4.2. Re-evaluation of Mass Balance

Try these first

1. 1.

   Define mass balance in environmental science.

   Hint

   Think about what it measures in terms of substances.

2. 2.

   What is partitioning constant?

   Hint

   Consider how chemicals behave in different environments.

3. 3.

   What is mass balance?

   • A measure of environmental contaminants
   • The total waste produced in a system
   • Calculation of inputs and outputs in a system

   Hint

   Consider the meaning of balance.

4. 4.

   True or False: The partitioning constant indicates solubility.

   • True
   • False

   Hint

   Think about what the partitioning constant tells us.

5. 5.

   Given 150 kg of a chemical with a partitioning constant of K = 10, if mixed with 500 kg of water with a solubility of 1 mg/L, how would you assess the mass balance if the remaining mass in solid compounds is known to be 40 kg?

   Hint

   Be sure to account for all phases.

6. 6.

   If in a remediation scenario 80 kg of chemical X is found in water, 50 kg in solids, and you know that 20 kg is left undissolved, verify if calculations are balanced and what can be deduced.

   Hint

   What does the left-over undissolved mass tell you?