Reactant A diffuses and reacts within a spherical, porous catalyst. The reaction is first-order and irreversible. At zero time, the catalyst, which contains no A, is dropped into a liquid bath containing a constant concentration of A. Use a shell balance to derive the governing partial differential for the concentration c(r, t) of A within the catalyst. Also, specify the initial and boundary conditions, assuming that the mass-transfer Biot number1 is infinite

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.

Summarize possible ways in which phases of matter could combine to form a solution.

What effect does a decrease in temperature have on the overall rate of a chemical reaction? a decrease in temperature decreases . the reaction rate will