Determine the number of grams of H2 formed when 250.0 mL of 0.743 M HCl solution reacts with 3.41 x 10^23 atoms of Fe according to the following reaction: 2 HCl(aq) + Fe(s) → H2(g) + FeCl2(aq).

• A. 0.050 grams
• B. 0.100 grams
• C. 0.025 grams
• D. 0.075 grams

Answer: (A)

Verified step by step guidance

1. Calculate the moles of HCl in the solution using the formula: \( \text{moles of HCl} = \text{Molarity} \times \text{Volume in Liters} \). Convert 250.0 mL to liters by dividing by 1000.
2. Determine the moles of Fe using Avogadro's number: \( \text{moles of Fe} = \frac{3.41 \times 10^{23} \text{ atoms}}{6.022 \times 10^{23} \text{ atoms/mol}} \).
3. Use the stoichiometry of the balanced chemical equation \( 2 \text{HCl} + \text{Fe} \rightarrow \text{H}_2 + \text{FeCl}_2 \) to find the limiting reactant. Compare the mole ratio of HCl to Fe.
4. Calculate the moles of \( \text{H}_2 \) produced using the stoichiometry of the reaction. For every 2 moles of HCl, 1 mole of \( \text{H}_2 \) is produced.
5. Convert the moles of \( \text{H}_2 \) to grams using the molar mass of hydrogen gas \( \text{H}_2 \), which is approximately 2.02 g/mol. Use the formula: \( \text{grams of } \text{H}_2 = \text{moles of } \text{H}_2 \times 2.02 \text{ g/mol} \).