What is the mass, in grams, of 202 atoms of iron (Fe)? (1 mol of Fe has a mass of 55.85 g; Avogadro's number is 6.022 × 10^{23} atoms/mol.)

• A. 6.73 × 10^{-22} g
• B. 1.87 × 10^{-20} g
• C. 5.58 × 10^{-19} g
• D. 1.12 × 10^{-18} g

Answer: (B)

Verified step by step guidance

1. Identify the given information: number of iron atoms (202 atoms), molar mass of iron (55.85 g/mol), and Avogadro's number (6.022 \times 10^{23} atoms/mol).
2. Calculate the number of moles of iron atoms using the formula: \(\text{moles} = \frac{\text{number of atoms}}{\text{Avogadro's number}} = \frac{202}{6.022 \times 10^{23}}\).
3. Use the molar mass to find the mass of the given moles of iron: \(\text{mass} = \text{moles} \times \text{molar mass} = \left(\frac{202}{6.022 \times 10^{23}}\right) \times 55.85\) g.
4. Perform the multiplication and division carefully to maintain the correct order of magnitude and units.
5. Express the final answer in scientific notation to match the format of the provided options.