Which of the following have Δ f H ∘ = 0 at 298 K?

Chemistry - Thermochemistry Question with Solution | TestHub

ChemistryThermochemistryEnthalpy of FormationEasy2 minQB

ChemistryEasymultiple choice

Which of the following have $Δ_{f} H^{\circ} = 0$ at 298 K?

Answer:

A, C

Solution:

$Δ_{f} H^{\circ} = 0$ only for an element in its most stable standard state. Bromine is liquid and mercury is liquid at 298 K: (A), (C).

Iodine is a solid at 298 K, so $I_{2} (g)$ is not the reference state. Graphite, not diamond, is the reference state of carbon. Answer: A, C.

Stream:JEESubject:ChemistryTopic:ThermochemistrySubtopic:Enthalpy of Formation

⏱ 2mℹ️ Source: QB

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