What is the heat of reaction when sulfur dioxide reacts with oxygen to form sulfur trioxide? 2so2(g) + o2(g) → 2so3(g) (∆hf0 so2(g) = –298.8 kj/mol; ∆hf0 so3(g) = –395.7 kj/mol) –201.9 kj –492.6 kj –694.5 kj –193.8 kj?

Answer : The enthalpy change for this reaction is -193.8 kJ.

Solution :

The balanced chemical reaction is,

The expression for enthalpy change is,

where,

n = number of moles

(as heat of formation of substances in their standard state is zero

Now put all the given values in this expression, we get

Therefore, the enthalpy change for this reaction is, -193.8 KJ