Question

A chip used in a microcomputer contains 5.74 x 10-3g of silicon. Calculate the number of silicon atoms in the chip. [ Si = 28; Avogadros constant 6.02 x 1023]

Answer 1

$m = 5.74×10^{-3}g\\ \textsf{molar mass} = 28g/mol\\ \textsf{number of moles} = \dfrac{5.74×10^{-34}}{28} = 2.05×10^{-4}\ moles$

1 mole of Si = 6.02 × 10²³ atoms

2.05 × 10^-4 moles of Si = x

x = $\dfrac{2.05×10^{-4}×6.02×10^{23}}1$ = 1.234 × 10²⁰ atoms.

Therefore, the chip has 1.234 × 10²⁰ atoms.