Question

A chip used in a microcomputer contains 5.74 × 10^-3g of silicon.

Calculate the number of silicon atoms in the chip

Answer 1

Molar mass of silicon = 28 g
∵ 28 g of silicon contain 6.022×10²³atoms
∴ 5.74×10^-3g of silicon contain 
$\frac{6.022×10^{23}}{28}$ ×5.74×10^-3
=1.23451 × 10²⁰ atoms