Textbook problem 4.7(b) [ENDORSED]

[Melinda Luo 2G]

(a) Calculate the work that must be done against the atmosphere for the expansion of the gaseous products in the combustion of at 1 mol C₆H₆(l) at 25°C and 1 bar. (b) Using data in Appendix 2A, calculate the standard enthalpy of the reaction.

For part b, why do we use the standard enthalpy of formation for benzene instead of the standard enthalpy of combustion (since this is a combustion equation)? Also, in which cases would we use the standard enthalpy of combustion?

[Chem_Mod]

We are using the standard enthalpies of formation of the reactants and products to determine the reaction enthalpy.

This particular reaction is the combustion of benzene.

If you were given the standard enthalpy of combustion for benzene, there would be nothing to calculate. :-)

One can use the standard enthalpies of formation of the reactants and products to determine the reaction enthalpy for any reaction.