thermodynamic state
Let an agent explain thermodynamic states and state variables, relay equilibrium, standard and steady-state concepts from thermodynamics references, describe how states are represented and used, and distinguish thermodynamic state from microstate, phase, process and the everyday sense of state.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain thermodynamic states and state variables, relay equilibrium, standard and steady-state concepts from thermodynamics references, describe how states are represented and used, and distinguish thermodynamic state from microstate, phase, process and the everyday sense of state.
The condition of a thermodynamic system specified by its state variables such as temperature, pressure, volume and composition, including equilibrium states, standard states defined by convention for tabulating thermodynamic data, special states such as saturated vapour in equilibrium with its liquid, and non-equilibrium steady states in which flows persist while properties stay constant; the state determines all thermodynamic properties through equations of state.
What it is for: Not applicable; a physical concept.
It can be explain state variables; relay equilibrium and standard states; describe representation; distinguish related concepts.
Distinguishing features
Defined by state variables
Path-independent functions
Standard conventions
Equilibrium and steady states
What it looks like
Not a visible object; a point on a state diagram.
Physical character
standard pressure: 100 kPa - IUPAC since 1982
state variables for a simple system: 2 count - independent, by the state postulate
saturated vapour: at the vapour pressure note
How it is recognised
Condition specified by state variables
Equilibrium state, standard state, saturated vapour, non-equilibrium steady state
A microstate is a molecular configuration; a phase is a homogeneous region; a process changes states
Related models
is a kind of - in registry terms
is described by - relating variables
is represented on - as points and regions
is contrasted with - which changes the state
In practice
Families and kinds
equilibrium states
standard states for data tabulation
saturated and two-phase states
non-equilibrium steady states
metastable states
Standards and regulation
IUPAC recommendations for standard states
NIST and IAPWS property tables
Failure modes and hazards
Confusing state with process or path
Using outdated standard pressure conventions
Confusing steady state with equilibrium
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What a thermodynamic state is.
Science.
Definition
Definition.
Definition
Definition.
- What is a thermodynamic state, what are state variables and functions, and how does it differ from microstate, phase and process? definition
- Is the question about the concept, a specific kind of state or a calculation? boundary
Kinds
Kinds.
Kinds
Kinds.
- What are equilibrium, standard, saturated vapour and non-equilibrium steady states? definition
- Which entry fits the specific kind? action
Theory Theory.
Science.
Postulate
State postulate.
Postulate
Postulate.
- How many variables fix a state, and what do equations of state say? provenance
- Which references are standard? provenance
Functions
State functions.
Functions
Functions.
- Why are internal energy, enthalpy and entropy state functions, and what follows from path independence? provenance
- Which sources are cited? provenance
Practice Practice.
Practice.
Standard
Standard states and tables.
Standard
Standard.
- How are standard states defined, and how are property tables used? action
- Which entry fits standard state? action
Diagrams
Diagrams.
Diagrams
Diagrams.
- How are states shown on phase, pressure-volume and temperature-entropy diagrams? provenance
- Which entry fits phase diagram? action
Context Beyond equilibrium.
Context.
Steady
Steady states.
Steady
Steady.
- What are non-equilibrium steady states, and how does non-equilibrium thermodynamics treat them? provenance
- Which entry fits non-equilibrium thermodynamics? action
History
History.
History
History.
- How did the concept of state develop in classical thermodynamics? provenance
- Which entry fits the history of thermodynamics? action
What the second pass must settle
- Should standard state and saturated vapour be separate primary entries?
- How should thermodynamics references be linked?
- The registry entry has merged aliases naming specific kinds of state; should they be split off?