Given the task definition and input, reply with output. In this task, you are given a sentence in the English language. Your job is to translate the English sentence into the Spanish language.

The thermodynamic magnitude that allows to determine if a closed system at constant temperature and pressure, able to perform only P-V work, is in equilibrium is

La magnitud termodinámica que permite determinar si un sistema cerrado a temperatura y presión constante, capaz de realizar sólo trabajo P-V, está en equilibrio es