Chemistry - Thermochemistry Question with Solution | TestHub

$\Delta H_f^{\circ }\left({\mathrm{Cl}}_2,g\right)=0$ $\Delta H_f^{\circ }$ of elements in their standard state is taken to be zero. ${\mathrm{Cl}}_2$ is gas, ${\mathrm{Br}}_2$ is liquid and ${\mathrm{I}}_2$ is solid at room temperature. Energetics Conceptual, implication of rules/laws III