europium crystallizes in a body-centered cubic cell (the Eu atoms occupy only lattice points). calculate the mass of the unit cells
2*atomic mass Eu/6.02E23 = ?
To calculate the mass of the unit cell, we first need to know the crystal structure of europium and its atomic mass. Europium crystallizes in a body-centered cubic (BCC) lattice, which means that there is an atom at each of the eight corners and one atom in the center of the cube. Only the lattice points are occupied, so we need to consider only the number of atoms at the lattice points.
The formula unit of europium is Eu, and its atomic mass is approximately 152.0 g/mol. Since each unit cell consists of one Eu atom, we just need to find the mass of one Eu atom.
The formula mass or molar mass of a substance can be calculated by adding up the atomic masses of all the constituent atoms. In the case of europium with an atomic mass of 152.0 g/mol, the mass of one Eu atom can be calculated as:
Mass of one Eu atom = Atomic mass of Eu / Avogadro's number
Avogadro's number is approximately 6.022 x 10^23 mol^-1.
So, the mass of one Eu atom is:
Mass of one Eu atom = 152.0 g/mol / (6.022 x 10^23 mol^-1) = (approximately) 2.526 x 10^-22 g
Therefore, the mass of the unit cell, which consists of one Eu atom, is approximately 2.526 x 10^-22 g.