The enthalpy at constant pressure is given by which of the following?

Prepare for the ACS Physical Chemistry: Thermochemistry Test with detailed questions, flashcards, hints, and explanations. Get ready to excel in the exam!

The definition of enthalpy at constant pressure is fundamentally tied to the relationship between heat transfer in a system and its state functions. Enthalpy, denoted by H, is defined as the sum of the internal energy U and the product of pressure (p) and volume (V). This is expressed mathematically as H = U + pV.

When considering changes in enthalpy with respect to temperature at constant pressure, the term C_p represents the heat capacity at constant pressure, which is defined as the change in enthalpy per unit change in temperature. This relationship, (∂H/∂T)_p, indicates how the enthalpy changes as temperature changes while pressure remains constant. Thus, it directly describes the thermodynamic behavior of the system under constant pressure conditions.

The statement that ΔH = q_p also points to a critical aspect of enthalpy, as it states that the change in enthalpy (ΔH) is equal to the heat absorbed or released at constant pressure (q_p). However, the question specifically asks about how enthalpy itself is defined and characterized at constant pressure, which aligns more closely with the relationship defined by the heat capacity, C_p.

Hence, defining enthal

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