please help me with this chem question....?

Question

Barium crystalizes in a body-centered cubic system with atoms at all lattice points and an edge length of 5.02 angstroms. Calculate its density in g/cm3.

please explain if u can how u got the answer. thanks

Answer 1

I can only get you started. Density is g/cu cm. In a body-centered cubic, you have one atom in the center of the cube. At the eight vertices of the cube, you have the atoms that are shared with adjoining cubes. Each cube shares a vertex atom with eight other adjoining cubes. (Imagine stacking four cubes on a bottom layer, four more cubes in a top layer, and considering that the corner in the very center has one atom divided by 8.) Any one cube thus has eight corners, 1/8 atom per corner, so 1 atom per cell. So that plus the center atom makes two atoms per cell. There are 6.02x10^23 atoms per gram atom of Ba. There is 137g/gram atom of Ba. The side of a cube is 5.02A. An A is 10^-8cm. If you cube 5.02x10^-8cm, you get the volume of the cube in cu cm. You already have the grams.