Question

how much heat energy is transferred when igm of boiling water at 100 degree celsius condenses to water at 100 degree celsius

Answer 1

When 1g of water vapour at 100 degree celsius gets converted into water at 100 degree celsius, then the amount of energy released is equal to the latent heat of vapourisation of water. it is equal to 2260 joule per gram of water.

Answer 2

1 gram of water vapour in gaseous form  at   100 deg.  C,   condenses to 1 gm of water at 100 deg. C,  Then  the latent heat of  vaporisation is released by the vapour.

This is around 2, 260 Joules/gm.

So 2, 260 Joules.