How do you equate heat of reaction to heat of formation?

Write the balanced chemical reaction whose #DeltaH _"rxn" = DeltaH_f#

1 Answer
Ernest Z.
Jun 12, 2017

See below.

Explanation:

The heat of reaction #Δ_text(r)H# is the heat involved when a reaction takes place.

If the reaction involves the formation of a compound from its elements in the standard states, the heat of reaction is also called the heat of formation #Δ_text(f)H# of the compound.

As an example, for the reaction

#"2H"_2"(g)" + "O"_2"(g)" → 2"H"_2"O(l)", Δ_text(r)H = "-285.8 kJ· mol"^"-1"#

This reaction involves the formation of a compound from its elements, so the heat involved is also #Δ_text(f)H#.

For a reaction in which a compound is formed from its elements,

#Δ_text(r)H = Δ_text(f)H#

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