# Questions about the Point Function (Thermodynamics)

• Rahulx084
This is true for any process, whether it is constant volume, constant pressure, or any other type. The first law of thermodynamics states that the change in internal energy is equal to the net heat transfer minus the work done. For a closed adiabatic system, where there is no net heat transfer, the change in internal energy is equal to the work done. This implies that work is a point function, as it only depends on the two end states and not on the path taken between them. However, this does not necessarily mean that work is always a point function for every process, as it can still depend on the path for non-adiabatic systems. In summary, for a closed adiabatic system, the
Rahulx084
We know from first law of thermodynamics for a closed system that ##dE##=##\delta Q## -##\delta W## , my question is that for a closed adiabatic system net heat transfer =0 this mean net change in energy = work done , does that mean for an adiabatic system work done is a point function as energy is a point function? If yes , we know that for a constant volume process heat transfer is equal to change in internal energy,does that mean for every constant pressure process for a closed system heat transfer is a point function?

A point function is, by definition, an entity that is independent of path, and depends only on the two end points. So fixing the path and asking whether something is a point function doesn't make a whole lot of sense (to me).

That means for any process irrespective of its nature work is always going to be path function, Right?

Rahulx084 said:
That means for any process irrespective of its nature work is always going to be path function, Right?
It means that, for any two end states, work is always going to be a path function.

Rahulx084

## 1. What is the point function in thermodynamics?

The point function in thermodynamics refers to a property of a system that is dependent only on the current state of the system, and not on the path taken to reach that state. Examples of point functions include temperature, pressure, and volume.

## 2. How is the point function different from a path function?

A path function in thermodynamics is a property of a system that is dependent on the path taken to reach a certain state. This means that the value of a path function can vary depending on the process used to reach a particular state, while the value of a point function remains constant for a given state.

## 3. Can you give an example of a point function in thermodynamics?

One example of a point function in thermodynamics is internal energy. The internal energy of a system is a point function because it is determined solely by the current state of the system, such as its temperature, volume, and composition, and is independent of the process used to reach that state.

## 4. How are point functions used in thermodynamic calculations?

Point functions are used in thermodynamic calculations to determine the change in a system's state from one equilibrium state to another. This is done by considering the initial and final values of point functions and using thermodynamic equations, such as the first law of thermodynamics, to calculate the change in these properties.

## 5. Are all thermodynamic properties point functions?

No, not all thermodynamic properties are point functions. Some properties, such as work and heat, are path functions because their values depend on the process used to reach a certain state. However, all state variables, such as temperature, pressure, and volume, are point functions.

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