Hess's law of  heat of summatiion is based on law of conservation of energy. It has found
Channel: Doubtnut
Date: 2020-08-02

Hess's law of  heat of summatiion is based on law of conservation of energy. It has found significance in deriving heats of many reactions which either do not take place or if take place, than other side reactions also accompany it. For example heat of reaction for `C+(1)/(2)O_(2) rarr CO` can not be studied directly as it occurs with simultaneous reaction of oxidation of `CO` to `CO_(2)` . Bond energy is referred as heat enthalpy when a bond is broken to produce isolated gaseous atoms. In case of breaking up of bonds between unlike atoms `e.g., C-H` bond in `CH_(4)` , bond energy is referred as avarage bond energy as four `C-H` bonds are broken up.  The heat of fusion for water is `+1.44kcal`. The heat requried to change `27g` ice at `0^(@)C` to water is `:`