Chemistry - Thermochemistry Question with Solution | TestHub
ChemistryThermochemistryEnthalpy of CombustionEasy2 minQB
ChemistryEasysingle choice
Passage / Comprehension
Study the following thermochemical equations:
(a) C2H6(g) → C2H4(g) + H2(g); ΔH = +32.7 kcal
(b) C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l); ΔH = -337.2 kcal
(c) H2(g) + 1/2 O2(g) → H2O(l); ΔH = -68.3 kcal
(d) C(graphite) + O2(g) → CO2(g); ΔH = -94.0 kcal
The enthalpy of combustion (in kcal/mol) of C2H6(g) is
Options:
Answer:
A
Solution:
C2H6 → C2H4 + H2 (+32.7); burn C2H4 (-337.2); burn H2 (-68.3). Sum: 32.7 - 337.2 - 68.3 = -372.8 kcal/mol, for C2H6 + 7/2 O2 → 2CO2 + 3H2O(l). Ans (a).
Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Enthalpy of Combustion
⏱ 2mℹ️ Source: QB
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