JEE Main202330 Jan 2023Evening ShiftChemistrySolid StateActual
Iron oxide FeO , crystallises in a cubic lattice with a unit cell edge length of 5 . 0 Å . If density of the FeO in the crystal is 4 . 0 g cm - 3 , then the number of FeO units present per unit cell is _____ (Nearest integer) Given : Molar mass of Fe and O is 56 and 16 g mol - 1 respectively. N A = 6 . 0 × 10 23 mol - 1
Correct answer
0
Step-by-step solution
The density of the crystal can be calculated as follows, d = Z × M N 0 × a 3 d = density Z = effective   number   of   atoms M = Molar   mass N 0 = Avogadro ' s   number a = Edge   length 4 = Z × 72 6 × 10 23 × 125 × 10 - 24 Z = 4 . 166 ≃ 4