Aspherical ball of lead has a diameter of 2.5 cm . what is the mass of the sphere if lead has a density of 11.34 g/cm3? (the volume of a sphere is (43)πr3 where r is the radius.)

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

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.