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WorksheetsMass Transfer 1
Total questions: 15
Worksheet time: 8mins
Mass Transfer Coefficients are of great importance since
They control the time at which equilibrium is approached
Control size of equipment used
Control the cost of equipment used
All the above
The law which related the Flux J and concentration gradient is
Fick's I law
Fourier's Law of conduction
Newton's Law of Cooling
None of the above
Wilke Lee modification of Diffusivity prediction is applicable for
Mixtures of Non polar gases
mixture of polar with non polar gases
liquids
Option 1 and 2
Steady state diffusion of A through non diffusing B has the following value
Na= - Nb
Na = Nb
Na = constant, Nb =0
Nb= constant , Na=0
The Diffusivity of gases can be measured by special techniques like using radioactive tracers
True
False
SI unit of diffusivity is
m2/s
cm2/s
kmol/m2hr
kmol/m2s
What does Φ mean in Wilke Chang equation
association factor for solvent
diffusivity
solute molal volume
Temperature
Knudsen diffusion occurs for
for liquid samples
d/ λ >20
d/ λ <0.2
none of the above
Which is not a commonly used assumption in Interphase mass transfer
The only diffusional resistances are present in bulk fluids
the concentration at interphases are at equilibrium
The only diffusional resistances are present at the interphase
There is no resistance across interphase region
Choose the incorrect option:
For solute A very soluble in liquid
m' is small
rate is gas phase controlled
rate is liquid phase controlled
small concentration in gas will provide large concentration in gas
Unit of kg is
moles / (area)(time) (mole fraction)
moles / (area)(time) (pressure)
moles / (area)(time) (concentration)
moles / (area)(time)
F = (DAB)/(c*z)
True
False
Choose the correct option
Flux = Coefficient
Flux = Coefficient / concentration gradient
Flux = concentration gradient
Flux = Coefficient * concentration gradient
In actual it is observed that for turbulent flow k is proportional to DABn, where n =
1.5
0.8
∞
1
In surface renewal theory , "s" is
solubility
Solid boundary
fractional rate of replacement of elements
none of the above
