To determine the number of formula units in 35.0 grams of [tex]\( \text{KNO}_3 \)[/tex], follow these steps:
1. Determine the number of moles of [tex]\( \text{KNO}_3 \)[/tex]:
The molar mass of [tex]\( \text{KNO}_3 \)[/tex] is given as 101.11 g/mol.
Using the formula for moles (number of moles = mass / molar mass):
[tex]\[
\text{moles} = \frac{35.0 \text{ g}}{101.11 \text{ g/mol}} \approx 0.3462 \text{ moles}
\][/tex]
2. Convert moles to formula units using Avogadro's number:
Avogadro's number ([tex]\(6.022 \times 10^{23}\)[/tex]) tells us how many entities (atoms, molecules, formula units, etc.) are in one mole of a substance.
To find the number of formula units:
[tex]\[
\text{formula units} = \text{moles} \times \text{Avogadro's number}
\][/tex]
Substituting the values:
[tex]\[
\text{formula units} = 0.3462 \text{ moles} \times 6.022 \times 10^{23} \approx 2.08 \times 10^{23} \text{ formula units}
\][/tex]
So, in 35.0 grams of [tex]\( \text{KNO}_3 \)[/tex], there are approximately [tex]\(2.08 \times 10^{23}\)[/tex] formula units of [tex]\( \text{KNO}_3 \)[/tex].
