Abed contains particles of unknown average size and average surface area. experimentally, the void fraction was determined to be 0.45. for a superficial velocity of 1.0 ft/min, the pressure drop over the packed bed was 12000lb/ft2. particles, having a density of 256.0 lb/ft3, were somewhat ‘cubic’, so the sphericity was estimated to be 0.8. what is the surface area per unit mass? what happens to this estimation if the void fraction was measured to be 0.47? what happens if the estimated sphericity is determined to be 0.77?

the answer is learned

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.