Advertisements
Advertisements
Question
An element crystallizes in fcc lattice with a cell edge of 300 pm. The density of the element is 10.8 g cm-3. calculate the number of atoms in 108 g of the element.
Solution
The volume of a unit cell
=(300 pm)3
=(3.00 × 10-8 cm)3
= 2.7 × 10-23 cm3
Volume of 108 g of element
= `"mass"/"density"= (108 "g")/(10.8 "cm"^-3) = 10 "cm"^3`
Number of unit cells in this volume =`(10"cm"^3)/(2.7xx10^-23 "cm"^3//"unit cell")= ( 10^24)/(2.7) "Unit cells"`
Since each FCC unit cell contains 4 atoms, therefore the total number of atoms in 108 g 4 atoms/unit cell × `10^24/2.7`unit cell
= 1.48 × 1024 atoms
APPEARS IN
RELATED QUESTIONS
Silver crystallises in FCC structure. If density of silver is 10.51 gcm-3, calculate the volume of unit cell. [Atomic mass of slive (Ag) = 108 gm-1]
Niobium crystallises as body centred cube (BCC) and has density of 8.55 Kg / dm-3 . Calculate the attomic radius of niobium.
(Given : Atomic mass of niobium = 93).
An element crystallizes in a f.c.c. lattice with a cell edge of 250 pm. Calculate the density if 300 g of this element contains 2 × 1024 atoms.
An element with density 2.8 g cm–3 forms a f.c.c. unit cell with edge length 4 x 10–8 cm. Calculate the molar mass of the element.
(Given : NA = 6.022 x 1023 mol –1)
A metal crystallises into two cubic faces namely face centered (FCC) and body centered (BCC), whose unit cell edge lengths are 3.5 Å and 3.0 Å respectively. Find the ratio of the densities of FCC and BCC.
An element with density 11.2 g cm–3 forms a f.c.c. lattice with edge length of 4 × 10–8 cm.
Calculate the atomic mass of the element.
(Given : NA = 6.022 × 1023 mol–1)
Represent a cell consisting of Mg2+ | Mg half cell and Ag+
| Ag half cell and write the cell reaction.
( `"E"_("Ag")^° = 0.799 "V", "E"_("Mg")^° = - 2.37 "V"`)
An element crystallizes in fcc lattice with a cell edge of 300 pm. The density of the element is 10.8 g cm−3. Calculate the number of atoms in 108 g of the element.
A unit cell of NaCl has 4 formula units. Its edge length is 0.50 nm. Calculate the density if molar mass of NaCl = 58.5 g/mol.
Tetragonal crystal system has the following unit cell dimensions
