2.2. Definition of Mass Transfer Coefficients

Try these first

1. 1.

   What does the mass transfer coefficient represent?

   Hint

   Think of it as a speed measurement for molecules moving between phases.

2. 2.

   What are the two phases typically involved in mass transfer problems?

   Hint

   Consider common examples of phase interactions.

3. 3.

   What is a mass transfer coefficient?

   • A measure of temperature change
   • A measure of solute transfer rate
   • A measure of pressure difference

   Hint

   It's related to how substances diffuse.

4. 4.

   Henry's Law relates gas solubility to what?

   • True
   • False

   Hint

   Think about how gases interact with their liquids.

5. 5.

   Consider a lake where the concentration of a pollutant is measured to be 15 mg/L. The ambient air has a concentration of 0.2 mg/L. If the mass transfer coefficient for water is estimated to be 2.5 m/s and for air is 0.5 m/s, calculate the flux of the pollutant across the air-water interface.

   Hint

   Identify the interface concentrations using the known bulk values.

6. 6.

   In a chemical reactor, gas and liquid phases are reacting. You find the individual mass transfer coefficients as 1.2 m/s and 0.8 m/s respectively. The total equivalent resistance is 100. What is the implication for the rate of mass transfer and what changes would improve efficiency?

   Hint

   Determine which phase needs adjustments to optimize mass transfer rates.