Which of the following equations represents a reaction for which the enthalpy change of formation of water, ΔH form?
Correct answer: B. H2 (g) + ½ O2 (g) -> H2O (l)
- A. H+ (aq) + OH-(aq) -> H2O(l)
- B. H2 (g) + ½ O2 (g) -> H2O (l)
- C. H2O(g) + H2O(l)
- D. H2O(s) -> H2O(l)
Explanation
The reaction H₂(g) +1/2 O₂(g) → H₂O(l) shows the standard enthalpy change for the formation of water, where △H is the heat of formation of water.
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About Enthalpy
Enthalpy is the heat content of a system measured at constant pressure, and its change indicates whether a reaction or physical process is endothermic or exothermic. The topic covers state functions, enthalpy diagrams, standard enthalpy of formation, combustion and neutralisation, and the relationship between ΔH and internal energy change.
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