Copper crystallizes in a face-centered cubic unit cell. The density of copper is 8.94 g/cm³. Calculate the length of the edge of the unit cell in pm. A) 461 pm B) 361 pm C) 261 pm D) 161 pm E) None of the above

Question

Quizplus · Accepted Answer

1. The face-centered cubic unit cell of copper contains atoms at the corners and in the center of each face of the cube.
2. The unit cell edge length (a) can be calculated using the formula: 
a = [(4 * atomic mass)/(density * Avogadro's number)]^(1/3)
3. The atomic mass of copper is 63.55 g/mol.
4. Avogadro's number is 6.022 x 10^23.
5. Substituting the values in the formula, we get:
a = [(4 * 63.55)/(8.94 * 6.022 x 10^23)]^(1/3) = 3.61 x 10^-8 cm = 361 pm. 
Therefore, the best choice is B, with a unit cell edge length of 361 pm.

Copper Crystallizes in a Face-Centered Cubic Unit Cell