Question

Electric generating plants transport large amounts of hot water through metal pipes, and oxygen dissolved in the water can cause a major corrosion problem. Hydrazine (N₂H₄) added to the water avoids the problem by reacting with the oxygen: N₂H₄(aq) + O₂(g) → N₂(g) + 2 H₂O(l)

About 4 x10⁷ kg of hydrazine is produced every year by reacting ammonia with sodium hypochlorite in the Raschig process:

2 NH₃(aq) + NaOCl(aq) → N₂H₄(aq) + NaCl(aq) + H₂O(l) Δ_rH° = −151 kJ

(a) If Δ_fH°  of NaOCl(aq) = −346 kJ/mol, find Δ_fH°  of N₂H₄(aq) given that Δ_fH° [NH₃(aq)] = −80.83 kJ/mol, Δ_fH° [NaOCl(aq)] = −346 kJ/mol, Δ_fH° [Na⁺(aq)] = −239.66 kJ/mol, Δ_fH° [Cl⁻(aq)] = −167.46 kJ/mol and Δ_fH° [H₂O(l)] = −285.840 kJ/mol.

______ kJ/mol

b) What is the heat released when aqueous N₂H₄ is added to 6.00 × 10³ L of plant water that is 2.50 × 10⁻⁴ mol/L O₂? Enter your answer in scientific notation.

____× 10___ kJ

Answer 1