Advertisements
Advertisements
प्रश्न
The density of iron crystal is 8.54-gram cm–3. If the edge length of the unit cell is 2.8 A° and atomic mass is 56 gram mol–1, find the number of atoms in the unit cell. (Given: Avogadro's number = 6.022x1023,1A° = 1x10-8 cm)
उत्तर
Given a = 2.8Å = `2.8 xx 10^(-8)` cm
Molar Mass = 56 gm
Density = 8.54 g cm-3
Volume = (a)3
`= (2.8 xx 10^(-8))^3`
`= 21.95 xx 10^(-24) cm^3`
Density of unit cell = `"Mass of unit cell"/"Volume of unit cell"`
∴ Mass of unit cell = density x volume
`= 21.95 xx 10^(-24) xx 8.54`
`= 187.47 xx 10^(-24)`
56 gm of Fe contains 6.022 x 1023 atoms
`187.47 xx 10^(-24)` gm Fe contain = `(6.022xx10^23 xx 187.47xx10^(-24))/56`
= `20.15xx 10^(-1)`
= 2.01
= 2
Number of atoms in unit cell is 2.
APPEARS IN
संबंधित प्रश्न
Choose the most correct answer.
In crystal lattice formed by bcc unit cell, the void volume is _______.
Choose the most correct answer.
The coordination number of atoms in bcc crystal lattice is _______.
Choose the most correct answer.
A compound forms hcp structure. Number of octahedral and tetrahedral voids in 0.5 mole of substance is respectively _______.
Answer the following in one or two sentences.
Sketch a tetrahedral void.
Answer the following in brief.
How are the spheres arranged in first layer of simple cubic close-packed structures? How are the successive layers of spheres placed above this layer?
The coordination number of spheres in the hcp lattice in three dimension is ______.
The number of octahedral voids formed in 0.5 mol of a compound forming hcp structure?
A metal crystallizes in bcc lattice with edge length 4.48 Å. The radius of the metal atom is ___________ Å.
An element crystallises in a bee lattice with cell edge of 500 pm. The density of the element is 7.5 g cm-3. How many atoms are present in 300 g of metal?
The ratio of close-packed atoms to tetrahedral holes in cubic close packing is ____________.
A metallic element crystallises in simple cubic lattice. If edge length of the unit cell is 3Å, with density 8 g/cc, what is the number of unit cells in 100 g of the metal?
(Molar mass of metal = 108 g/mol)
Xenon crystallises in fcc lattice and the edge length of unit cell is 620 pm. What is the radius of Xe atom?
The coordination number of each sphere in bcc lattice is ____________.
Which of the following is CORRECT for the two dimensional arrangement of spheres given below?
Zinc forms hcp structure. What is the number of tetrahedral voids formed in 0.3 mol of it?
The atoms of element 'Y' form hexagonal close packing and the atoms of element X occupies `3/4` th portion of the number of tetrahedral voids. The formula of the compound formed by X and Y is ____________.
Which of the following has hcp crystal structure?
What is the coordination number of cation in ionic compound if the type of hole occupied by cation is cubic?
A metallic element crystallizes in simple cubic lattice. If edge length of the unit cell is 3Å, with density 8 g/cc, what is the number of unit cells in 108 g of the metal?
(Molar mass of metal = 100 g/mol)
What is the coordination number of cation in ionic compound if the type of hole occupied by cation is octahedral?
Percentages of free space in cubic close-packed structure and in the body-centered packed structure are respectively ______.
Which metal crystallises in a simple cubic structure?
The number of octahedral sites per sphere in ccp structure is ______.
Predict the type of cubic lattice of a solid element having edge length of 400 pm and density is 6.25 g/ml.
(Atomic mass of element = 60)
