A researcher measures the equilibrium separation between two flat hydrophilic mica plates in a solution of non-ionic surfactant. When the surfactant concentration is below CMC the surfaces touch at 0 nm distance without any separation (i. e., there is no surfactant adsorption and repulsion)

a) The researcher increases the surfactant concentration much above CMC and finds out that the system has equilibrium separations at 0 nm, 4 nm, 8 nm, 12 nm and some at larger distances. Draw schematics and explain the reason for this effect.
b) The researcher hydrophobizes the mica surfaces and again dips them in the first solution with surfactant concentration below CMC. When these surfaces are brought in contact, they remain separated at a distance of 4 nm (no equilibria at larger separations). Draw a schematic and explain the reason for this observation with hydrophobic surfaces.

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

If 1.8 l of water is added to 2.5l of a 7.0 m koh solution, what is the molarity of the new solution

Adepositional also feature that forms where a stream enters a lake or an ocean is a