Chemical Engineering Thermodynamics interview questions
27 real Chemical Engineering Thermodynamics questions from the Chemical Core bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Steady-flow energy equation?
Junior
A.degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
B.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
C.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
D.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
A.Steady-flow energy equation — links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
B.Steady-flow energy equation — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
C.Steady-flow energy equation — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
D.Steady-flow energy equation — effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
A.Gibbs phase rule — degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
B.Gibbs phase rule — difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation
C.Gibbs phase rule — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
D.Gibbs phase rule — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
8. Which term means: "effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas"?
14. Which term means: "correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC"?
A.Activity coefficient — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
B.Activity coefficient — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
C.Activity coefficient — links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
D.Activity coefficient — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
17. Which term means: "links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume"?
A.Clausius-Clapeyron equation — links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
B.Clausius-Clapeyron equation — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
C.Clausius-Clapeyron equation — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
D.Clausius-Clapeyron equation — shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
20. Which term means: "temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases"?
A.Joule-Thomson coefficient — degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
B.Joule-Thomson coefficient — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
C.Joule-Thomson coefficient — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
D.Joule-Thomson coefficient — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
A.Van't Hoff equation — shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
B.Van't Hoff equation — difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation
C.Van't Hoff equation — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
D.Van't Hoff equation — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
A.temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
B.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
C.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
D.difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation
26. Which term means: "difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation"?
A.Excess Gibbs energy — difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation
B.Excess Gibbs energy — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
C.Excess Gibbs energy — correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
D.Excess Gibbs energy — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
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