Answer :
To find out how many lithium (Li) atoms are contained in 97.9 grams of lithium, follow these steps:
1. Find the Molar Mass of Lithium:
The molar mass of lithium is approximately 6.94 grams per mole (g/mol). This value tells us how much one mole of lithium atoms weighs.
2. Calculate the Number of Moles of Lithium in 97.9 grams:
To find out how many moles you have, divide the given mass by the molar mass:
[tex]\[
\text{Number of moles} = \frac{\text{Mass of Li}}{\text{Molar mass of Li}} = \frac{97.9 \, \text{g}}{6.94 \, \text{g/mol}}
\][/tex]
3. Use Avogadro's Number to Find the Number of Atoms:
Avogadro's number is [tex]\(6.022 \times 10^{23}\)[/tex] atoms per mole. This tells us how many atoms are in one mole of any substance.
Multiply the number of moles by Avogadro's number to get the total number of atoms:
[tex]\[
\text{Number of atoms} = \text{Number of moles} \times 6.022 \times 10^{23} \, \text{atoms/mol}
\][/tex]
When you perform these calculations, you will find that there are approximately [tex]\(8.49 \times 10^{24}\)[/tex] lithium atoms in 97.9 grams of lithium. Therefore, the correct answer is:
[tex]\(8.49 \times 10^{24}\)[/tex] Li atoms
1. Find the Molar Mass of Lithium:
The molar mass of lithium is approximately 6.94 grams per mole (g/mol). This value tells us how much one mole of lithium atoms weighs.
2. Calculate the Number of Moles of Lithium in 97.9 grams:
To find out how many moles you have, divide the given mass by the molar mass:
[tex]\[
\text{Number of moles} = \frac{\text{Mass of Li}}{\text{Molar mass of Li}} = \frac{97.9 \, \text{g}}{6.94 \, \text{g/mol}}
\][/tex]
3. Use Avogadro's Number to Find the Number of Atoms:
Avogadro's number is [tex]\(6.022 \times 10^{23}\)[/tex] atoms per mole. This tells us how many atoms are in one mole of any substance.
Multiply the number of moles by Avogadro's number to get the total number of atoms:
[tex]\[
\text{Number of atoms} = \text{Number of moles} \times 6.022 \times 10^{23} \, \text{atoms/mol}
\][/tex]
When you perform these calculations, you will find that there are approximately [tex]\(8.49 \times 10^{24}\)[/tex] lithium atoms in 97.9 grams of lithium. Therefore, the correct answer is:
[tex]\(8.49 \times 10^{24}\)[/tex] Li atoms
