part 4 (a) gpt - Flashcards
Q: What is a pure substance in thermodynamics?
A: A pure substance has a fixed chemical composition in all phases, meaning its composition remains the same whether it is solid, liquid, or gas.
Q: Give an example of a pure substance.
A: Water (H2O) is a common example of a pure substance.
Q: What is a phase change?
A: A phase change is the transformation of a substance from one state of matter (solid, liquid, gas) to another due to changes in temperature or pressure.
Q: What is the critical point in thermodynamics?
A: The critical point is a specific combination of temperature and pressure at which the liquid and gas phases of a substance become indistinguishable, forming a supercritical fluid.
Q: What are the three phases of a pure substance?
A: Solid, liquid, and gas (vapor).
Q: What is a supercritical fluid?
A: A supercritical fluid is a highly compressed fluid that exhibits properties of both gases and liquids and is created when a substance’s temperature and pressure exceed its critical point.
Q: What is the triple point of water?
A: The triple point of water is the specific temperature (273.16 K) and pressure (611.7 Pa) where water, ice, and vapor coexist in equilibrium.
Q: What is a P-v diagram used for?
A: A P-v diagram shows the relationship between pressure and specific volume at different temperatures and is used to analyze phase transitions and thermodynamic processes.
Q: What is the significance of property diagrams in thermodynamics?
A: Property diagrams help visualize thermodynamic processes, evaluate work and heat transfer, and analyse phase changes, cycles, and state properties.
Q: How does increasing pressure affect the boiling point of water?
A: Increasing pressure raises the boiling point of water, meaning water boils at higher temperatures under higher pressures.
Q: What is an isotherm?
A: An isotherm is a line or curve on a thermodynamic diagram that represents a process occurring at constant temperature.
Q: What is entropy?
A: Entropy is a measure of the disorder or randomness in a system, representing the amount of energy that is unavailable to do work. It typically increases in irreversible processes and is denoted by the symbol S
Q: What is enthalpy?
A: Enthalpy is a thermodynamic property that represents the total heat content of a system, defined as the internal energy plus the product of pressure and volume. It is denoted by the symbol 𝐻 and is often used in the analysis of heat transfer in processes.
