4.1. Equation Derivations

Try these first

1. 1.

   What is the mass transfer coefficient?

   Hint

   Think about the units associated with mass transfer.

2. 2.

   What does Henry’s Law relate in mass transfer?

   Hint

   Remember the gas-liquid equilibrium relationship.

3. 3.

   What is the overall mass transfer flux related to?

   • The concentration difference
   • Temperature difference
   • Pressure difference

   Hint

   Think about what drives mass transfer.

4. 4.

   True or False: The mass transfer coefficient is the same for both liquid and gas phases.

   • True
   • False

   Hint

   Reflect on the definition of mass transfer coefficients.

5. 5.

   Given that a chemical has a concentration of 20 mg/L in water and 0.5 mg/L in the air, calculate the mass transfer flux if the liquid and gas coefficients are 5.0 m/s and 2.0 m/s respectively.

   Hint

   Use the flux formula to account for individual mass transfer resistances.

6. 6.

   A factory discharges wastewater with a concentration of a pollutant at 50 mg/L into a river with a concentration of 2 mg/L. If the mass transfer coefficients are 10 m/s for water and 5 m/s for air, determine how quickly the pollutant will spread to the air.

   Hint

   Remember to apply the resistance in the formula correctly.