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The standard enthalpy of combustion at 25^(@)C of hydrogen, cyclohexene (C_(6)H_(10)) and cyclohexane (C_(6)H_(12)) are -241, -3800 and -3920 kJ/ "mole" respectively. Calculate the heat of hydrogenation of cyclohexene. |
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Answer» Solution :Given that, (i) `H_(2)(g)+(1)/(2)O_(2)(g) to H_(2)O(l),DELTAH=-241 "kJ"` (ii) `C_(6)H_(10)(g)+8(1)/(2)O_(2)(g) to 6CO_(2)(g)+5H_(2)O(l),DeltaH=-3800 "kJ"` (iii) `C_(6)H_(12)(g)+9O_(2)(g) to 6CO_(2)(g)+6H_(2)O(l),DeltaH=-3920"kJ"` We have to calculate `DeltaH` of the reaction, `C_(6)H_(10)(g)+H_(2)(g) to C_(6)H_(12)(g),DeltaH=?` Applying the INSPECTION method, i.e., Eqn.(i)+Eqn.(ii)-Eqn.(iii), we get, `H_(2)(g)+(1)/(2)O_(2)(g)+C_(6)H_(10)(g)+8(1)/(2)O_(2)(g)-C_(6)H_(12)(g)-9O_(2)(g) to H_(2)O(l)+6CO_(2)(g)+5H_(2)O(l)-6CO_(2)(g)-6H_(2)O(l),DeltaH=-241+(-3800)-(-3920)` or `C_(6)H_(10)(g)+H_(2)(g) to C_(6)H_(12)(g),DeltaH=-121 "kJ"` |
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