Respuesta :
Answer:
O₂ (g).
Explanation:
- All elements that found in nature has heat of formation (Hf) equal 0 J/mol.
- So, the substance that has heat of formation (Hf) equal 0 J/mol is O₂ (g).
- H₂O is formed from the reaction of hydrogen and oxygen and has Hf, Also, the solidification of H₂O (s) from H₂O (l) has (Hf).
- Although, Ne (g) is found in nature and has no Hf, the liquification to form Ne (l) has heat of formation (Hf).
- CO₂ (g) is formed from the reaction between carbon and oxygen and so has heat of formation (Hf).