Explanation:
Ammonia will decompose into nitrogen gas and hydrogen gas according to the following reaction. In that reaction 92 kJ will be absorbed.
2 NH₃ ----> N₂ + 3 H₂ ΔH = 92 kJ
Since the heat is absorbed, the sign is positive and we can add it to the reactants side.
2 NH₃ + 92 kJ ----> N₂ + 3 H₂
When 92 kJ are absorbed 34 g of ammonia are reacted. We can use that relationship to find the mass of ammonia that reacted when 184 kJ where absorbed.
34 g of NH₃ : 92 kJ
mass of NH₃ = 184 kJ * 34 g of NH₃/(92 kJ)
mass of NH₃ = 68 g
Answer: 68 g of ammonia were decomposed.
2 NH₃ ----> N₂ + 3 H₂ ΔH = 92 kJ
