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How will derive the formula of density of a unit cell ? |
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Answer» Solution :Using the EDGE length of a unit cell, we can calculate the density `(rho)`of the crystal hv considering a CUBIC unit cell as follows . Density of the cell `rho=(" Mass of the unit cell")/ ("Volume of the unit cell") ""...(1)` Mass of the unit cell ={Total number of atoms belong to the unit cell } `xx`mass of one atom Mass of one atom `=("MOLAR mass"(g mol^(-1)))/("Avagardo number "(mol^(-1)))""....(2) ` `m=M/N_A""....(3)` Substitute the value (3) in (2) Mass of the unit cell `=nxxM/N_A` For a cubic unit cell , all the edge lengths are equal .i.e , a = b = C Volume of the unit cel `=axxaxxa=a^3` `:.` Density of the unit cell `=rho = (nM)/(a^3N_A)` |
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