You wish to measure the iron content of the well water on the new property you are about to buy. you prepare a reference standard fe3 solution with a concentration of 6.35 ă— 10-4 m. you treat 10.0 ml of this reference with hno3 and excess kscn to form a red complex, and dilute the reference to 55.0 ml. the diluted reference is placed in a cell with a 1.00-cm light path. you then take 35.0 ml of the well water, treat with hno3 and excess kscn, and dilute to 100.0 ml. this diluted sample is placed in a variable pathlength cell. the absorbance of the reference and the sample solutions match when the pathlength is 4.40 cm. what is the concentration of iron in the well water? for each solution, the zero is set with a blank.

Which orbitals form a pi bond? a.the s orbital and three p orbitals b.the s orbital and two p orbitals c.overlapping p orbitals d.overlapping hybrid orbitals

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion

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.