Thermodynamic State

Set of properties or values of thermodynamic system is referred as thermodynamic state. It helps in system reproduction. Thermodynamic state parameters are referred as state variables, thermodynamic variables or state parameters. If one of the thermodynamic variable is fixed it is easy to interpret the other thermodynamic variable. Set of values or properties is purely dependent on the system and it cannot be pre determined. Thermodynamic state defines thermodynamic parameters and its macroscopic behavior. Following are thermodynamic parameters

• Pressure
• Temperature
• Density
• Composition

Thermodynamic parameters are developed independent on any system surroundings or history of system. It specifies characteristics of each thermal equilibrium system. It also defines unique state of system and other related parameters derivation and correlation.

Thermodynamic state function

Change in thermodynamic system is referred as state function. It is also referred as state variable or thermodynamic variables and or state function. Total state of the system is constant inclusive of the transition change state. Changes are measured as exact differential. Thermodynamic state function like enthalpy, internal energy, Helmholtz energy and Gibbs energy are developed on the basis of pressure, temperature, volume, and entropy control.

• Enthalpy: It is correlated with heat function of system. When the system is stabilized by thermodynamic parameters such as pressure, entropy and composition.
• Internal energy: When the system is stabilized by thermodynamic parameters such as volume, composition and entropy.
• Helmholtz energy: When the system is stabilized by thermodynamic parameters such as volume, composition and temperature.
• Gibbs energy: When the system is stabilized by thermodynamic parameters such as composition, temperature and pressure.

Equilibrium State

Ideal condition of system is in stable equilibrium state. Thermodynamic state is dynamic process and complex. The system shall have no effect on external environment to attain stable equilibrium state.

Questions:

• Describe relationship between work and heat.
• What is intensive property?
• What are thermodynamic state functions?
• How the state of system changes?
• What is closed simple system?