State Function In Thermodynamic

A state function, function of state, or point function for a thermodynamic system is a mathematical function relating several state variables or state quantities (that describe equilibrium states of the system) that depends only on the current equilibrium thermodynamic state of the system(e.g. gas, liquid, solid, crystal, or emulsion), not the path that the system has taken to reach its current state in thermodynamics of equilibrium. A state function describes the equilibrium states of a system, as well as the system type. Because a state variable is often a state function, the value of the state variable as the state function at an equilibrium state is determined by the values of other state variables at that state. 

What Is State Function Thermodynamic?

A thermodynamic system is described by a set of thermodynamic parameters that are not necessarily independent .The dimension of the state space of the system is the number of parameters required to describe the system (D).Two parameters define any two-dimensional system. In two-dimensional thermodynamic state space, choosing a different set of parameters, such as pressure and volume instead of pressure and temperature, results in a different coordinate system, but is otherwise comparable.  Pressure and temperature can be used to determine volume, temperature and volume may be used to determine pressure, and pressure and volume can be used to determine temperature. The state postulate describes higher-dimensional spaces in a similar way.

In general, a state space is defined by an equation of the type F(P,V,T….=0), where P stands for pressure, T for temperature, V for volume, and the ellipsis stands for other state variables such as particle number N and entropy S.The state space can be depicted as a three-dimensional graph if it is two-dimensional, as in the example above (a surface in three-dimensional space). However, because there are more than three state variables in this situation, the axes’ labels are not unique, and just two independent variables are required to define the state. 

Non-state functions reflect a process in which the state functions change, whereas state functions represent quantities or qualities of a thermodynamic system. The state function PV, for example, is proportional to an ideal gas’s internal energy, but the work W is the amount of energy transferred as the system does work. Internal energy can be identified as a distinct type of energy. The amount of energy that has altered its shape or location is referred to as work.

List Of State Functions

Temperature, pressure and volume–

Temperature (T) is a metric for determining how hot or cold something is. It’s also known as a metric for determining an object’s kinetic energy. The force per unit area is what is meant by pressure. The quantity of space occupied by a substance is known as its volume.

Temperature, pressure, and volume changes are all state functions since they are independent of the path through which they occur.

Internal energy–

Internal energy refers to the total amount of energy contained within a substance or system. Internal energy is a state function because the internal energy of a system is determined by its current state rather than how it arrived at that condition. The change in internal energy (U) is solely dependent on the system’s initial and final states, as well as the intermediate stages.

Enthalpy–

H stands for enthalpy, which is also known as heat content.The sum of the internal energy (U) and pressure volume (PV) energy of a system can be described as the enthalpy of the system under a set of parameters.A state function is enthalpy. As a result, the beginning and final states of the system have no bearing on the change in enthalpy (H).

Entropy–

Entropy (S) is a measure of the system’s unpredictability or disorder. The entropy increases as the randomness increases. Gas>Liquid>Solid is the order of unpredictability or entropy for solids, liquids, and gases. Entropy is affected by the physical state, temperature, volume, and number of particles.

The value of entropy is determined only by the reaction’s initial and ultimate temperatures, volume, and number of particles, and is unaffected by the reaction’s course. Entropy is thus a state function.

Free energy–

The quantity of energy available for useful work is referred to as free energy (G).A state function is the Gibbs free energy. As a result, the change in Gibbs free energy is solely determined by the system’s beginning and final states, not by the path taken to achieve the change. G represents the variation in Gibbs free energy.

Difference Between State Function And Path Function

1-Meaning-

state function is a thermodynamic term for a property whose value is independent of the path taken to arrive at that value.

A path function is a thermodynamic term for a property whose value is determined by the path taken to achieve that value.

2-Alternate Titles

State functions are also known as point functions.

Path functions are also known as process functions.

3-Process

State functions are unaffected by state functions or processes.

The path functions are determined by the path or process.

4-Integration

The state function can be integrated using the beginning and end values of the system’s thermodynamic property.

The path function needs a lot of integrals and integration limitations to incorporate the property.

5-values

Regardless of the number of steps, the value of the state function remains constant.

The route function of a single step process is distinct from the path function of a multiple step process.

6-Examples

Examples include entropy, enthalpy, mass, volume, temperature, and other state functions. Path functions include things like heat and mechanical work.

Conclusion-

The state function and the path function are two types of thermodynamic expressions that describe various thermodynamic features. The essential distinction between state function and path function is that state functions are independent of the path or process, but path functions are dependent on the path. In thermodynamics, state functions are extremely significant.