Hess's law of heat of summation 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) toCO 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 average bond energy as four C – H bonds are broken up. Heat of dissociation of CH_(4) and C_(2) H_(6) are 360 and 620 kcal mol^(-1) . The C-C bond energy would be : -

Hess's law of heat of summation is based on law of conservation of ene

1.	Hess's law of heat of summation 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) toCO 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 average bond energy as four C – H bonds are broken up. Heat of dissociation of CH_(4) and C_(2) H_(6) are 360 and 620 kcal mol^(-1) . The C-C bond energy would be : -
Answer» 60 kcal 80 kcal 100 kcal 40 kcal Answer :B