Chemical Engineering Thermodynamics interview questions

1. A.degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
2. B.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
3. C.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
4. D.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume

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1. A.Steady-flow energy equation
2. B.Activity coefficient
3. C.Raoult's law
4. D.Van't Hoff equation

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1. 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
2. B.Steady-flow energy equation — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
3. 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
4. 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

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1. A.degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
2. B.temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
3. C.correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
4. D.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume

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1. A.Van't Hoff equation
2. B.Excess Gibbs energy
3. C.Raoult's law
4. D.Gibbs phase rule

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1. A.Gibbs phase rule — degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
2. 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
3. C.Gibbs phase rule — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
4. 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

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1. A.degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
2. B.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
3. C.effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
4. D.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume

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1. A.Raoult's law
2. B.Fugacity
3. C.Activity coefficient
4. D.Clausius-Clapeyron equation

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1. A.Fugacity — links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
2. B.Fugacity — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
3. C.Fugacity — effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
4. D.Fugacity — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction

Answer + AI explanation with Pro

1. A.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
2. B.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
3. C.effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
4. D.partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction

Answer + AI explanation with Pro

1. A.Raoult's law
2. B.Clausius-Clapeyron equation
3. C.Joule-Thomson coefficient
4. D.Van't Hoff equation

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1. A.Raoult's law — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
2. B.Raoult's law — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
3. C.Raoult's law — effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
4. D.Raoult's law — shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²

Answer + AI explanation with Pro

1. A.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
2. B.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
3. C.correction factor multiplying mole fraction in modified Raoult's law for non-ideal liquids, obtained from models such as Wilson, NRTL or UNIQUAC
4. D.effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas

Answer + AI explanation with Pro

1. A.Activity coefficient
2. B.Steady-flow energy equation
3. C.Fugacity
4. D.Van't Hoff equation

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1. A.Activity coefficient — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
2. B.Activity coefficient — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
3. 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
4. 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

Answer + AI explanation with Pro

1. A.effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
2. B.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
3. C.first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
4. D.partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction

Answer + AI explanation with Pro

1. A.Gibbs phase rule
2. B.Clausius-Clapeyron equation
3. C.Excess Gibbs energy
4. D.Fugacity

Answer + AI explanation with Pro

1. 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
2. B.Clausius-Clapeyron equation — first-law balance for open systems where changes in enthalpy, kinetic and potential energy equal heat added minus shaft work
3. 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
4. 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

Answer + AI explanation with Pro

1. A.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
2. B.temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
3. C.effective pressure replacing partial pressure in equilibrium relations for real gases, equal to the pressure itself for an ideal gas
4. D.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²

Answer + AI explanation with Pro

1. A.Excess Gibbs energy
2. B.Gibbs phase rule
3. C.Activity coefficient
4. D.Joule-Thomson coefficient

Answer + AI explanation with Pro

1. A.Joule-Thomson coefficient — degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
2. B.Joule-Thomson coefficient — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
3. C.Joule-Thomson coefficient — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
4. 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

Answer + AI explanation with Pro

1. A.partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
2. B.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
3. C.degrees of freedom F = C − P + 2, so a pure substance with two phases present has only one independent variable
4. D.temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases

Answer + AI explanation with Pro

1. A.Steady-flow energy equation
2. B.Van't Hoff equation
3. C.Joule-Thomson coefficient
4. D.Raoult's law

Answer + AI explanation with Pro

1. 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
2. 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
3. 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
4. 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

Answer + AI explanation with Pro

1. A.temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases
2. B.links vapour-pressure slope with temperature to latent heat, d ln P/dT = ΔH/RT², assuming ideal vapour and negligible liquid volume
3. C.shows ln K rising with temperature for endothermic reactions and falling for exothermic ones, since d ln K/dT = ΔH°/RT²
4. D.difference between real and ideal-solution Gibbs energy of mixing, from which activity coefficients are derived consistently with the Gibbs-Duhem relation

Answer + AI explanation with Pro

1. A.Fugacity
2. B.Excess Gibbs energy
3. C.Joule-Thomson coefficient
4. D.Gibbs phase rule

Answer + AI explanation with Pro

1. 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
2. B.Excess Gibbs energy — partial pressure of a component above an ideal solution equals its pure vapour pressure times its liquid mole fraction
3. 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
4. D.Excess Gibbs energy — temperature change per unit pressure drop at constant enthalpy; positive below the inversion temperature so throttling cools most gases

Answer + AI explanation with Pro