Sulfur trioxide is manufactured industrially by sequential oxidation of elemental…

CHEMISTRY · Multi-part · A Level · Chemistry · Energetics · Energetics

Problem

Sulfur trioxide is manufactured industrially by sequential oxidation of elemental sulfur:

\text{S}(s)+\tfrac{3}{2}\,\text{O}_2(g)\longrightarrow \text{SO}_3(g)

The following reactions and their standard molar enthalpy changes are available: 1.

\text{S}(s)+\text{O}_2(g)\longrightarrow \text{SO}_2(g)\qquad \Delta H_1^{\circ}=-296.8\,\text{kJ}\,\text{mol}^{-1}

\text{SO}_2(g)+\tfrac{1}{2}\,\text{O}_2(g)\longrightarrow \text{SO}_3(g)\qquad \Delta H_2^{\circ}=-98.9\,\text{kJ}\,\text{mol}^{-1}

Steam for electric power generation is produced by capturing some of the heat released in the overall formation of

\text{SO}_3(g)

. (a) Calculate the standard molar enthalpy change for the overall formation of

\text{SO}_3(g)

from elemental sulfur and oxygen. (b) Determine the total quantity of heat released (in

\text{MJ}

) when

2.50\times10^{3}\,\text{kg}

\text{SO}_3(g)

is produced under standard conditions. (c) If

65.0\%

of the heat from part (b) is captured to convert liquid water at

100\,^{\circ}\text{C}

to steam at the same temperature, and the enthalpy of vaporization of water at

100\,^{\circ}\text{C}

40.7\,\text{kJ}\,\text{mol}^{-1}

, estimate the mass of steam that can be generated. Report the answer in metric tons (

1\,\text{ton}=10^{3}\,\text{kg}