Experiments show that it takes 1656 kJ/mol to break all the bonds in methane (CH4) and 4006 kJ/mol to break all the bonds in propane (C3H8). Based on these data, calculate the average bond enthalpy of the C―C bond.

Consider benzene (C₆H₆) in the gas phase. (a) Write the reaction for breaking all the bonds in C₆H₆(g), and use data in Appendix C to determine the enthalpy change for this reaction. (b) Write a reaction that corresponds to breaking all the carbon–carbon bonds in C₆H₆(g). (c) By combining your answers to parts (a) and (b) and using the average bond enthalpy for C – H from Table 8.4, calculate the average bond enthalpy for the carbon–carbon bonds in C₆H₆(g). (d) Compare your answer from part (c) to the values for
C – C single bonds and C C double bonds in Table 8.4. Is benzene’s C – C bond enthalpy exactly halfway between them? If not, which bond type is more similar to that of benzene, CC single or CC double bonds?

Calculate the bond energy per mole for breaking all the bonds in methane, CH4.