state function: meaning, definition, pronunciation and examples
C1/C2 (Advanced/Proficient)Formal, Academic, Scientific
Quick answer
What does “state function” mean?
A property of a system that depends only on its current equilibrium state, not on the path taken to reach that state.
Audio
Pronunciation
Definition
Meaning and Definition
A property of a system that depends only on its current equilibrium state, not on the path taken to reach that state; its value is fixed when the state of the system is fixed.
In thermodynamics, a quantity whose change is independent of the process path between initial and final states, such as internal energy, enthalpy, entropy, pressure, volume, and temperature. In mathematics and computer science, it can refer to a function whose output is determined solely by the current state of a system.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage. Spelling follows standard conventions (e.g., 'behaviour' in UK vs. 'behavior' in US in related texts, but 'state function' is spelled identically).
Connotations
Neutral, precise, technical. Universally understood in scientific communities.
Frequency
Equally frequent in UK and US academic/scientific contexts, primarily within physics, chemistry, and engineering.
Grammar
How to Use “state function” in a Sentence
[State function] + [verb: is, depends on, is defined by]The + [state function] + [verb: changes, remains][Verb: Show, Prove] + that + [quantity] + is a state functionVocabulary
Collocations
Examples
Examples of “state function” in a Sentence
noun
British English
- Enthalpy is a state function crucial for analysing constant-pressure processes.
- The experiment demonstrated that the proposed quantity was not a true state function.
American English
- Internal energy is a fundamental state function in thermodynamics.
- Identifying which variables are state functions simplifies the model considerably.
Usage
Meaning in Context
Business
Rare. Might appear metaphorically in strategic discussions: 'Our market share is not a state function of our quarterly spending; it depends on the long-term strategy path.'
Academic
Primary context. Used in thermodynamics, physical chemistry, statistical mechanics, and related engineering courses to describe properties like internal energy (U), enthalpy (H), entropy (S).
Everyday
Extremely rare. Would only be used by someone explaining a scientific concept.
Technical
Core term in thermodynamics. Used in research papers, textbooks, and technical specifications to distinguish from process-dependent quantities like heat transfer or work.
Vocabulary
Synonyms of “state function”
Strong
Neutral
Weak
Vocabulary
Antonyms of “state function”
Watch out
Common Mistakes When Using “state function”
- Confusing state functions (e.g., temperature) with path functions (e.g., work).
- Incorrectly stating that 'heat is a state function'. (It is not).
- Using 'state function' to describe a software function that manages program state (related but different context).
FAQ
Frequently Asked Questions
Very closely related. A state variable is a property that defines the state (e.g., P, V, T). A state function is a property that is a *function* of these state variables (e.g., U(P,V), H(S,P)). In practice, the terms are often used interchangeably for simple properties.
Yes. Your current location's altitude is a state function. It has a specific value. The total uphill climbing you did to get there is a path function—it depends on the exact route you took.
It allows for powerful simplifications in science and engineering. Because the change in a state function is path-independent, you can choose any convenient or hypothetical path between two states to calculate that change, often making complex problems solvable.
No. In this context, 'state' refers to the thermodynamic or system state, defined by a specific set of properties like pressure, volume, and temperature.
A property of a system that depends only on its current equilibrium state, not on the path taken to reach that state.
State function is usually formal, academic, scientific in register.
State function: in British English it is pronounced /steɪt ˈfʌŋkʃən/, and in American English it is pronounced /steɪt ˈfʌŋkʃən/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of your bank balance. It's a STATE FUNCTION: its value right now (the state) is $X. It doesn't matter if you got there by depositing a paycheck in one go or via many small deposits (the path). The work you did to earn that money is a PATH FUNCTION.
Conceptual Metaphor
A DESTINATION ON A MAP. The altitude of a city (state function) is fixed. The distance you traveled or the fuel you used to get there (path functions) depend on your route.
Practice
Quiz
Which of the following is a state function?