Question

Total number of diamond unit cells in 1.2 gm of diamond sample is:

• A. $6.0\times {10}^{21}$
• B. $6.0\times {10}^{22}$
• C. $7.5\times {10}^{21}$
• D. $5.0\times {10}^{22}$

Answer 1

The correct option is C $7.5\times {10}^{21}$

No. of moles in $1.2gm$ diamond= $\frac{1.2}{12}=0.1$ moles

No . of atoms of $C$= $0.1\times N_A=6.022\times {10}^{22}$

In one unit cell of diamond $8$ $C$ atoms are present

$⟶$ $Numberofunitcells=\frac{6.022\times {10}^{22}}{8}=7.5\times {10}^{21}$