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A pure crystalline substance forms a face-centred cubic lattice with a unit cell edge length of 400 pm. If the crystal's density is 8 g cm⁻³, how many atoms are contained in 256 g of this crystal, expressed as N × 10²⁴? Determine the value of N.

1. 1
2. 2
3. 3
4. 4

Correct answer: 2

Solution

The correct answer is obtained by using the formula for density, which is mass per unit volume, and the given unit cell edge length to calculate the number of atoms in 256 g of the crystal, resulting in the value of N being 2.

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