1. Lead crystallizes in a face-centered cubic unit cell with an edge length of 4
ID: 937741 • Letter: 1
Question
1. Lead crystallizes in a face-centered cubic unit cell with an edge length of 495 pm. What is the radius of a lead atom in picometers? What is the density of lead in g/cm3?
2. Aluminum has a density of 2.699 g/cm3 and crystallizes with a face-centered cubic unit cell. What is the edge length of a unit cell in picometers?
3.Tungsten crystallizes in a body-centered cubic unit cell with an edge length of 317 pm. What is the length in picometers of a unit-cell diagonal that passes through the center atom?
Explanation / Answer
1.
edgelength = a = 495 pm =
volume of the unit cell = a^3 = (495*10^(-10))^3 = 1.213*10^(-22) cm
Density = ZM/a^3 Na
= 4*207.2 /(1.213*10^(-22)*6.023*10^23)
= 11.34 g/cc
2. 2.699 = 4*27/(a^3*6.023*10^23)
a = edge length = 4.05*10^-8 cm
3. a = 317 pm
diagonal length = sqrt 3a
= (sqrt3)*317
= 549.06 pm
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.