If Radius (r) = 125 pm and z = 4 (FCC),find the Edge length of unit cell (a) and Number of unit cells in 1 cm3 of Al = ?
Answer: 2.266 × 1024 unit cells
If Edge length (a) = 3.9231 Å or 3.9231 × 10−8 cm, Atomic weight of Pt (M)= 195.08 and
z = 4 (FCC) find the Density (d) and Atomic radius (r) = ?
Avogadro’s number = NA = 6.023 × 1023
Answer: r = 138 .7 pm
Edge length (a) = 4.049 Å, Atomic mass of Al (M) = 26.98 g/mol and z = 4 (FCC) find Density (d) = ?
Avogadro’s number = NA = 6.023 × 1023
Answer: 2.699 g/cc
A cubic solid is made of two elements P and Q. Atoms of Q are at the corners of the cube and that of P are at the bodycentre. What is the formula of the compound? What are the coordination numbers of P and Q?
Answer: The formula of the compound is PQ.The coordination number of both P and Q is 8.
The edge length of the unit cell of Ta, is 330.6 pm; the unit cell is body-centered cubic. Tantalum has a density of 16.69 g/cm3 (a) calculate the mass of a tantalum atom. (b) Calculate the atomic weight of tantalum in g/mol.
Answer: 3.015 x 10¯22 g and 181.6 g/mol
An element with density 11.2 g cm-3 forms an FCC lattice with edge length of 4 X 10-8cm. Calculate the atomic mass of the element. (Given: N = 6.022 X 1023 mol-1)
Answer: 107.9 g
Tungsten crystallizes in a body-centred cubic unit cell. If the edge of the unit cell is 316.5 pm, what is the radius of the tungsten atom?
Answer: 137.04 pm
The well known mineral fluorite is chemically calcium fluoride. It is known that in one unit cell of this mineral there are 4 Ca2+ ions and 8 F–. ions and that Ca2+ ions are arranged in a FCC lattice. The F- ions fill all tetrahedral holes in the face centred cubic lattice of Ca2+ ions. The edge of the unit cell is 5.46 X 10-8 cm in length. The density of the solid is 3.18 g cm-3. Use this information to calculate Avogadro’s number. (Molar mass of CaF2 = 78.08 g mol-1)
Answer: 6.023 X 10 23
What is the formula of a compound in which the element ‘Y’ form hep lattice and atoms of ‘X’ occupy 1/3 r“ of octahedral voids.
Answer: XY3
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 2/3rd of tetrahedral voids?
Answer: X4 Y1
Calculate the packing efficiency of a metal crystal for simple cubic lattice.
Answer: 52.4%
Why does Li Cl acquire pink colour when heated in Li vapours?
What type of semiconductor is obtained when silicon is doped with boron?
Express the relationship between atomic radius(r) and the edge length (a) of the FCC unit cell.
What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy l/3rd of tetrahedral voids?
Answer : X ⅔ : Y
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