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Chemical Engineering :: Mass Transfer

  1. Surface renewal model of mass transfer was enunciated by

  2. A.
    Toor and Marchello
    B.
    Fick
    C.
    Danckwerts
    D.
    Stefan

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  3. When the __________ the relative humidity of air decreases, despite an increase in the absolute humidity.

  4. A.
    temperature rises
    B.
    pressure rises
    C.
    temperature falls
    D.
    pressure falls

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  5. For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as

  6. A.
    Re0.33
    B.
    Re0.53
    C.
    Re0.83
    D.
    Re

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  7. The relative humidity of air decreases in-spite of an increase in the absolute humidity, when the

  8. A.
    temperature rises.
    B.
    pressure rises.
    C.
    temperature falls.
    D.
    pressure falls.

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  9. Unit of molal diffusivity is

  10. A.
    cm2/sec gm . mole
    B.
    gm moles/cm2 . sec
    C.
    gm moles/cm. sec
    D.
    gm moles/cm2. sec

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  11. The term "approach" in a cooling tower refers to the difference in the temperature of the

  12. A.
    cold water leaving the tower and the wet bulb temperature of the surrounding air.
    B.
    hot water entering the tower and the wet bulb temperature of the surrounding air.
    C.
    hot water entering and the cooled water leaving the cooling tower.
    D.
    none of these

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  13. Binary distillation involves the mass transfer by __________ at the gas-liquid interface.

  14. A.
    unidirectional diffusion from liquid to gas phase
    B.
    unidirectional diffusion from gas to liquid phase
    C.
    either 'a' or 'b'
    D.
    a counter diffusion at an almost equal molar rate

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