Question
Water molecules around a hydrophobic molecule are (more) structured in a sense that their multiplicity W reduces from 6 to 3 (at or around room temperature).
(a) What is an entropy change of such a water molecule? What is corresponding free energy change?
(b) Assume n is the number of water molecules adjacent to a hydrophobic molecule. What is total free energy change due to water structuring?
(c) Imagine that 10 water molecules cover an area of 1nm2 around the hydrophobic molecule. What is free energy cost for exposing a hydrophobic molecule per area? Reply this in units of kBT/nm2.
(d) Using your results in (a) or (b) give details why oil and water do not mix (at room temperature).