Answer:
3.96 × 10⁻³ mol Pb
Explanation:
Step 1: Find molar mass
Pb (Lead) - 207.2 g/mol
Step 2: Use Dimensional Analysis
[tex]0.821 \hspace{2} g \hspace{2} Pb(\frac{1 \hspace{2} mol \hspace{2} Pb}{207.2 \hspace{2} g \hspace{2} Pb} )[/tex] = 0.003962 mol Pb
Step 3: Simplify
We have 3 sig figs
0.003962 mol Pb ≈ 0.00396 mol Pb
0.00396 mol Pb = 3.96 × 10⁻³ mol Pb