Question

A silicon (at. wt. = 28) chip, used in an integrated circuit of a computer, has a mass of 5.68 mg. How many silicon atoms are present in this chip?

• A. $2.02\times {10}^{-4}$
• B. $1.22\times {10}^{20}$
• C. $1.22\times {10}^{39}$
• D. $122\times {10}^{20}$

Answer 1

The correct option is B $1.22\times {10}^{20}$

$\left(5.68mg\right)\times \frac{1g}{1000mg}\times \frac{1molSi}{28g}\times (6.022\times {10}^{23}atoms/1mol)=1.22\times {10}^{20}$ Si atoms