Question

Ice crystallises in a hexagonal lattice having the volume of unit cell as 132 * 10^-24 cm³. If the density is 0.92g/cm³ at a given temperature , then what is the number of H2O molecules per unit cell?

Answer 1

Dear Student,
GIVEN : volume = 132$\times {10}^{-24}$ cm³
Density = 0.92 g/cm³

number of H₂O molecules per unit cell =?
d=$\frac{z\times M}{N_A\times V}$
so number of water molecules (z) = $\frac{d\times N_A\times V}{M}$
putting the values we get z=4.06 approximately equal to 4
Regards!