Question 21N.1.sl.TZ0.14

Which combustion reaction releases the least energy per mole of C₃H₈?

Approximate bond enthalpy / kJ mol⁻¹
O=O    500
C=O    800
 C≡O   1000

A.  C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O (g)

B.  C₃H₈(g) + $\frac{9}{2}$O₂(g) → 2CO₂(g) + CO (g) + 4H₂O (g)

C.  C₃H₈(g) + 4O₂(g) → CO₂(g) + 2CO (g) + 4H₂O (g)

D.  C₃H₈(g) + $\frac{7}{2}$O₂(g) → 3CO (g) + 4H₂O (g)

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