Interphase mass transfer refers to mass transfer between:
A
Two phases in chemical equilibrium
C
Same phase at different locations
Analysis & Theory
Interphase mass transfer occurs between two different phases, such as gas-liquid or liquid-solid.
The resistance to interphase mass transfer is generally assumed to exist in:
C
Both phases near the interface
Analysis & Theory
Mass transfer resistance is typically present in the boundary layers of both phases near the interface.
Which model assumes that mass transfer occurs only in one phase?
Analysis & Theory
Film theory assumes a stagnant film in one phase through which diffusion occurs.
The two-film theory is commonly used to model interphase mass transfer. It assumes:
A
Turbulent flow at interface
B
Instantaneous equilibrium at the interface
C
No concentration gradient
D
Equal mass transfer coefficients in both phases
Analysis & Theory
The two-film theory assumes equilibrium exists at the interface, with resistances on both sides.
In gas-liquid systems, mass transfer rate is affected by:
C
Mass transfer coefficient
Analysis & Theory
Mass transfer rate depends on solubility, interfacial area, and transfer coefficient.
The overall mass transfer coefficient accounts for:
A
Resistance in the gas phase only
B
Resistance in the liquid phase only
C
Resistance in both phases
Analysis & Theory
The overall mass transfer coefficient includes resistances from both gas and liquid phases.
Which of the following increases interphase mass transfer?
B
Decreasing interfacial area
Analysis & Theory
Turbulence enhances mixing, reduces boundary layer thickness, and increases mass transfer.
The unit of mass transfer coefficient (k) in SI units is:
Analysis & Theory
Mass transfer coefficient has units of velocity: meters per second (m/s).
When a gas dissolves into a liquid during mass transfer, the process is controlled by:
A
Only gas side resistance
B
Only liquid side resistance
C
The phase with higher resistance
Analysis & Theory
The slower phase (higher resistance) controls the rate of interphase mass transfer.
Interfacial equilibrium in mass transfer means:
A
No concentration gradient
B
Equal partial pressures
C
Equal chemical potential or equilibrium distribution of solute
Analysis & Theory
At the interface, equilibrium means that solute concentrations satisfy the phase equilibrium relationship.