Chemistry - Thermochemistry Question with Solution | TestHub
ChemistryThermochemistryEnthalpy of CombustionMedium2 minQB
ChemistryMediumsingle choice
Passage / Comprehension
Study the following thermochemical equations:
2H2(g) + O2(g) → 2H2O(g); ΔH = -483.636 kJ
3H2(g) + O3(g) → 3H2O(g); ΔH = -868.2 kJ
H2(g) + H2O2(g) → 2H2O(g); ΔH = -347.33 kJ
Which of the reaction will generate the greatest amount of energy on a total mass basis of reactants?
Options:
Answer:
B
Solution:
The total reactant mass for H₂-O₂ is 4 + 32 = 36 g, yielding 483.636/36 = 13.43 kJ/g.
For H₂-O₃, the total reactant mass is 6 + 48 = 54 g, yielding 868.2/54 = 16.08 kJ/g.
For H₂-H₂O₂, the total reactant mass is 2 + 34 = 36 g, yielding 347.33/36 = 9.65 kJ/g.
The greatest value is obtained from H₂-O₃. Therefore, the answer is (b).
Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Enthalpy of Combustion
⏱ 2mℹ️ Source: QB
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