Which direction, forwards or reverse, is exothermic for N2 + 3H2 ⇌ 2NH3 ΔH = -92 kJmol-1?

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Multiple Choice

Which direction, forwards or reverse, is exothermic for N2 + 3H2 ⇌ 2NH3 ΔH = -92 kJmol-1?

Explanation:
When a reaction has a negative enthalpy change, it releases heat. Here, the forward direction N2 + 3H2 → 2 NH3 has ΔH = -92 kJ/mol, so it is exothermic—the forward path releases heat. The reverse direction would require energy input (+92 kJ/mol), so it’s endothermic. Therefore, the exothermic direction is the forward one. Choices stating both or neither would conflict with the single enthalpy sign provided for the written direction.

When a reaction has a negative enthalpy change, it releases heat. Here, the forward direction N2 + 3H2 → 2 NH3 has ΔH = -92 kJ/mol, so it is exothermic—the forward path releases heat. The reverse direction would require energy input (+92 kJ/mol), so it’s endothermic. Therefore, the exothermic direction is the forward one. Choices stating both or neither would conflict with the single enthalpy sign provided for the written direction.

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