Which of the following would be a warning sign that information about a weight loss medication is not reliable science?

d.)it is made up of millions of units of a single type of compound.

a.) a chemical change is required to separate its mixed components.

b.) it is made up of millions of atoms of a single element.

c.) a physical change can separate its mixed components.

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

Express the following number in scientific notation. 0.026890 =

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.