Chemistry - Thermochemistry Question with Solution | TestHub
ChemistryThermochemistryHess's Law of Constant Heat SummationEasy2 minQB
ChemistryEasysingle choice
The intermediate GeH2 is formed in the thermal decomposition of germanium hydrides. Calculate Δf H° of GeH2 from the following reactions:
Ge2H6(g) + H2(g) → 2GeH4(g); ΔH° = -10.5 kJ/mol
GeH4(g) → GeH2(g) + H2(g); ΔH° = +220.5 kJ/mol
Δf H°, Ge2H6(g) = +75.5 kJ/mol
Options:
Answer:
A
Solution:
From the first reaction: 2Δf H(GeH4) = -10.5 + 75.5 = 65.0, so Δf H(GeH4) = 32.5 kJ/mol. From the second: Δf H(GeH2) = 32.5 + 220.5 = 253 kJ/mol. This is option (a).
Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Hess's Law of Constant Heat Summation
⏱ 2mℹ️ Source: QB
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