Industrial, Environmental and Applied Chemistry
What this domain tests
Large-scale processes, their conditions and compromises, plus environmental consequences and green-chemistry measures.
Core rules
- Haber process: N2 + 3H2 ⇌ 2NH3, iron catalyst, about 450 °C and 200 atm. High pressure favours ammonia, but temperature is a compromise because the forward reaction is exothermic.
- Contact process: SO2 + ½O2 ⇌ SO3, V2O5 catalyst, about 450 °C and 1–2 atm; SO3 is absorbed in concentrated H2SO4.
- Atom economy = (mass of desired product / total mass of reactants) × 100%; it is not the same as percentage yield.
- Acid rain arises from SO2 and NOx; catalytic converters reduce CO, NOx and unburnt hydrocarbons; CO2 and CH4 are greenhouse gases.
- Addition polymers are hard to depolymerise; condensation polymers can often be hydrolysed.
Worked example
Calculate the atom economy of fermenting glucose: C6H12O6 → 2C2H5OH + 2CO2. Mr glucose = 180; Mr ethanol = 46, so the desired mass is 92. Atom economy = 92/180 × 100 = 51.1%. Almost half the carbon leaves as CO2, which is why yield alone does not capture the efficiency of a route.
Traps
Confusing atom economy with percentage yield; saying a catalyst increases equilibrium yield; attributing acid rain to CO2; forgetting that industrial conditions balance rate, yield, energy cost and safety.