Region of space, enclosed by a boundary.
- Open system: Mass, energy transfer is possible. Aka. control volume.
- Closed system: Energy transfer is possible, mass transfer is not possible
- Isolated system: Energy and mass transfer are not possible
Boundary
Section titled “Boundary”Can be imaginary or physical. Boundary can be flexible.
Surroundings
Section titled “Surroundings”Everything outside the system.
Properties
Section titled “Properties”Aka. point functions. Explains the state of the system. Does not depend on the path taken to reach the state.
Intrinsic properties
Section titled “Intrinsic properties”Do not depend on the size of the system.
Examples:
- temperature
- pressure
- specific heat capacity
Extensive properties
Section titled “Extensive properties”Depend on the size of the system.
Examples:
- mass
- volume
- internal energy
- entropy
- enthalpy
- heat capacity
Specific properties
Section titled “Specific properties”Mass-normalized properties. Intrinsic properties. Prefixed with “specific”. Lowercase alphabets are used to denote these.
Examples:
- specific heat capacity
- specific entropy
- specific enthalpy
- specific volume
- specific internal energy
- specific entropy
- specific enthalpy
- specific heat capacity
An instance of the system. Defined by its properties.
If a system is free from gravitational, magnetic, surface tension effects, etc, only 2 independent properties are needed to define the state.
Thermodynamic equilibrium
Section titled “Thermodynamic equilibrium”A state of a system that experiences no change.
Mechanical, phase, chemical, thermal equilibriums are required for thermodynamic equilibrium.
Thermodynamic process
Section titled “Thermodynamic process”A change in the state of a system.
A thermodynamic cycle is series of thermodynamic processes that returns the system to its initial state.
Isothermal process
Section titled “Isothermal process”Process in which the system temperature remains constant throughout.
Adiabatic process
Section titled “Adiabatic process”Process with no heat transfer.
Isobaric process
Section titled “Isobaric process”System pressure remains constant.
Isochoric process
Section titled “Isochoric process”System volume remains constant.
Polytropic process
Section titled “Polytropic process”System pressure and volume are related by a power law.
Quasi-equilibrium process
Section titled “Quasi-equilibrium process”System is in equilibrium throughout the process.
Reversible process
Section titled “Reversible process”A thermodynamic process that can be reversed without any trace on the system and the surrounding. The process follows the same path, in the opposite direction. Ideal case.
Impossible in the environment because of:
- Turbulance
- Friction
- Heat losses
- Resistance
- Finite temperature difference
Internally reversible process
Section titled “Internally reversible process”A thermodynamic process that can be reversed without any trace on the system only. Weaker version of reverisble process.
Irreversible process
Section titled “Irreversible process”A thermodynamic process that cannot be reversed without any trace on the surrounding.
Isentropic process
Section titled “Isentropic process”Reversible adiaatic process. Entropy doesn’t change.
Steady flow process
Section titled “Steady flow process”A thermodynamic process in which, at any fixed point, they remain the same during the entire process.
Point function
Section titled “Point function”A property that depends only on the state of the system.
Examples:
- temperature
- pressure
- volume
- internal energy
Path function
Section titled “Path function”A property that depends on the specific path taken to reach a particular state.
Examples:
- Heat transfer
- Work transfer
Any boundary transfer that depends on the process history is a path function.
Thermodynamic Cycle
Section titled “Thermodynamic Cycle”A series of thermodynamic processes that returns the system to its initial state.