Chapter 4, Problem 53P

Interpretation Introduction

Interpretation: Biosynthesis of corticosterone from progesterone takes place in two steps. The value of $\Delta H°$ for each step to be calculated.

Concept introduction: Hess's law states that when the reactants are converted to products the change of enthalpy (i.e. the heat of reaction at constant pressure) does not dependent on the pathway between the initial and final states.

Hess’s law states that enthalpy changes are additive. Thus, for a single reaction.

  $\Delta H°\left(\text{reaction}\right)={\displaystyle \sum \Delta H°f\left(\text{Products}\right)-{\displaystyle \sum \Delta H°f\left(\text{Reactants}\right)}}$