Os-182 has a half-life of 21.5 hours. How many grams of a 10.0 gram sample will remain after exactly three half-lives?

Ineed with a, b, c, d, and e on the long answer

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.