The enthalpy changes for the atomization of methane and ethane are 1648 and \(2820 kJmol ^{-1}\) respectively. The \(C - C\) mean bond dissociation energy in \(kJmol ^{-1}\) is therefore ____________
A. 348 B. \(-348\) C. 1176 D. \(-1176\)
Correct Answer: A
Explanation
Since enthalpy of atomization of methane is known, the \(C - H\) dissociation energy can be obtained. \(4 C - H =1648\) \(C - H =(1648 / 4) kJmol ^{-1}\) \(=412 kJmol -1\) \(6(412)+ C - C =2820\) \(C - C =2820-6(412)\) \(=+348 kJmol -1\)