Question

Which of the following is not considered a state function, but rather is associated with a process or a flow? E, energy p. pressure T, temperature H, enthalpy q, heat

Answer 1

Any reaction which is a part of study, also called as thermodynamic system, is described by the state in which the reactants and products are present. We always mention the state of the reactants, the temperature and pressure at which they are reacting at. These parameters are not dependent on how they are achieved, i.e independent of the path they followed. Thus Temperature (T), Pressure (P) are called as State functions. The Internal energy (E) and Enthalpy (H) of the system are calculated from the difference between their final and initial values. They do not depend on the path they followed to achieve those values. Hence Enthalpy as well as Energy are State functions.

Path functions are dependent on the flow or process through which they are achieved.

Heat (q) is generated or absorbed depending on the path a reaction takes. If it is an exothermic reaction, heat is liberated, whereas if the reaction is endothermic heat is absorbed by the system. Thus, heat (q) depends on the path followed or the process of the reaction.

Hence, Heat (q) is not a STATE FUNCTION. It is a path function.