To calculate the number of moles of NaCl when given the number of formula units, we use Avogadro's number, which is [tex]\( 6.022 \times 10^{23} \, \text{units/mol} \)[/tex]. Avogadro's number tells us how many formula units are present in one mole of a substance.
Here’s the step-by-step procedure to solve the problem:
1. Identify the given values:
- Number of formula units = [tex]\( 3.84 \times 10^{21} \)[/tex]
- Avogadro's number = [tex]\( 6.022 \times 10^{23} \, \text{units/mol} \)[/tex]
2. Formula to find the number of moles:
The number of moles can be determined by using the formula:
[tex]\[
\text{Number of moles} = \frac{\text{Number of formula units}}{\text{Avogadro's number}}
\][/tex]
3. Substitute the given values into the formula:
[tex]\[
\text{Number of moles} = \frac{3.84 \times 10^{21}}{6.022 \times 10^{23}}
\][/tex]
4. Perform the division:
[tex]\[
\text{Number of moles} = 0.006376619063434075
\][/tex]
5. Conclusion:
The number of moles of [tex]\( \text{NaCl} \)[/tex] in [tex]\( 3.84 \times 10^{21} \)[/tex] formula units is approximately [tex]\( 0.00637 \)[/tex] moles (rounding to five significant figures).
Therefore, you have [tex]\( 0.006376619063434075 \)[/tex] moles of [tex]\( \text{NaCl} \)[/tex] when you start with [tex]\( 3.84 \times 10^{21} \)[/tex] formula units.
