# Sulfur Trioxide Equilibrium

Chemistry Level 4

The oxidation of sulfur dioxide in burner gas to sulfur trioxide is important in the production of sulfuric acid. However, the conversion to sulfur dioxide decreases as temperature increases.

An equimolar mixture of $$\ce{S{ O }_{ 2 }}$$ and $$\ce{{ O }_{ 2} }$$ was allowed to react in a rigid cylindrical vessel. The initial total pressure is $$1 \quad bar$$. The reaction was carried out isothermally and the final pressure was taken at varying temperatures:

 $$T (^\circ C)$$ $${ P }_{ final } (bar)$$ 500 0.758 550 0.769 600 0.789 650 0.817 700 0.851

Determine the experimental standard entropy of the reaction in $$\frac{J}{mol\quad K}$$. Estimate your answer to two decimal places.

Notes:

• The reference-state partial pressure is 1 bar.

• Assume the universal gas constant $$R=8.314\frac{J}{mol\quad K}$$.

• Assume that the standard enthalpy and entropy of the reaction are temperature-independent.

• Use linear regression in solving this problem.

• Reaction must be based from one mole of sulfur dioxide.

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