NUMERICALS BASED ON DENSITY IN SOLID STATE

Gold crystallizes in a face-centered cubic lattice. If the length of the edge of the unit cell is 407 pm, calculate the density of gold as well as its atomic radius assuming it to be spherical. Atomic mass of gold=197amu.

• 19.4gm/cm³,143.9pm

• 21gm/cm³,150.1pm

• 25gm/cm³,149pm

• 18gm/cm³,160pm

The effective radius of an iron atom is 1.42 Å. It has rock salt like structure. Calculate its density (Fe=56 amu).

• 4.74g/cm³

• 3.74g/cm³

• 5.74g/cm³

• 6.74g/cm³

The edge length of NaCl unit cell is 564 pm. What is the density of NaCl in g/cm³?(N_A=6.02 X 10²³, Na=23 u and Cl=35.5u)

• 4.16g/cm³

• 2.16g/cm³

• 5.16g/cm³

• 6.16g/cm³

The compound CuCl has Zns structure and the edge length of its unit cell is 500 pm. Calculate its density (Atomic masses: Cu=63.5u, Cl=35.5 Avogardo’s constant=6.02 X 10²³ mol^-1).

• 2.16g/cm³

• 5.24g/cm³

• 7.24g/cm³

• 6.16g/cm³

KF has NaCl structure. If the distance between K⁺

and F^- is 269 pm, find the density of KF (N_A= 6.02X10²³ mol^-1 , atomic masses K=39,F=19 amu )

• 32.48g/cm³

• 9.48g/cm³

• 12.48g/cm³

• 2.48g/cm³

Copper crystal has a face-centred cubic lattice structure. Atomic radius of copper atom is 128 pm. Calculate the density of copper. Atomic mass of copper=63.5u.

• 8.9g/cm³

• 22.9g/cm³

• 32.9g/cm³

• 42.16g/cm³

Calculate the density of silver which crystallizes in a face-centred cubic structure. Two distance between the nearest silver atom in this structure is 287 pm.(molar mass of Ag=107.87 g mol^-1,N_A=6.02X10²³ mol^-1).

• 4.71g/cm³

• 2.71g/cm³

• 12.71g/cm³

• 10.71g/cm³

TYPE-II CALCULATION OF EDGE/INTERIONIC DISTANCE/RADIUS FROM DENSITY

Q. The compound CuCl has Zns(cubic) structure. Its density is 3.4 g cm^-3. What is the length of the edge of the unit cell? (Atomic masses Cu=63.5, Cl=35.5).

• 478pm

• 578pm

• 278pm

• 178pm

CsCl have cubic structure.Its density is 3.99gm/cm^3. What is distance between Cs⁺ and Cl^- [At.mass of Cs=133]

• 257pm

• 457pm

• 357pm

• 557

The density of a face centred cubic element (atomic mass=60.2 amu) is 6.25 g cm^-3. Calculate the length of the edge of the unit cell.

• 400pm

• 300pm

• 200pm

• 100pm