You're asking about the standard enthalpy of formation of sulfur dioxide (SO₂), which is indeed -296.8 kJ/mol.

Here's the reaction that represents this:

S(s) + O₂(g) → SO₂(g) ΔH°f = -296.8 kJ/mol

Explanation:

* S(s): This represents solid sulfur in its standard state.

* O₂(g): This represents oxygen gas in its standard state.

* SO₂(g): This represents sulfur dioxide gas, the product of the reaction.

* ΔH°f = -296.8 kJ/mol: This indicates that the standard enthalpy change for the formation of one mole of SO₂ from its elements in their standard states is -296.8 kJ. The negative sign means the reaction is exothermic, releasing heat.

Important Note: The enthalpy of formation is always defined for the formation of one mole of the compound from its elements in their standard states at 298 K (25°C) and 1 atm pressure.