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.