As water evaporates from an open container at 40°c, which one of the following is true?
(a) the water becomes warmer as the kinetic energy of the liquid water molecules
increases.
(b) the water molecules decompose into hydrogen and oxygen molecules.
(c) the water molecules return to the surface as fast as they leave.
(d) the water vapour molecules have greater kinetic energy than the liquid water
molecules.

What royal scientist used the 29th day of frozen vapor to encounter elements for mastering new culinary creations?

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.

How do you know when a chemical reaction has occurred