Given the Abbreviated Table for Selected Standard Molar Entropy Values

question 31

Multiple Choice

Given the abbreviated table for selected standard molar entropy values of each substance in the reaction below, what is the standard molar change in entropy, D S rxn , for the following reaction?
3 NO₂ (g) + H₂ O ( ) 2 HNO₃( ) + NO (g) Substance S (Jmol - 1 K - 1 ) NO₂ (g) 239.9 H₂ O ( ) 69.94 HNO₃( ) 155.6 NO (g) 210.65

• A) D S ° _rxn = - 267.8 Jmol ^{- 1}K ^{- 1}
• B) D S ° _rxn = - 127.9 Jmol ^{- 1}K ^{- 1}
• C) D S ° _rxn = 56.4 Jmol ^{- 1}K ^{- 1}
• D) D S ° _rxn = 1171.6 Jmol ^{- 1}K ^{- 1}
• E) D S ° _rxn = 1311.5 Jmol ^{- 1}K ^{- 1}

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Definitions:

Periodic Inventory System

An inventory accounting system where the inventory is physically counted at specific intervals to determine the cost of goods sold and ending inventory value.

Average Cost

An inventory costing method where all costs of inventory purchased are averaged to determine the cost of goods sold and ending inventory value.

Unit Cost

The cost incurred to produce, acquire, or deliver one unit of a product or service.