chemistry
posted by Tokey .
This problem is from my chemistry book and I am having a little trouble with the intermediary steps:
Barium metal crystallizes in a body centered cubic lattice (atoms at lattice points only)
The unit cell edge length is 502 pm, and the density of the metal if 3.5g/cm^3. (molar mass Ba= 137.327)
Calculate Avogadros Number.
(Hint: first calc the vol. occupied by 1 mol of Barium atoms in the unit cell, then calc the volume occupied by one Ba atom in the unit cell. Assume that 68% of unit cell is occupied by Ba atoms)
I know that V=edge length cubed (must convert from pm to cm), that there are two total spheres in a bcc unit cell and that Volume= mass/density. Im assuming the volume of 1 mole of Barium is 68% of the total volume, but how do I calc the volume occupied by 1 atom if i am trying to solve for Avogadros number?

The edge length is 502 pm (convert to cm), then a*(3)^{1/2} = 4r where r is the radius of the atom. The volume of the atom is V = (4/3)*pi*r^{3}
Respond to this Question
Similar Questions

Inorganic Chemistry
The atoms in barium metal are arranged in a body centered cubic unit cell. Calculate the radius of a barium atom in A if the density of barium is 3.50g/cm3. The atomic weight of barium is 137.34. The atoms in barium metal are arranged … 
Chemistry
The unit cell with all sides the same length and all angles equal to 90 degrees that has lattice points only at the corners is called monoclinic bodycentered cubic primative cubic facecentered cubic spherical cubic 
chemistry help!
Hello, I am having problem with two lab questions and was wondering if someone can help! 1. Calculate the percentage of the empty space in a facecentered cubic lattice, and show that it does not depend on the edge length of the unit … 
chemistry
Hello, I am having problem with two lab questions and was wondering if someone can help! 1. Calculate the percentage of the empty space in a facecentered cubic lattice, and show that it does not depend on the edge length of the unit … 
Chemistry
An element crystallizes in a bodycentered cubic lattice. The edge of the unit cell is 3.5 Angstrom, and the density of the crystal is 7.39g/cm^3. Calculate the atomic weight of the element. A= ? 
chemistry
Vanadium crystalizes in a body centered cubic lattice (the V atoms occupy only the lattice points) how many V atoms are present in a unit cell? 
chemistry
You are given a small bar of an unknown metal, X. You find the density of the metal to be 11.7 g/cm3. An Xray diffraction experiment measures the edge of the unit cell as 5.12 angstroms. Assuming the metal crystallizes in a facecentered … 
AP Chemistry
iron has a density of 7.86 g/cm3 and crystallizes a body centered cubic lattice. Show that only 68% of a body centered lattice is actually occupied by atoms, and determine the atomic radius of iron 
Chemistry
An element crystallizes in a bodycentered cubic lattice. The edge of the unit cell is 2.77 , and the density of the crystal is 8.65 . Find the atomic weight of the element. 
college chem
europium crystallizes in a bodycentered cubic cell (the Eu atoms occupy only lattice points). calculate the mass of the unit cells