1.996 kJ/-kgK

Enthalpy of vaporization (liquid-vapor) 2257 kJ/kg

There are two things to note. First, the specific heat of water is more than double that of steam. That's because of the hydrogen bonds that are broken when water vaporizes. Second, note how much higher the enthalpy of vaporization is than any of the specific heats. There is a lot of energy in steam! This is the main reason why people say that steam is much hotter than hot water. Steam and water may be at or nearly at the same temperature, but there's a lot of energy in the steam that is not in the water.

[selvarajra]

Mr Perito has explained it very nicely

[justcurious55]

selvarajra, do you see the little agree and disagree buttons under the posts? If you agree, you can click the agree bubble, write a comment, and then that user will get what's called a "greenie." and we all like greenies :) but be careful if you disagree with anyone. The disagree is only to be used for FACTUALLY incorrect advice, not differences of opinion. Hope you enjoy amhd :)

[sandhir]

When steam comes in contact with a person, it converts to water releasing the heat of vapourisation which is 1700 calories per gramme of steam. This heat is released on the person. When hot water falls upon a person, only the latent heat of water is released upon the person. Normally only about 40 calories are realsed per gramme of water.

[sandhir]

When steam comes in contact with a person, it converts to water releasing the heat of vapourisation which is 1700 calories per gramme of steam. This heat is released on the person. When hot water falls upon a person, only the latent heat of water is released upon the person. Normally only about 40 calories are realsed per gramme of water.

[mykel1938]

You people are talking about two different things, heat content and tepm. Saturated steam is only as hot as the water it is made from. If you want it hotter you must superheat it, i.e.. Remove it from contact with the water it was made from and heat it separately. Water boils @212f, as the pressure rises in a boiler, the steam and water get hotter but not different temp.. To cause that to happen you must remove the steam from contact with the water it wsa made from. Google, saturated steam, superheated steam, how boilers work, steam tables (not the kind you find in restaurants).

[kkm80123]

Because heat transfer rate of steam is higher in compare to other any other liquid

[D.Anbunathan]

Water in liquid form exist in the same state up to the temperature of 100 degree. When the heating goes more than 100 it is converted into gaseous form and this can attain little more heat and be in the same form. Hence the vapour is felt hotter than water. It is with no technical words so that many can understand without confusion.