Thermodynamics Laws

Thermodynamics

Laws of Thermodynamics

• Zeroth Law: If two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other.
• First Law (Conservation of Energy): Energy cannot be created or destroyed, only converted from one form to another. ΔE = Q - W
  • ΔE: change in energy
  • Q: heat added to the system
  • W: work done on the system
• Second Law: The total entropy of an isolated system always increases over time. ΔS = ΔQ / T
  • ΔS: change in entropy
  • ΔQ: heat added to the system
  • T: temperature
• Third Law: As the temperature of a system approaches absolute zero, the entropy of the system approaches a minimum value.

Thermodynamic Systems

• Closed System: Energy can be transferred across boundaries, but matter cannot.
• Open System: Both energy and matter can be transferred across boundaries.
• Isolated System: No energy or matter can be transferred across boundaries.

Thermodynamic Processes

• Isothermal Process: Temperature remains constant.
• Adiabatic Process: No heat is transferred between the system and surroundings.
• Isobaric Process: Pressure remains constant.
• Isochoric Process: Volume remains constant.
• Cyclic Process: The system returns to its initial state after a series of changes.

Thermodynamic Properties

• Internal Energy (U): The total energy of a system, including kinetic energy, potential energy, and potential energy associated with the molecular structure.
• Enthalpy (H): A measure of the total energy of a system, including internal energy and the energy associated with the pressure and volume of a system. H = U + pV
• Entropy (S): A measure of the disorder or randomness of a system.
• Free Energy (G): The energy available to do work in a system. G = H - TS

Applications of Thermodynamics

• Heat Engines: Convert thermal energy into mechanical energy.
• Refrigeration: Transfer heat from a colder body to a hotter body.
• Thermodynamic Cycles: A series of processes used to convert energy from one form to another.

Laws of Thermodynamics

• Zeroth Law: Thermal equilibrium is a transitive relation, meaning if two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other.
• First Law (Conservation of Energy): Energy cannot be created or destroyed, only converted from one form to another, represented by the equation ΔE = Q - W, where ΔE is the change in energy, Q is the heat added to the system, and W is the work done on the system.
• Second Law: The total entropy of an isolated system always increases over time, described by the equation ΔS = ΔQ / T, where ΔS is the change in entropy, ΔQ is the heat added to the system, and T is the temperature.
• Third Law: As the temperature of a system approaches absolute zero, the entropy of the system approaches a minimum value.

Thermodynamic Systems

• Closed System: Energy can be transferred across boundaries, but matter cannot be transferred.
• Open System: Both energy and matter can be transferred across boundaries.
• Isolated System: No energy or matter can be transferred across boundaries.

Thermodynamic Processes

• Isothermal Process: Temperature remains constant during the process.
• Adiabatic Process: No heat is transferred between the system and surroundings.
• Isobaric Process: Pressure remains constant during the process.
• Isochoric Process: Volume remains constant during the process.
• Cyclic Process: The system returns to its initial state after a series of changes.

Thermodynamic Properties

• Internal Energy (U): The total energy of a system, including kinetic energy, potential energy, and potential energy associated with the molecular structure.
• Enthalpy (H): A measure of the total energy of a system, including internal energy and the energy associated with the pressure and volume of a system, represented by the equation H = U + pV.
• Entropy (S): A measure of the disorder or randomness of a system.
• Free Energy (G): The energy available to do work in a system, represented by the equation G = H - TS.

Applications of Thermodynamics

• Heat Engines: Devices that convert thermal energy into mechanical energy.
• Refrigeration: The process of transferring heat from a colder body to a hotter body.
• Thermodynamic Cycles: A series of processes used to convert energy from one form to another.

Understanding the laws of thermodynamics, including zeroth, first, and second laws. Learn about energy conservation, entropy, and thermal equilibrium.