1. Understand the Formula:

* Allicin has the chemical formula C₆H₁₀OS₂. This tells us there are two sulfur (S) atoms in each molecule of allicin.

2. Convert Milligrams to Grams:

* 7.00 mg = 0.00700 g

3. Calculate the Molar Mass of Allicin:

* C: 6 atoms * 12.01 g/mol = 72.06 g/mol

* H: 10 atoms * 1.01 g/mol = 10.10 g/mol

* O: 1 atom * 16.00 g/mol = 16.00 g/mol

* S: 2 atoms * 32.07 g/mol = 64.14 g/mol

* Total molar mass of allicin = 162.30 g/mol

4. Calculate the Moles of Allicin:

* moles = mass / molar mass

* moles = 0.00700 g / 162.30 g/mol = 4.31 x 10⁻⁵ mol

5. Calculate the Number of S Atoms:

* We know there are 2 S atoms per molecule of allicin.

* Use Avogadro's number (6.022 x 10²³ molecules/mol) to convert moles to molecules.

* Then multiply by the number of S atoms per molecule.

* Number of S atoms = (4.31 x 10⁻⁵ mol allicin) * (6.022 x 10²³ molecules/mol) * (2 S atoms/molecule)

* Number of S atoms ≈ 5.19 x 10¹⁹ S atoms

Therefore, approximately 5.19 x 10¹⁹ S atoms are present in 7.00 mg of allicin.