The average atomic mass of lithium is 6.94 amu. Based on the atomic masses of the two isotopes of lithium, how do the relative abundances of the
isotopes compare?
Isotope
Atomic mass (amu)
Li-6
6.015
Li-7
7.016
A. Li-7 is slightly more abundant than Li-6.
B. They are about the same.
C. Li-6 is much more abundant than Li-7.
D. LI-7 is much more abundant than Li-6

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 many atoms of mg are present in 97.22 grams of mg? 6.022 × 1023 2.408 × 1024 4.818 × 1024 5.855 × 1025

How might this scientific phenomena be explained? a paper clip floats on water.