To determine the number of formula units in 0.5 moles of magnesium chloride ([tex]$MgCl_2$[/tex]), we follow these steps:
1. Understand the concept of a "mole": A mole is a unit that measures the amount of substance. It is defined as the amount of any chemical substance that contains the same number of entities (such as atoms, molecules, ions, or formula units) as there are in 12 grams of carbon-12.
2. Know Avogadro's number: Avogadro's number, [tex]\(6.022 \times 10^{23}\)[/tex], represents the number of entities in one mole of a substance. This means that one mole of any substance contains [tex]\(6.022 \times 10^{23}\)[/tex] entities (e.g., atoms, molecules, or formula units).
3. Calculate the number of formula units: Given that 0.5 moles of [tex]$MgCl_2$[/tex] are present, and knowing that one mole contains [tex]\(6.022 \times 10^{23}\)[/tex] formula units, we simply multiply the number of moles by Avogadro's number to find the total number of formula units in the given sample.
[tex]\[
\text{Number of formula units} = \text{Number of moles} \times \text{Avogadro's number}
\][/tex]
[tex]\[
\text{Number of formula units} = 0.5 \text{ moles} \times 6.022 \times 10^{23} \text{ formula units/mole}
\][/tex]
4. Perform the multiplication:
[tex]\[
0.5 \times 6.022 \times 10^{23} = 3.011 \times 10^{23}
\][/tex]
Thus, there are [tex]\(3.011 \times 10^{23}\)[/tex] formula units in 0.5 moles of magnesium chloride ([tex]$MgCl_2$[/tex]).
