Why do sharks have high urea concentrations?

Why do we omit the concentrations of pure liquids and solids from the mass action expression?

• Why do we omit the concentrations of pure liquids and solids from the mass action expression of heterogeneous reactions? Select all that apply. a) It is difficult to determine their concentrations. b) When mass is gained or lost by a pure liquid or pure solid, its concentration remains constant. c) When mass is gained or lost by a pure liquid or pure solid, its concentration varies. d) Their concentrations are incorporated into the numerical value of the mass action expression. e) None of these.

• Answer:

  EDITED: Sorry about that, I read over the part that said select all that apply. The answer is B and D. Guess this is a great example of why you always read the question carefully.