The value of ΔG° at 25 °C for the formation of POCl₃ from its constituent elements, P₂ (g) + O₂ (g) + 3Cl₂ (g) → 2POCl₃ (g)
Is ________ kJ/mol.

Question

The value of ΔG° at 25 °C for the formation of POCl₃ from its constituent elements, P₂ (g)+ O₂ (g)+ 3Cl₂ (g)→ 2POCl₃ (g) Is ________ kJ/mol.

Quizplus · Accepted Answer

The standard free energy change for the formation of POCl3 from its constituent elements can be calculated using the standard free energies of formation of the reactants and products. The standard free energy of formation of a compound is the change in free energy when one mole of the compound is formed from its constituent elements in their standard states. The standard state of a gas is 1 atm pressure, and the standard state of a solid or liquid is the pure substance at 1 atm pressure.The standard free energy of formation of POCl3 is -1108.7 kJ/mol. The standard free energy of formation of P2(g) is 0 kJ/mol, the standard free energy of formation of O2(g) is 0 kJ/mol, and the standard free energy of formation of Cl2(g) is 0 kJ/mol. Therefore, the standard free energy change for the formation of POCl3 from its constituent elements is:ΔG° = 2(-1108.7 kJ/mol) - (0 kJ/mol + 0 kJ/mol + 3(0 kJ/mol)) = -1108.7 kJ/molTherefore, the correct answer is A.

The Value of ΔG° at 25 °C for the Formation