How much heat is absorbed/released when 20.00 g of NH₃(g) reacts in the presence of excess O₂(g) to produce NO(g) and H₂O(l) according to the following chemical equation?
4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(l) ΔH° = +1168 kJ

Question

Quizplus · Accepted Answer

The reaction is endothermic (ΔH° = +1168 kJ), meaning heat is absorbed. First, calculate moles of NH₃: 20.00 g / 17.03 g/mol = 1.175 moles. The reaction absorbs 1168 kJ for 4 moles of NH₃, so for 1.175 moles, it absorbs (1168 kJ / 4 moles) * 1.175 moles = 342.9 kJ.

How Much Heat Is Absorbed/released When 20