At 25°C, 50 g of iron reacts with HCl to form FeCl . The evolved hydrogen gas expands against a cons — Thermodynamics and Thermochemistry Chemistry Question
Question
At 25°C, 50 g of iron reacts with HCl to form FeCl . The evolved hydrogen gas expands against a constant pressure of 1 bar. The work done by the gas during this expansion is (Round off to the Nearest Integer). [Given: R=8.314 J mol K . Assume, hydrogen is an ideal gas] [Atomic mass of Fe is 55.85 u] 2 –1 –1
💡 Solution & Explanation
**Step 1: Write the balanced chemical equation and identify the product.** Fe + 2HCl → FeCl₂ + H₂↑ (Note: The question states "FeCl" but the balanced equation produces FeCl₂ with H₂ gas) **Step 2: Calculate moles of iron reacted.** Moles of Fe = 50 g ÷ 55.85 g/mol = 0.895 mol **Step 3: Calculate moles of H₂ produced.** From the stoichiometry: 1 mol Fe produces 1 mol H₂ Moles of H₂ = 0.895 mol **Step 4: Find the volume of H₂ at standard conditions using ideal gas law.** PV = nRT V = nRT/P = (0.895 mol × 8.314 J mol⁻¹ K⁻¹ × 298 K) / (1 × 10⁵ Pa) V = 2217.5 / 10⁵ = 0.02218 m³ **Step 5: Calculate work done by gas expansion at constant pressure.** W = PΔV = (1 × 10⁵ Pa) × (0.02218 m³) W = 2218 J Therefore, the answer is 2218.00.