Consider the reaction 2 H ₂ S (g) + 3 O ₂(g) 2 H ₂ O (l) + 2 SO ₂(g) The magnitude of enthalpy change for the reaction in kJ mol ⁻¹ is ________. (Nearest integer) Given: _fH^ ( H ₂ S ) = -20.1 kJ mol ⁻¹ _fH^ ( H ₂ O ) = -286.0 kJ mol ⁻¹ _fH^ ( SO ₂) = -297.0 kJ mol ⁻¹

Step-by-step solution

The standard enthalpy of reaction is given by: _r H^ = _f H^ ( products ) - _f H^ ( reactants ) For the given reaction: 2 H ₂ S (g) + 3 O ₂(g) 2 H ₂ O (l) + 2 SO ₂(g) _r H^ = [2 _f H^ ( H ₂ O , l) + 2 _f H^ ( SO ₂, g)] - [2 _f H^ ( H ₂ S , g) + 3 _f H^ ( O ₂, g)] Substituting the given values: _r H^ = [2(-286.0) + 2(-297.0)] - [2(-20.1) + 3(0)] _r H^ = [-572.0 - 594.0] - [-40.2] _r H^ = -1166.0 + 40.2 = -1125.8 kJ mol ⁻¹ The magnitude of the enthalpy change is 1125.8 kJ mol ⁻¹ . Rounding to the nearest integer, we