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. 0.5 Wi
- B. 1.34 Wi
- C. Wi
- D. 3.34 Wi
Explanation: Open-circuit grinding generally consumes more energy than closed-circuit grinding because particles are not repeatedly returned for…
Correct answer: 1.34 Wi- A. Titanium oxide
- B. Calcium oxide
- C. Cobalt oxide
- D. Manganese oxide
Explanation: Hematite is mainly Fe2O3 and may contain common gangue or impurity oxides such as TiO2, CaO, and MnO.
Correct answer: Cobalt oxide1883. In case of a ball mill ?
- A. None of these
- B. Fine feed requires a larger ball
- C. Operating speed should be more than the critical speed
- D. Coarse feed requires a larger ball
Explanation: Coarse feed particles need larger balls so that the impact force is sufficient to break them.
Correct answer: Coarse feed requires a larger ball1884. General mechanism of size reduction in intermediate and fine grinder is by __________________?
- A. Impact and attrition
- B. Compression
- C. Compression and tearing
- D. Cutting action
Explanation: Intermediate and fine grinders mainly reduce size through impact, which fractures particles, and attrition, which wears them down by…
Correct answer: Impact and attrition- A. tons/hr-ft2
- B. tons/ft2
- C. Both A. & B.
- D. tons/hr
Explanation: Screen capacity must indicate both the mass processed per unit time and the screening area available, so it is expressed as tons per hour…
Correct answer: tons/hr-ft2- A. Energy fed to the machine to the surface energy created by crushing
- B. Energy absorbed by the solid to that fed to the machine
- C. Surface energy created by crushing to the energy absorbed by the solid
- D. Energy absorbed by the solid to the surface energy created by crushing
Explanation: Crushing efficiency compares the useful surface energy produced in creating new surfaces with the energy absorbed by the solid.
Correct answer: Surface energy created by crushing to the energy absorbed by the solid- A. 1.5
- B. 1
- C. > 1
- D. < 1
Explanation: A conventional ball mill is relatively short and has a length-to-diameter ratio below unity.
Correct answer: < 1- A. Mulling
- B. Kneading
- C. Dispersion
- D. None of these
Explanation: A pan mixer uses mulling, in which heavy blades or rollers knead and compress material against the pan while turning it over.
Correct answer: Mulling- A. 0.01 L.S
- B. 0.087 L.S
- C. L.S
- D. L.S/0.087
Explanation: For the stated centimetre dimensions, the empirical jaw or gyratory crusher capacity relation is Q = 0.087LS tons per hour.
Correct answer: 0.087 L.S- A. Both A. & B.
- B. Disk-bowl
- C. Ultra
- D. Neither A. nor B.
Explanation: Isotope separation requires extremely high centrifugal fields because isotopes differ only slightly in mass.
Correct answer: Ultra- A. 1-5
- B. 40-50
- C. 75-80
- D. 90-95
Explanation: Only a small fraction of the energy supplied to a ball mill produces new particle surface; most is lost through friction, heat, and…
Correct answer: 1-51892. In screen analysis, the notation +5 mm/-10 mm means particles passing through ____________________?
- A. 5 mm screen and retained on 10 mm screen
- B. 10 mm screen and retained on 5 mm screen
- C. Both 5 mm and 10 mm screens
- D. Neither 5 mm nor 10 mm screen
Explanation: The plus sign indicates material retained on the stated larger-size boundary, while the minus sign indicates material passing the stated…
Correct answer: 10 mm screen and retained on 5 mm screen- A. N ∝ D
- B. N ∝ √D
- C. N ∝ 1/√D
- D. N ∝ 1/D
Explanation: At critical speed, the balance between centrifugal and gravitational effects gives N proportional to the inverse square root of diameter.
Correct answer: N ∝ 1/√D- A. Secondary
- B. Fine
- C. Ultrafine
- D. Primary
Explanation: Primary crushing reduces very large feed, commonly about 300 to 1500 mm, to products roughly 100 to 300 mm.
Correct answer: Primary- A. Sand
- B. Vacuum
- C. Plate & frame
- D. Rotary
Explanation: A sand filter can handle very large water volumes and retain small quantities of suspended precipitate at relatively low operating cost.
Correct answer: Sand- A. Taggarts rule
- B. Fick's law
- C. Rittinger's Law
- D. None of these
Explanation: Rittinger's law states that the energy required for size reduction is proportional to the new surface area created.
Correct answer: Rittinger's Law- A. 0.01 to 0.1
- B. 4 to 5
- C. 2 to 3.5
- D. 0.5 to 1.5
Explanation: The power requirement for crushing is commonly of the order of 0.5 to 1.5 kWh per ton of material.
Correct answer: 0.5 to 1.5- A. 1000°C and 10 atm
- B. 200°C and 5 atm
- C. 500°C and 50 atm
- D. 1000°C and 500 atm
Explanation: Electrostatic precipitators can treat dust-laden gases at temperatures approaching 1000°C and pressures around 10 atm in the stated…
Correct answer: 1000°C and 10 atm1899. The specific surface of spherical particles is proportional to (where, Dp = diameter of particle)?
- A. D2
- B. 1/Dp
- C. Dp
- D. 1/D2p
Explanation: For a sphere, surface area divided by volume is πD²/(πD³/6), which simplifies to 6/D.
Correct answer: 1/Dp- A. Propeller
- B. Flat blade turbine
- C. Helical screw
- D. Curved blade turbine
Explanation: A helical-screw agitator has a large blade area and produces strong axial movement at low speed, making it suitable for very viscous…
Correct answer: Helical screw