Question

In the important industrial process for producing ammonia (the Haber Process), the overall reaction is: N2(g) + 3H2(g) → 2NH3(g) + 100.4 kJ A yield of NH3 of approximately 98% can be obtained at 200°C and 1,000 atmospheres of pressure. What is the ΔH in kJ of heat released per mole of NH3(g) formed?

A) 50.2 kJ
B) -50.2 kJ
C) 100.4 kJ
D) -100.4 kJ

Answer 1

Answer is: B) -50.2 kJ.

Balanced chemical reaction: N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -100.4 kJ.
This is exothermic reaction, because heat is released and energy is include as product of chemical reaction.
Make proportion, two moles of ammonia released 100.4 kJ of heat, then one mole of ammonia released:
2 mol(NH₃) : (-100.4 kJ) = 1 mol : ΔH.
ΔH = -50.2 kJ; heat released per mole of NH₃.