Mass Transfer interview questions

1. A.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
2. B.diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
3. C.graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow
4. D.liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages

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1. A.Azeotrope
2. B.Constant-rate vs falling-rate drying
3. C.Fick's law
4. D.Wet-bulb temperature

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1. A.Fick's law — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
2. B.Fick's law — diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
3. C.Fick's law — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
4. D.Fick's law — surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls

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1. A.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
2. B.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
3. C.ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
4. D.ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1

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1. A.Extraction solvent selectivity
2. B.Relative volatility
3. C.Fick's law
4. D.McCabe-Thiele method

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1. A.Relative volatility — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
2. B.Relative volatility — ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
3. C.Relative volatility — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
4. D.Relative volatility — liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages

Answer + AI explanation with Pro

1. A.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
2. B.ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
3. C.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
4. D.liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages

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1. A.Relative volatility
2. B.McCabe-Thiele method
3. C.Two-film theory
4. D.Reflux ratio

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1. A.Reflux ratio — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
2. B.Reflux ratio — liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages
3. C.Reflux ratio — constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
4. D.Reflux ratio — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1

Answer + AI explanation with Pro

1. A.graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow
2. B.liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages
3. C.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
4. D.steady temperature reached by a wetted thermometer in flowing unsaturated air, nearly equal to the adiabatic saturation temperature for air-water

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1. A.Wet-bulb temperature
2. B.Fick's law
3. C.Azeotrope
4. D.Extraction solvent selectivity

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1. A.Wet-bulb temperature — steady temperature reached by a wetted thermometer in flowing unsaturated air, nearly equal to the adiabatic saturation temperature for air-water
2. B.Wet-bulb temperature — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
3. C.Wet-bulb temperature — diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
4. D.Wet-bulb temperature — surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls

Answer + AI explanation with Pro

1. A.graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow
2. B.ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
3. C.ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
4. D.diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant

Answer + AI explanation with Pro

1. A.McCabe-Thiele method
2. B.Two-film theory
3. C.Wet-bulb temperature
4. D.Fick's law

Answer + AI explanation with Pro

1. A.McCabe-Thiele method — diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
2. B.McCabe-Thiele method — liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages
3. C.McCabe-Thiele method — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
4. D.McCabe-Thiele method — graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow

Answer + AI explanation with Pro

1. A.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
2. B.surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls
3. C.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%
4. D.ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1

Answer + AI explanation with Pro

1. A.Relative volatility
2. B.Extraction solvent selectivity
3. C.Wet-bulb temperature
4. D.Azeotrope

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1. A.Azeotrope — liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages
2. B.Azeotrope — surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls
3. C.Azeotrope — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
4. D.Azeotrope — constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%

Answer + AI explanation with Pro

1. A.diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
2. B.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
3. C.surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls
4. D.graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow

Answer + AI explanation with Pro

1. A.Two-film theory
2. B.Reflux ratio
3. C.McCabe-Thiele method
4. D.Wet-bulb temperature

Answer + AI explanation with Pro

1. A.Two-film theory — graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow
2. B.Two-film theory — absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
3. C.Two-film theory — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
4. D.Two-film theory — liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages

Answer + AI explanation with Pro

1. A.surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls
2. B.graphical stage count for binary distillation stepping between the equilibrium curve and operating lines, assuming constant molal overflow
3. C.diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant
4. D.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium

Answer + AI explanation with Pro

1. A.Fick's law
2. B.Constant-rate vs falling-rate drying
3. C.Relative volatility
4. D.Reflux ratio

Answer + AI explanation with Pro

1. A.Constant-rate vs falling-rate drying — steady temperature reached by a wetted thermometer in flowing unsaturated air, nearly equal to the adiabatic saturation temperature for air-water
2. B.Constant-rate vs falling-rate drying — ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
3. C.Constant-rate vs falling-rate drying — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
4. D.Constant-rate vs falling-rate drying — surface stays saturated and air conditions set the rate until the critical moisture content; below it internal diffusion controls and the rate falls

Answer + AI explanation with Pro

1. A.absorption model placing all resistance in stagnant gas and liquid films on either side of an interface that is itself at equilibrium
2. B.liquid returned to the column top divided by distillate withdrawn; the minimum value needs infinite stages and total reflux gives the minimum stages
3. C.ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
4. D.constant-boiling mixture whose vapour composition equals its liquid composition so simple distillation cannot cross it, as for ethanol-water at 95.6 wt%

Answer + AI explanation with Pro

1. A.McCabe-Thiele method
2. B.Relative volatility
3. C.Reflux ratio
4. D.Extraction solvent selectivity

Answer + AI explanation with Pro

1. A.Extraction solvent selectivity — ratio of the vapour-liquid K-values of two components; separation by ordinary distillation is impossible when it equals 1
2. B.Extraction solvent selectivity — ratio of distribution coefficients of solute and carrier in the solvent; a solvent is chosen for high selectivity, density difference and easy recovery
3. C.Extraction solvent selectivity — steady temperature reached by a wetted thermometer in flowing unsaturated air, nearly equal to the adiabatic saturation temperature for air-water
4. D.Extraction solvent selectivity — diffusive molar flux is proportional to the negative concentration gradient, with molecular diffusivity as the proportionality constant

Answer + AI explanation with Pro