We are asked to calculate ΔS˚_{rxn} for the balanced chemical equation 2 H_{2}S(g) + 3 O_{2}(g) → 2 H_{2}O(g) + 2 SO_{2}(g)

Calculate ΔS˚_{rxn} using the equation below:

$\overline{){\mathbf{\Delta S}}{{\mathbf{\u02da}}}_{{\mathbf{rxn}}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{\mathbf{S}}{{\mathbf{\u02da}}}_{{\mathbf{products}}}{\mathbf{}}{\mathbf{-}}{\mathbf{}}{\mathbf{S}}{{\mathbf{\u02da}}}_{{\mathbf{reactants}}}}$

Values needed:

S˚ of H_{2}S(g) = 205.8 J/(mol•K)

S˚ of O_{2}(g) = 205.2 J/(mol•K)

S˚ of H_{2}O(g) = 188.8 J/(mol•K)

S˚ of SO_{2}(g) = 248.2 J/(mol•K)

Calculate ΔS˚_{rxn} for the balanced chemical equation

2 H_{2}S(g) + 3 O_{2}(g) → 2 H_{2}O(g) + 2 SO_{2}(g)

**Standard enthalpies for selected substances at 25 ^{o}C **

Substance | ΔS˚ (J/(mol•K)) |

O_{2}(g) | 205.2 |

SO_{2}(g) | 248.2 |

SO_{3}(g) | 256.8 |

H_{2}O(g) | 188.8 |

H_{2}S(g) | 205.8 |

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