Flashcards on Fundamentals of Thermodynamics
Fundamentals of Thermodynamics: A Student's Guide
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Energy and Work in Thermodynamics
41 cards
Card 1
Question: What is a state function in thermodynamics?
Answer: A function that does not depend on the path by which the system arrived at its present state; it depends only on the final and initial states.
Card 2
Question: What is a path function in thermodynamics?
Answer: A function that depends on the path by which the system arrived at its present state.
Card 3
Question: Write the relationship between change in internal energy (ΔU), heat (q), and work (w).
Answer: ΔU = w + q.
Card 4
Question: How are state functions and non-state functions indicated in the given content (by letter case)?
Answer: State functions use capital letters (e.g., U); non-state (path) functions use lower-case letters (e.g., q, w).
Card 5
Question: When energy is exchanged between a system and the surroundings, in what two forms can it be exchanged?
Answer: As heat (q) or as work (w).
Card 6
Question: If a system absorbs heat from the surroundings, what is the process called?
Answer: Endothermic.
Card 7
Question: If a system releases heat to the surroundings, what is the process called?
Answer: Exothermic.
Card 8
Question: Why is internal energy (U) considered a state function according to the content?
Answer: Because it depends only on the present state (initial and final U) and not on the path taken to reach that state.
Card 9
Question: Are heat (q) and work (w) state functions?
Answer: No — q and w are not state functions; they depend on the process path.
Card 10
Question: Give an example (conceptual) from the content illustrating that U is the same while q and w can differ.
Answer: A battery has the same internal energy whether shorted or used to run a fan, but the amounts of q and w differ in the two cases.