Question

number of Mg(OH)2 formula units in 7.40 moles of Mg(OH)2

Answer 1

7.40 moles of Mg(OH)2
Using the ratio, Multiply by the Avogadro number
\[7.40 \cancel{\text{ moles of } Mg(OH)_2} \times \frac{6.02 \times 10^{23}\text{ atoms of } Mg(OH)_2}{1\cancel{\text{ mole of } Mg(OH)_2}}=4.45 \times 10^{24} \text{ atoms of } Mg(OH)_2\]

Answer 2

Thanks. :)