Question

You found an unknown metal sample shaped as a cube with each side measuring 2.00 cm. The cube's mass is 48.0 . Your colleague examined the mystery cube with X-ray diffraction and told you that it contains just one element arranged in a body-centered-cubic -lattice, and that the unit cell length is 304.4 pm. What element is the cube made of? Hint: determine the atomic weight and look it up in the periodic table.

My work:
2mol* 48g* 2 cm/ (6.022*10^23mol)(304.4*10^-10 cm)^3=
11.3 g
Boron

This is wrong! Could you please show me how to do this problem?

Answer 1

volume of the large cube is 2^3 = 8.0 cc
density = m/v= 48/8 = 6 g/cc

volume of unit cell = (3.044E-8 cm)^3 = 2.892E-23 cc
mass unit cell = v x d = 2.89E-23*6 = 1.69E-22
1.69E-22 = 2*atomic mass /6.022E23
Solve for atomic mass.

Answer 2

If a sugar cube measured 20cm by 20cm how much surface area would be exposed to the solvent(water)