State functions internal energy

What do you understand about state function?

A state function is defined as a property that tends to describe a specific state that doesn’t depend on the path taken to arrive at this particular state. On the other hand, those functions whose value is dependent upon the path selected to reach between two states are referred to as path functions.

A state function is used to describe the equilibrium condition of a system. Along with this, a state function is also used to describe the number of specific kinds of molecules or atoms that are in liquid, gaseous, or solid states. State functions consist of mass, energy, pressure, temperature, entropy, volume, pressure altitude, chemical composition, particle number, and specific volume.

Internal energy 

Internal energy is defined as the energy that is required to create the system in any mentioned internal state. The internal energy is determined as a difference from a reference zero that is considered by a standard state. The measurement of internal energy can’t take place directly. The SI unit of internal energy is Joule (J). 

Internal energy is considered an extensive property. This means that the magnitude of the energy is dependent upon the value of the substance. 

Internal energy is dependent upon the substance’s amount. Internal energy doesn’t rely on the nature of the procedure through which that state was attained. According to the first law of thermodynamics, when a system goes through the procedure of transformation in the state, it results in a procedure in which only work is included. 

Importance of internal energy

1. The internal energy is dependent upon the quantity of substance. Therefore, internal energy is an extensive property.

2. Transformation within internal energy displays the heat that is evolved or absorbed within a reaction at a temperature or volume that is constant.

3. Any process that involves the evolution of energy change is considered negative. On the other hand, any process that involves absorption of energy change is considered positive.

Features of internal energy

1. The internal energy of any system is considered an extensive property.

2. Internal energy is defined as state property. The transformation in internal energy is defined as independent of the path that is followed.

Amount of internal energy in distinctive substances

Every substance consists of different internal energy. This is dependent upon the behavior of the atoms, bonds that are composed within the substance. Along with this, other factors also play a vital role like pressure, temperature, etc.

For example, one mole of carbon dioxide will contain a different amount of internal energy as compared to one mole of sulfur dioxide, having the same state of pressure as well as temperature.

Therefore, every substance will consist of a distinctive amount of internal energy depending upon different factors such as temperature, pressure, heat, mass, etc. Even if two substances are kept under the same conditions like temperature or pressure, they will still tend to have a different amount of internal energy. 

Conclusion 

A state function is defined as a property that tends to describe a specific state that doesn’t depend on the path taken to arrive at this particular state. A state function is used to describe the equilibrium condition of a system. 

Along with this, a state function is also used to describe the number of specific kinds of molecules or atoms that are in a liquid, gaseous, or solid state. Internal energy is defined as the energy that is required to create the system in any mentioned internal state. The SI unit of internal energy is Joule (J). 

Every substance consists of different internal energy. This is dependent upon the behavior of the atoms, bonds that are composed within the substance. Along with this, other factors also play a vital role like pressure, temperature, etc.