The heat of combustion of ethene gas is 330 Kcal `"mol"^(-1)` calculate `gtc=clt` bond energy (in kcal/mol) assuming that bond energy of C-H bond is 9

Monjur Alahi

The heat of combustion of ethene gas is 330 Kcal `"mol"^(-1)` calculate `gtc=clt` bond energy (in kcal/mol) assuming that bond energy of C-H bond is 93.6 Kcal `"mol"^(-1)`
Given :`DeltaH_f^@` for `CO_2(g) and H_2O(l)` are -94.2 and -61 Kcal `"mol"^(-1)` respectively.Heat of atomisation of carbon and hydrogen are 150 and 51.5 Kcal `"mol"^(-1)` respectively.


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Salim Ahmed Kawsar

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Correct Answer - `B.E_((C=C))=112 Kcal//mol`
`CH_2=CH_2(g)+3O_2(g)to2CO_2(g)+2H_2O(l)`
`:.-330=[2xx(94.2)+2(-61)]-[DeltaH_f^@C_2H_4]:.DeltaH_f^@(C_2H_4)=19.6 Kcal mol^(-1)`
`:. 2C(s)+2H_2(g)toCH_2=CH_2(g),DeltaH_f=19.6`
`because DeltaH_("Reaction")=2DeltaH_("atm" ( C))+4DeltaH_("atm"(H))-4B.E._((C=C))`
19.6=2x150+4x51.5-4x93.6-`B.E._((C=C))`
`B.E._((C=C))=112` Kcal/mol

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