Question

The substance tantalum is found to crystallize in a body centered cubic unit cell and has a density of 17.01 g/cm3 using these data. Calculate the atomic radius of Tantalum in picometers

Answer #1

BCC unit cell -->

D = 17.01 g/cm3

calculate radius of Tantalum in pm

then..

recall that z = 2 for BCC

d = (z*MW) / (a^3 * N)

where:

MW = molar weight of element

a = lenght of unit cell

N = avogrados number = 6.022*10^23

d= density g/cm3

so...

substitute data

17.01 = (2*180.94788) / (a^3 * (6.022*10^23))

solve for a

a = 3.28*10^-8 cm

Note that this is NOT the radius

this is the lenght if the unit cell

the unit cell and radius can be related as:

r = sqrt(3) * a / 4

so

r = sqrt(3) * a / 4

r = sqrt(3)*(3.28*10^-8)/4

r = 1.420281*10^-8 cm

r = 1.420281*10^-10 m --> to pico by 10^12

r = 142.03 pm

Chromium crystallizes in a body-centered cubic unit cell with an
edge length of 2.885 Å.
(a) What is the atomic radius (in Å) of chromium in this
structure?
____ Å
(b) Calculate the density (in g/cm3) of chromium.
____ g/cm3

An unknown metal is found to have a density of 7.8748 g/cm3 and
to crystallize in a body-centered cubic lattice. The edge of the
unit cell is found to be 0.28864 nm . Calculate the atomic mass of
the metal.

Niobium has a density of 8.57 g/cm3 and crystallizes
with the body-centered cubic unit cell. Calculate the radius of a
niobium atom.

An unknown metal is found to have a density of 7.1800 g/cm3 and
to crystallize in a body-centered cubic lattice. The edge of the
unit cell is found to be 0.28864 nm .
Calculate the atomic mass of the metal.
please show all formulas and units!

The substance calcium is found to crystallize
in a cubic lattice, with an edge length of 556.0
pm. If the density of solid calcium is
1.549 g/cm3, how many
Ca atoms are there per unit cell?
Your answer should be an integer:______ atoms

A hypothetical metal crystallizes with the face-centered cubic
unit cell. The radius of the metal atom is 184 picometers and its
molar mass is 195.08 g/mol. Calculate the density of the metal in
g/cm3.

An element crystallizes in a body-centered cubic lattice. The
edge of the unit cell is 3.37 Å in length, and the density of the
crystal is 7.88 g/cm3 .
Calculate the atomic weight of the element.
Express the atomic weight in grams per mole to three significant
digits.

A metal (FW 243.7 g/mol) crystallizes into a body-centered cubic
unit cell and has a radius of 1.86 Å. What is the density of this
metal in g/cm3?

What is the molar mass of an element that crystallizes in a
body-centered cubic unit cell with a density equal to 0.971
g/cm3 and radius of 1.853 A?

Gold crystallizes is a face-centered cubic unit cell.
Its density is 19.3 g/cm3
. Calculate the atomic radius of
gold in picometer.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 16 minutes ago

asked 39 minutes ago

asked 52 minutes ago

asked 59 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago