Sodium carbonate can be made by heating sodium bicarbonate: 2NaHCO₃(s) → Na₂CO₃(s) + CO₂(g) + H₂O(g)
At 25°C, for this reaction, ΔH°_rxn = 128.9 kJ/mol and ΔG°_rxn = 33.1 kJ/mol. Above what minimum temperature will the reaction become spontaneous under standard state conditions?

Question

Quizplus · Accepted Answer

At constant pressure and temperature, ΔG°_rxn = ΔH°_rxn - TΔS°_rxn. Rearranging, we have T = (ΔH°_rxn) / (ΔS°_rxn) - (ΔG°_rxn) / (ΔS°_rxn) Substituting the values given in the problem statement, we get T = (128.9 kJ/mol) / (282.5 J/K/mol) - (33.1 kJ/mol) / (282.5 J/K/mol). Simplifying this expression, we get T = 401 K. Therefore, the reaction will become spontaneous under standard state conditions above 401 K. The correct answer is choice D.

Sodium Carbonate Can Be Made by Heating Sodium Bicarbonate: 2NaHCO3(s)

Sodium Carbonate Can Be Made by Heating Sodium Bicarbonate: 2NaHCO₃(s)