Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Sphere
- B. Cube
- C. Cylinder (L/D = 1)
- D. Raschig rings
Explanation: Sphericity is at most unity, and only a sphere has the minimum surface area for a given volume.
Correct answer: Sphere- A. Assumption that all particles in a single fraction are equal in size
- B. Assumption that all particles in a single fraction are equal in size, is not needed
- C. Fact that screening is more effective
- D. None of these
Explanation: Cumulative analysis avoids assuming that every particle in a size fraction has one representative size, an assumption required in…
Correct answer: Assumption that all particles in a single fraction are equal in size, is not needed- A. Weight
- B. Volume
- C. Either A. or B.
- D. Neither A. nor B.
Explanation: Specific surface area may be expressed per unit mass or per unit volume, depending on whether a mass-based or volume-based definition is…
Correct answer: Either A. or B.- A. Blake jaw crusher
- B. Bradford's breaker
- C. Stamp mill
- D. Cage mill
Explanation: A cage mill uses rapidly rotating impact and attrition elements and is suitable for reducing fibrous materials such as wood, asbestos and…
Correct answer: Cage mill- A. None of these
- B. Hydrocyclones
- C. Dorr Oliver rake classifier
- D. Sharpies super-centrifuge
Explanation: Sharpies super-centrifuges, hydrocyclones and Dorr Oliver rake classifiers all classify particles in a liquid medium.
Correct answer: None of these- A. Compression
- B. Interparticle attrition
- C. Cutting
- D. Impact
Explanation: Fluid energy mills suspend particles in high-velocity gas jets, causing particles to collide with one another.
Correct answer: Interparticle attrition1827. Ultracentrifuges running at speeds upto 100000 rpm is normally used for the_____________________?
- A. Dewaxing of lubricating oil
- B. Concentration of rubber latex
- C. Separation of cream from milk
- D. Separation of isotopes based on their density or molecular weights difference
Explanation: Ultracentrifuges operating near 100,000 rpm generate extremely high centrifugal fields, allowing separation of isotopes or molecules with…
Correct answer: Separation of isotopes based on their density or molecular weights difference- A. All A, B. & C.
- B. Pre-coated on the filter medium prior to filtration
- C. Separated from the cake by dissolving solids or by burning it off
- D. Added to the feed slurry
Explanation: Filter aids may be mixed with the slurry or precoated on the filter medium to form a more porous cake with lower resistance.
Correct answer: All A, B. & C.- A. 1 - 2
- B. 15 - 20
- C. 40 - 50
- D. 60 - 75
Explanation: Trommels rotate slowly so that particles are lifted and then cascade through the cylindrical screen; their usual speed is about 15 to 20…
Correct answer: 15 - 20- A. 6/D.ρ
- B. 2/D.ρ
- C. 4/D.ρ
- D. 12/D.ρ
Explanation: For a sphere, surface area divided by volume is πD² divided by πD³/6, giving 6/D; dividing by density gives the mass-based specific…
Correct answer: 6/D.ρ- A. Vibrating screen
- B. Grizzly
- C. Shaking screen
- D. Trommel
Explanation: Vibrating screens provide high-frequency motion and are effective for sizing fine particles.
Correct answer: Vibrating screen- A. Size of the grinding media
- B. Length to diameter ratio
- C. Final product size
- D. Operating speed
Explanation: A tube mill is relatively long and narrow, giving it a higher length-to-diameter ratio than a ball mill.
Correct answer: Length to diameter ratio- A. Concentrate
- B. Tailing
- C. Middling
- D. None of these
Explanation: Coal washing produces clean coal, refuse, and middlings. Middlings are the intermediate product containing concentrated mineral matter and…
Correct answer: Middling- A. Filters
- B. Thickness
- C. Cyclones
- D. Sorting classifier
Explanation: A sorting classifier separates solid particles according to differences in properties such as density, size, or shape.
Correct answer: Sorting classifier- A. Skip hoist
- B. Bucket elevator
- C. Screw conveyor
- D. None of these
Explanation: A skip hoist lifts and discharges batches of raw materials into the top of a blast furnace.
Correct answer: Skip hoist- A. Collector
- B. Frother
- C. Modifier
- D. Activator
Explanation: Pine oil lowers the surface tension of the pulp and helps produce a stable froth, so it acts as a frother.
Correct answer: Frother- A. Wheat
- B. Wet clay
- C. Sand
- D. None of these
Explanation: Wet clay is cohesive because water and clay particles develop attractive forces that make the mass stick together.
Correct answer: Wet clay- A. Bond's crushing law
- B. Kick's law
- C. None of these
- D. Rittinger's law
Explanation: Rittinger’s law is most suitable for fine grinding because the energy required is related to the new surface area produced.
Correct answer: Rittinger's law- A. Dry
- B. Wet
- C. Ultrafine
- D. Intermediate
Explanation: Grinding aids are commonly added during dry grinding to reduce particle agglomeration and coating of the grinding surfaces.
Correct answer: Dry- A. Separation efficiency
- B. Selectivity index
- C. Concentration ratio
- D. None of these
Explanation: The selectivity index combines separation performance into one measure by taking the geometric mean of the relative recoveries and…
Correct answer: Selectivity index