Which of the following shows a chemical reaction in which magnesium and hydrogen sulfide are the reactants and magnesium sulfide and hydrogen are the products? a. magnesium sulfide + hydrogen → magnesium + hydrogen sulfide b. magnesium + hydrogen sulfide → magnesium sulfide + hydrogen c. magnesium + magnesium sulfide → hydrogen sulfide + hydrogen d. magnesium + hydrogen → magnesium sulfide + hydrogen sulfide

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.

What happens when the temperature of a solution increases?

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.