Consider the following data for the reaction X₂(g) + Y₂(g) 2XY(g) at 600 K . The _r G^ (in kJ mol ⁻¹ ) for the reaction is : Compound _f H^ _ 600K (kJ mol ⁻¹ ) S^ _ 600K (J mol ⁻¹ K ⁻¹ ) XY(g) 42 200 X₂(g) 8 140 Y₂(g) 80 250

Step-by-step solution

The given reaction is X₂(g) + Y₂(g) 2XY(g) . The standard enthalpy of reaction, _r H^ , is calculated as: _r H^ = _f H^ ( products ) - _f H^ ( reactants ) _r H^ = 2 _f H^ (XY) - [ _f H^ (X₂) + _f H^ (Y₂)] _r H^ = 2(42) - (8 + 80) = 84 - 88 = -4 kJ mol ⁻¹ The standard entropy of reaction, _r S^ , is calculated as: _r S^ = S^ ( products ) - S^ ( reactants ) _r S^ = 2 S^ (XY) - [S^ (X₂) + S^ (Y₂)] _r S^ = 2(200) - (140 + 250) = 400 - 390 = 10 J K ⁻¹ mol ⁻¹ Converting _r S^ to kJ K ⁻¹ mol ⁻¹ : _r S^ = 10 1000 = 0.01 kJ