PIChE Practice Exam

Question 1

What is the main factor that affects the velocity of a fluid in a pipe?
Pipe diameter
Fluid density
Fluid viscosity
Pressure difference

Answer 1

Pressure difference

Question 2

What is the purpose of using a packed bed in a chemical process?
To provide a large surface area for heat transfer
To provide a large surface area for mass transfer
To provide a small surface area for mass transfer
To provide a small surface area for heat transfer

Answer 2

To provide a large surface area for mass transfer

Question 3

What is the main difference between natural convection and forced convection in heat transfer?
Natural convection is driven by gravity, while forced convection is driven by a pump.
Natural convection is driven by a pump, while forced convection is driven by gravity.
Natural convection is characterized by a chaotic flow pattern, while forced convection is characterized by a smooth flow pattern.
Natural convection is characterized by a smooth flow pattern, while forced convection is characterized by a chaotic flow pattern.

Answer 3

Natural convection is driven by gravity, while forced convection is driven by a pump.

Question 4

What is the main difference between diffusive mass transfer and convective mass transfer?
Diffusive mass transfer is driven by a concentration gradient, while convective mass transfer is driven by a velocity gradient.
Diffusive mass transfer is driven by a velocity gradient, while convective mass transfer is driven by a concentration gradient.
Diffusive mass transfer is characterized by a chaotic flow pattern, while convective mass transfer is characterized by a smooth flow pattern.
Diffusive mass transfer is characterized by a smooth flow pattern, while convective mass transfer is characterized by a chaotic flow pattern.

Answer 4

Diffusive mass transfer is driven by a concentration gradient, while convective mass transfer is driven by a velocity gradient.

Question 5

What is the purpose of using a heat exchanger in a chemical process?
To cool a hot fluid
To heat a cold fluid
To cool and heat fluids simultaneously
To transfer heat from one fluid to another

Answer 5

To transfer heat from one fluid to another

Question 6

What is the process used to purify and separate a mixture of gases into its individual components?
Distillation
Fractional Distillation
Extraction
Adsorption

Answer 6

Fractional Distillation

Question 7

What is the process used to separate a mixture of liquids based on their boiling points?
Distillation
Fractional Distillation
Extraction
Adsorption

Answer 7

Distillation

Question 8

What is the purpose of the gas-liquid separator in a chemical process?
To separate solid and liquid phases
To separate vapor and liquid phases
To separate liquid and liquid phases
To separate vapor and solid phases

Answer 8

To separate vapor and liquid phases

Question 9

What is the main difference between laminar and turbulent flow in transport phenomena?
Laminar flow has a lower Reynolds number, while turbulent flow has a higher Reynolds number.
Laminar flow has a higher Reynolds number, while turbulent flow has a lower Reynolds number.
Laminar flow is characterized by a smooth flow pattern, while turbulent flow is characterized by a chaotic flow pattern.
Laminar flow is characterized by a chaotic flow pattern, while turbulent flow is characterized by a smooth flow pattern.

Answer 9

Laminar flow is characterized by a smooth flow pattern, while turbulent flow is characterized by a chaotic flow pattern.

Explanation:
Laminar flow is a type of fluid flow that occurs when a fluid flows in parallel layers, with no turbulence or mixing between layers. This results in a smooth, orderly flow pattern. In contrast, turbulent flow occurs when a fluid is subjected to a large amount of turbulence and mixing, causing a chaotic and disordered flow pattern. This type of flow is characterized by eddies and vortices, which cause the fluid to mix and transfer energy in a highly inefficient manner.

Question 10

What is the main difference between laminar and turbulent flow in transport phenomena?
Laminar flow has a lower Reynolds number, while turbulent flow has a higher Reynolds number.
Laminar flow has a higher Reynolds number, while turbulent flow has a lower Reynolds number.
Laminar flow is characterized by a smooth flow pattern, while turbulent flow is characterized by a chaotic flow pattern.
Laminar flow is characterized by a chaotic flow pattern, while turbulent flow is characterized by a smooth flow pattern.

Answer 10

Laminar flow is characterized by a smooth flow pattern, while turbulent flow is characterized by a chaotic flow pattern.

Explanation:
Laminar flow is a type of fluid flow that occurs when a fluid flows in parallel layers, with no turbulence or mixing between layers. This results in a smooth, orderly flow pattern. In contrast, turbulent flow occurs when a fluid is subjected to a large amount of turbulence and mixing, causing a chaotic and disordered flow pattern. This type of flow is characterized by eddies and vortices, which cause the fluid to mix and transfer energy in a highly inefficient manner.

Question 11

What is the main driving force behind the flow velocity of a fluid in a pipe?
Pipe diameter
Fluid density
Fluid viscosity
Pressure gradient

Answer 11

Pressure gradient

Explanation:
The main factor that affects the velocity of a fluid in a pipe is the pressure difference, or pressure gradient, between the ends of the pipe. This difference in pressure drives the fluid to flow from the high-pressure region to the low pressure region, causing the fluid to move at a certain velocity. The diameter of the pipe, the density of the fluid, and the viscosity of the fluid can also affect the flow velocity, but the pressure gradient is the main driving force behind the flow.

Question 12

What is the purpose of using a packed bed in a chemical process?
To provide a large surface area for heat transfer
To provide a large surface area for mass transfer
To provide a small surface area for mass transfer
To provide a small surface area for heat transfer

Answer 12

To provide a large surface area for mass transfer

Explanation:
A packed bed is a type of column used in chemical processes to increase the surface area available for mass transfer. The packed bed is filled with small, solid particles (packing material) that provide a large surface area for chemical reactions and mass transfer to occur. The packed bed helps to increase the rate of mass transfer by providing a large surface area for the exchange of materials between the fluid and the packing material.

Question 13

What is the main difference between natural convection and forced convection in heat transfer?
Natural is driven by gravity, forced is driven by a pump.
Natural is driven by a pump, forced is driven by gravity.
Natural is chaotic, forced is smooth.
Natural is smooth, forced is chaotic.

Answer 13

Natural is driven by gravity, forced is driven by a pump.

Explanation:
Natural convection is a type of heat transfer where the fluid is driven by natural forces, such as gravity, and rises or falls as it heats up or cools down. In contrast, forced convection is a type of heat transfer where the fluid is driven by an external force, such as a pump, and circulates through the system.

Question 14

What is the main difference between diffusive mass transfer and convective mass transfer?
Diffusive mass transfer is driven by a concentration gradient, while convective mass transfer is driven by a velocity gradient.
Diffusive mass transfer is driven by a velocity gradient, while convective mass transfer is driven by a concentration gradient.
Diffusive mass transfer is characterized by a chaotic flow pattern, while convective mass transfer is characterized by a smooth flow pattern.
Diffusive mass transfer is characterized by a smooth flow pattern, while convective mass transfer is characterized by a chaotic flow pattern.

Answer 14

Diffusive mass transfer is driven by a concentration gradient, while convective mass transfer is driven by a velocity gradient.

Explanation:
Diffusive mass transfer occurs when a solute moves from a high concentration region to a low concentration region due to molecular diffusion. This transfer is driven by the concentration gradient, or the difference in concentration between the two regions. Convective mass transfer, on the other hand, occurs when a solute is transported by the movement of a fluid. This transfer is driven by the velocity gradient, or the difference in velocity between the two regions.

Question 15

What is the purpose of using a heat exchanger in a chemical process?
To cool a hot fluid
To heat a cold fluid
To cool and heat fluids simultaneously
To transfer heat from one fluid to another

Answer 15

To transfer heat from one fluid to another

Explanation:
A heat exchanger is a device that is used in a chemical process to transfer heat from one fluid to another. This is done without the two fluids mixing. The purpose of using a heat exchanger is to control the temperature of a chemical reaction or to heat or cool a fluid in a process.

Question 16

What is the main difference between wet granulation and dry granulation process in particle technology?
Wet granulation uses a liquid binder while dry granulation uses mechanical pressure
Wet granulation uses mechanical pressure while dry granulation uses a liquid binder
Wet granulation forms larger particles while dry granulation forms smaller particles
Wet granulation forms smaller particles while dry granulation forms larger particles

Answer 16

Wet granulation uses a liquid binder while dry granulation uses mechanical pressure

Explanation:
Wet granulation involves adding a liquid binder to a powder mixture to form a granulate, while dry granulation involves compressing the powder mixture into larger particles using mechanical pressure.

Question 17

Which particle size reduction method is best suited for the production of fine powders with a narrow size distribution?
Impact milling
Jet milling
Ball milling
Hammer milling

Answer 17

Jet milling

Explanation:
Jet milling uses high-velocity air or steam to collide particles against each other, leading to size reduction. This method is especially effective for producing fine powders with a narrow size distribution, as the particles are constantly being ground and re-ground until they reach the desired size.

Question 18

Which of the following is not a commonly used particle characterization method in particle technology?
Laser diffraction
Scanning electron microscopy
Dynamic light scattering
Surface tension measurement

Answer 18

Surface tension measurement

Explanation:
Surface tension measurement is not a commonly used method in particle technology for characterizing particle size, shape, and distribution. Laser diffraction, scanning electron microscopy, and dynamic light scattering are all commonly used methods for particle characterization.

Question 19

What is the formula for calculating the kinetic energy of an object?
KE = mv^2
KE = mgh
KE = mc^2
KE = 0.5mv^2

Answer 19

KE = 0.5mv^2

Question 20

What type of mass transfer occurs as a result of random molecular motion?
Convection
Diffusion
Advection
Solute transport

Answer 20

Diffusion

Explanation:
Diffusion is the transfer of mass due to random molecular motion. It occurs as a result of a difference in concentration and can be thought of as the spreading out of a solute in a solvent over time

Question 21

What is the main objective of process design in a chemical plant?
To optimize production efficiency
To minimize the environmental impact
To ensure safety of workers
To minimize production costs

Answer 21

To minimize production costs

Explanation:
The main objective of process design in a chemical plant is to minimize production costs while ensuring that the process is technically and economically feasible. This includes optimizing the use of raw materials, energy, and other resources, as well as designing the plant to minimize waste and emissions. Other factors, such as worker safety and environmental impact, are also important considerations, but minimizing production costs is the primary objective.

Question 22

A chemical engineer is designing a process to produce a chemical product. The process involves a reaction between two reactants at a high temperature and pressure. The engineer needs to determine the best reactor design for the process. Which type of reactor would be the most suitable for this process?
Batch reactor
Continuous flow reactor
Plug flow reactor
Mixed flow reactor

Answer 22

Plug flow reactor

Explanation:
A plug flow reactor (PFR) is a type of continuous flow reactor that provides ideal mixing and reaction conditions for a chemical reaction. In a PFR, the reactants flow through the reactor in a plug-like manner, with no radial mixing, providing ideal conditions for a reaction that requires high temperature and pressure. The PFR design ensures that the reactants remain in contact for the optimal amount of time, increasing the yield of the desired product.

Question 23

A chemical engineer is designing a distillation column to separate a mixture of two liquids with different boiling points. What type of distillation column should the engineer use to maximize the separation of the two liquids?
Simple distillation column
Rectifying distillation column
Stripping distillation column
Azeotropic distillation column

Answer 23

Rectifying distillation column

Explanation:
A rectifying distillation column is used to separate a mixture of two liquids with different boiling points by making use of the differences in their vapor pressures. The rectifying distillation column is designed to condense the vapor from the column, allowing the more volatile liquid to be collected as a distillate, and the less volatile liquid to be collected as a residue. The rectifying column provides the highest degree of separation between the two liquids, making it the most suitable choice for this process.

Question 24

A chemical engineer is designing a process to remove impurities from a liquid stream. Which unit operation would be the most appropriate for this process?
Evaporation
Filtration
Absorption
Extraction

Answer 24

Absorption

Explanation:
Absorption is a unit operation used to remove impurities from a gas or liquid stream by contacting it with a solid or liquid absorbent. The absorbent removes the impurities from the stream, producing a purified product. In this case, the engineer is looking to remove impurities from a liquid stream, making absorption the most appropriate choice for this process. The choice of absorbent and the specific design of the absorption process will depend on the nature of the impurities and the desired degree of purification.