Separation Processes Questions and Answers – Steady and Unsteady State Mass Transfer Through Stationary Media

«
»

This set of Separation Processes Questions and Answers for Experienced people focuses on “Steady and Unsteady State Mass Transfer Through Stationary Media”.

1. The molar diffusion flux for a cylinder with inner radius r1 and outer radius r2 is directly proportional to:
a) Ln(r2/r1)
b) R2/r1
c) 1/ln(r1/r2)
d) 1/ln(r2/r1)
View Answer

Answer: d
Explanation: The molar diffusion flux for a cylinder with inner radius r1 and outer radius r2 is 2LDab(ca1-ca2)/ ln(r2/r1).
advertisement

2. The molar diffusion flux for a plane wall with thickness z2-z1 is directly proportional to:
a) Z2
b) Z2-z1
c) 1/z2-z1
d) Z1-z2
View Answer

Answer: c
Explanation: The molar diffusion flux for a plane wall with thickness z2-z1 is Dab(ca1-ca2)/ z2-z1.

3. The molar diffusion flux for a spherical shell with inner radius r1 and outer radius r2 is directly proportional to
a) 4r1r2/r2-r1
b) r2-r1/4r1r2
c) r1r2/r2-r1
d) 2r1r2/r2-r1
View Answer

Answer: a
Explanation: The molar diffusion flux for a spherical shell with inner radius r1 and outer radius r2 is 4r1r2 Dab(ca1-ca2)/r2-r1.

4. For which mass transfer the area log mean is considered?
a) Through a sphere
b) Through a cylinder
c) Through a wall
d) Through a ball
View Answer

Answer: b
Explanation: The mass transfer through a cylinder is given by the formula 2Lab(ca1-ca2)/ ln(r2/r1).Hence log mean of the area is considered.

5. For which mass transfer the area geometric mean is considered?
a) Through a sphere
b) Through a cylinder
c) Through a wall
d) Through a pipe
View Answer

Answer: a
Explanation: The molar diffusion flux for a spherical shell with inner radius r1 and outer radius r2 is 4r1r2 Dab(ca1-ca2)/r2-r1.Hence the geometric mean area is considered.
advertisement

6. The molar diffusion rate of A in stationary B in only z direction is given by:
a) DabA(ΔCa/Δz)
b) DabA(Δz)
c) -DabA(ΔCa/Δz)
d) DabA(ΔCa)
View Answer

Answer: c
Explanation: The molar diffusion rate of A in stationary B in only z direction is given by -DabA(ΔCa/Δz).

7. For one dimensional diffusion in the radial direction only for cylinder and sphere, the fick’s second law becomes:
a) ΔCa/ΔT= Dab/r(Δ/Δr(rΔCa/Δr)
b) ΔCa/ΔT= Dab/(Δ/Δr(ΔCa/Δr)
c) -ΔCa/ΔT= Dab/r(Δ/Δr(rΔCa/Δr)
d) ΔCa/ΔT= Dab/r(Δ/Δr(r/Δr)
View Answer

Answer: a
Explanation: For one dimensional diffusion in the radial direction only for cylinder and sphere, the fick’s law becomes ΔCa/ΔT= Dab/r(Δ/Δr(rΔCa/Δr).

8. The fick’s second law is analogous to:
a) Newton;s second law
b) Newton’s third law
c) Fourier’s second law
d) Fourier’s first law
View Answer

Answer: c
Explanation: The fick’s second law is analogous to fourier’s second law where ca is replaced by temperature T and and Dab by thermal diffusivity.

9. Which equation is concerned with adsorption equilibria.
a) Gibb’s equation
b) Fourier’s law
c) Fick’s law
d) Freundlich’s equation
View Answer

Answer: d
Explanation: the freunlich’s equation of x/m = Kp1/n is concerned with adsorption equilibria.
advertisement

10. For a wetted watch tower, what is the area of mass transfer?
a) Rectangular
b) Spherical
c) Cylindrical
d) Hexagonal
View Answer

Answer: c
Explanation: The shape of a watch tower is cylindrical, hence the area must be cylindrical.

Sanfoundry Global Education & Learning Series – Separation Processes.

To practice all areas of Separation Processes for Experienced people, here is complete set of 1000+ Multiple Choice Questions and Answers.

Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

advertisement
advertisement
advertisement
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn