How many nitrogen atoms are present in 15.0 grams of Pb(NO2)2?

• A. 9.84 × 10^{22}
• B. 3.94 × 10^{23}
• C. 1.97 × 10^{23}
• D. 6.02 × 10^{22}

Answer: (C)

Verified step by step guidance

1. Determine the molar mass of Pb(NO2)2 by adding the atomic masses of each element: Pb, N, and O. Use the atomic masses from the periodic table (Pb ≈ 207.2 g/mol, N ≈ 14.01 g/mol, O ≈ 16.00 g/mol). Calculate the total molar mass as: \(\text{Molar mass} = 207.2 + 2 \times (14.01 + 2 \times 16.00)\) g/mol.
2. Calculate the number of moles of Pb(NO2)2 in 15.0 grams using the formula: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{15.0}{\text{molar mass}}\) mol.
3. Identify the number of nitrogen atoms per formula unit of Pb(NO2)2. Since there are 2 NO2 groups, and each contains 1 nitrogen atom, there are 2 nitrogen atoms per formula unit.
4. Calculate the total number of nitrogen atoms by multiplying the moles of Pb(NO2)2 by Avogadro's number (\$6.022 \times 10^{23}\( atoms/mol) and then by the number of nitrogen atoms per formula unit: \)\text{N atoms} = \text{moles} \times 6.022 \times 10^{23} \times 2$.
5. Express the final answer in scientific notation to match the format of the options given.