Textbook 4E9 Help

[SophiaJenny3I]

Hello everyone! Could someone please walk me through your reasoning for 4E9 in the textbook? I attached a picture below. Thank you!

[Hailey Kang 2K]

Hi! This question is basically asking about the stability of benzene as a resonance structure versus the stability in terms of just double bonds and single bonds. The bond enthalpy for a carbon carbon bond in resonance structures is a different value than a C-C double bond or single bond. The problem is asking you to find what the enthalpy would be if you did 3 double bonds and 3 single bonds, which is 3(348kJ) + 3(612kJ) = 2880kJ, vs. 6 bonds of the resonance bonds, which is 6(518kJ) = 3108kJ. From these values, you can infer the stability of the two structures. All the values can be found in table 4E.1 I believe. Hope this helps!

[SophiaJenny3I]

Thank you so much! This did help :)