Pentaborane B₅H₉(s) Burns Vigorously in O₂ to Give B₂O₃(s) and H₂O(l)

question 138

Multiple Choice

Pentaborane B₅H₉(s) burns vigorously in O₂ to give B₂O₃(s) and H₂O(l) . What is ΔH° for the combustion of 1 mol of B₅H₉(s) ? Substance ΔH°_f (kJ/mol)
B₂O₃(s) -1273.5
B₅H₉(s) +73.2
H₂O(l) -285.8

• A) -1.5 × 10³ kJ
• B) -1.6× 10³ kJ
• C) -4.4 × 10³ kJ
• D) -4.7× 10³ kJ
• E) -9.0× 10³ kJ

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Definitions:

Absorption Costing

A cost accounting method that includes all manufacturing costs - direct materials, direct labor, and both variable and fixed manufacturing overhead - in the cost of a product.

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Common Fixed Costs

Expenses shared by multiple segments or products within a company that do not change with the level of production or sales.