Test: Fick’s Law - Chemical Engineering MCQ

What is the molecular weight of Sulphur-dioxide?

 What is the molecular volume of air at normal boiling point? 

What is the value of Schmidt number for hydrogen?

Estimate the diffusion coefficient for ammonia in air t 25 degree Celsius temperature and one atmospheric pressure.
For ammonia,
Molecular weight = 17
Molecular volume = 25.81 cm³/gm mole
For air,
Molecular weight = 29 

Estimate the diffusion coefficient of carbon monoxide through air in which the mole fractions of each constituents are
O ₂ = 0.18
N ₂ = 0.72
CO = 0.10
The gas mixture is at 300 K and 2 atmosphere total pressure. The diffusivity values are
D _CO = 18.5 * 10 ^-6 m²/s at 273 K, 1 atm
D _CN = 19.2 * 10 ^-6 m²/s at 288 K, 1 atm
The subscripts C is carbon monoxide, O is oxygen and N is nitrogen 

What is the molecular weight of Sulphur-dioxide?

The dimension of diffusion coefficient is given by 

For what kind of mixtures D_AB=D_BA holds? 

 In the expression for molar flux N_A=(N_A+N_B)C_A/C – D_ABdC_A/dz, the terms representing bulk flow and molecular diffusion are, respectively 

Consider loss of ethanol vapor by diffusion from a half-filled open test tube. At what point in the diffusion path will the contribution of the bulk flow term to the molar flux be maximum?

A reaction 3A+2B+C=1.5D+E occurs in a reactor at steady state. What will be the value of the flux ratio N_A/N_D 

For a component A of a mixture, concentration as a function of x is given:
C_A=5e^-10x (x is in cm and C_A in mol/liter)
Calculate the value of diffusion velocity (m/s)of the component A at the point x=0, if diffusivity of A in the mixture is 2.567*10^-5m²/s. 

A sheet of Fe 1.0 mm thick is exposed to a oxidizing gas on one side and a deoxidizing gas on the other at 725°C. After reaching steady state, the Fe membrane is exposed to room temperature, and the C concentrations at each side of the membrane are 0.012 and 0.075 wt%. Calculate the diffusion coefficient (m²/sec) if the diffusion flux is 1.4×10^-8kg/m²-sec. 

At which condition molar flux with respect to a stationary observer and with respect to a observer moving with molar average velocity?

Which among the following is the statement of the ‘Fick’s Law’?

 In industries titanium is hardened through diffusion of carbon. The concentration of carbon at 1mm into the surface of the titanium slab is 0.25kg/m³ and at 3mm the concentration is 0.68kg/m³. The rate at which the carbon is entering into its surface is 1.27*10-9kg/m².s. calculate the value of diffusion coefficient of carbon. 

Fick’s law is given by the formula