Bethany has a fish tank at her house. she uses the following data table to keep track of the nitrate and phosphate levels in the tank.

month nitrates phosphates
january 8.0 mg/l 0.010 mg/l
february 8.1 mg/l 0.010 mg/l
march 7.9 mg/l 0.009 mg/l
april 9.2 mg/l 0.012 mg/l
may 9.7 mg/l 0.020 mg/l
june 9.9 mg/l 0.029 mg/l
july 10.6 mg/l 0.032 mg/l
august 10.8 mg/l 0.038 mg/l
september 11.0 mg/l 0.036 mg/l

bethany notices that the fish tank is gradually filling with algae. based on the data she has collected, when did the problem most likely start? explain.

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.