Chapter 18, Problem 69AP

A student looked up the $\Delta {\text{G}}_{\text{f}}^{\text{o}}\text{ , }\Delta {\text{H}}_{\text{f}}^{\text{o}}\text{, and }\Delta {\text{S° values for CO}}_{\text{2}}$, in Appendix 2. Plugging these values into Equation 18.10, the student found that $\Delta G_{\text{f}}^{\text{o}}\ne \Delta H_{\text{f}}^{\text{o}}-T\Delta S°$ at 298 K. What is wrong with this approach?