Question

how many grams of mg(oh)2 are in 7.5 x 10^23 formula units (f.un.) mg(oh)2? 7.5 x 10^23 f.un. 1 mole 58.32 g 6.02 x 10^23 f.un. 1 mole 73 g 58 g 145 g

Explanation:

Step1: Convert formula units to moles

Use the conversion factor \(1\ \text{mole} = 6.02\times10^{23}\ \text{f.un.}\).

$$ \frac{7.5\times 10^{23}\ \text{f.un.}}{6.02\times 10^{23}\ \text{f.un./mole}} $$

Step2: Convert moles to grams

Use the molar mass \(58.32\ \text{g/mole}\).

$$ \frac{7.5\times 10^{23}}{6.02\times 10^{23}}\times58.32\ \text{g} $$

Calculate \(\frac{7.5}{6.02}\approx1.246\), then \(1.246\times58.32\approx72.77\approx73\ \text{g}\)

Answer:

\(73\ \text{g}\)