Advertisements
Advertisements
प्रश्न
Gold occurs as face centred cube and has a density of 19.30 kg dm-3. Calculate atomic radius of gold. (Molar mass of Au = 197)
Advertisements
उत्तर
Unit cell of FCC `= 1/8 xx 8 + 6 xx 1/2`
= 4 atoms
Mass of unit cell of FCC `= 4 xx 197/(6.022 xx 10^23)`
= 130.85 × 10−23 g
`rho = 19.3` g/cm−3
Volume of unit cell = `(130.85xx10^-23)/19.3`
= 6.78 × 10−23 cm3
a3 = 6.78 × 10−23
a is edge of unit cell
`a = root(3)(6.78 xx 10^(-23)`
= 4.08 × 10−8 cm
For FCC
`a = sqrt8.r`
`r = a/sqrt8`
= `(4.08 xx 10^(-8))/sqrt8`
= 1.44 × 10−8 cm
= 144 pm
APPEARS IN
संबंधित प्रश्न
A unit cell of iron crystal has edge length 288 pm and density 7.86 g.cm-3. Find the number of atoms per unit cell and type of the crystal lattice.
Given : Molar mass of iron = 56 g.mol-1; Avogadro's number NA = 6.022 x 1023.
Face centred cubic crystal lattice of copper has density of 8.966 g.cm-3. Calculate the volume of the unit cell. Given molar mass of copper is 63.5 g mol-1 and Avogadro number NA is 6.022 x 1023 mol-1
Distinguish between Hexagonal and monoclinic unit cells
Explain how much portion of an atom located at (i) corner and (ii) body-centre of a cubic unit cell is part of its neighbouring unit cell.
What is the coordination number of atoms in a cubic close-packed structure?
How can you determine the atomic mass of an unknown metal if you know its density and the dimension of its unit cell? Explain.
Explain with reason sign conventions of ΔS in the following reaction
N2(g) + 3H2(g) → 2NH3(g)
A face centred cube (FCC) consists of how many atoms? Explain
Number of types of orthorhombic unit cell is ___________.
An atom located at the body center of a cubic unit cell is shared by ____________.
An element forms a cubic unit cell with edge length 405 pm. Molar mass of this element is 2.7 × 10−2 kg/mol and its density is given as 2.7 × 103 kg/m3. How many atoms of these elements are present per unit cell?
A metal has a body-centered cubic crystal structure. The density of the metal is 5.96 g/cm3. Find the volume of the unit cell if the atomic mass of metal is 50.
Gold has a face-centered cubic lattice with an edge length of the unit cube of 407 pm. Assuming the closest packing, the diameter of the gold atom is ____________.
The empty space in the body-centered cubic lattice is ____________.
Which of the following metal(s) show(s) hexagonal close-packed structure (hcp) and which show face-centered cubic (fcc) structure?
Edge length of unit cell of chromium metal is 287 pm with a bcc arrangement. The atomic radius is of the order:
The density of a metal which crystallises in bcc lattice with unit cell edge length 300 pm and molar mass 50 g mol−1 will be:
The correct set of quantum numbers for 3d subshell is
The correct set of quantum numbers for 2p sub shell is:
Percentage of free space in body centred cubic unit cell is
If a represents the edge length of the cubic systems, i.e. simple cubic, body centred cubic and face centered cubic, then the ratio of the radii of the sphere in these system will be:-
In an ionic solid r(+) = 1.6 Å and r(−) = 1.864 Å. Use the radius ratio rule to the edge length of the cubic unit cell is ______ Å.
An element A (Atomic weight = 100) having bcc structure has a unit cell edge length 400 pm. The number of atoms in 10 g of A is ______ × 1022 unit cells.
