At the transition temperature, what is the change in entropy expressed as?

The relationship between change in entropy and change in enthalpy during a phase transition at the transition temperature is governed by a fundamental thermodynamic principle. At the transition temperature, the system is in equilibrium between the two phases, and the change in entropy for the transition can be expressed as the ratio of the change in enthalpy to the transition temperature. This is encapsulated in the equation Δ_trsS = Δ_trsH / T_trs.

This formulation is derived from the fundamental definition of entropy in the context of reversible processes, where the change in entropy (ΔS) is equal to the heat exchanged (ΔH) divided by the absolute temperature (T) at which the process occurs. Since the phase transition occurs at a specific transition temperature (T_trs), the equation considers both the heat required for the phase change and the temperature at which this change takes place. This relationship captures the balance between the absorbed or released heat during the transition and the disorder (entropy) associated with that process.

Other options present incorrect relationships that do not align with the principles of thermodynamics regarding phase transitions. For example, option B misrepresents the relationship between enthalpy and entropy. Options C and D introduce additions and subtractions that do not