Ammonium sulfate, (NH4)2SO4(\text{NH}_4)_2\text{SO}_4(NH4)2SO4, is a widely used industrial fertilizer. It can be manufactured by two different methods:
Method 1: Direct neutralization of ammonia with sulfuric acid
2NH3+H2SO4→(NH4)2SO4 2\text{NH}_3 + \text{H}_2\text{SO}_4 \rightarrow (\text{NH}_4)_2\text{SO}_4 2NH3+H2SO4→(NH4)2SO4atom economy = 100%
Method 2: Reaction between ammonium carbonate and gypsum (calcium sulfate)
(NH4)2CO3+CaSO4→(NH4)2SO4+CaCO3 (\text{NH}_4)_2\text{CO}_3 + \text{CaSO}_4 \rightarrow (\text{NH}_4)_2\text{SO}_4 + \text{CaCO}_3 (NH4)2CO3+CaSO4→(NH4)2SO4+CaCO3atom economy = 56.9%
State why Method 1 has an atom economy of 100% [1].
157 exam-style questions on Edexcel GCSE Chemistry 6.2 Quantitative analysis, covering 6.2.1 Concentration in mol dm⁻³ and titration calculations, 6.2.2 Percentage yield and why actual yield falls short, 6.2.3 Atom economy of a reaction, 6.2.4 Choosing a reaction pathway, and 6.2.5 Molar volume of gases and Avogadro's law. Each one has a worked solution and a mark scheme showing where the marks go.