2) Atom economy

•  Atom economy is a measure of the amount of reactant that ends up in a useful product.
• Scientists try to choose reaction pathways that have a high atom economy. This is important for economic reasons and for sustainable development, as more products are made and less waste is produced.
• The higher the yield, the more efficient the process
• atom economy =

  relative formula mass of the desired product sum of the relative formula mass of all the products/reactants

  × 100
• Ethanol can be produced in two different ways: hydration and fermentation. • During hydration, ethene is reacted with steam to form ethano
• The atom economy for the hydration method is 100%.
• • The hydration of ethene is an addition reaction - all the reactant atoms end up in the desired product.
• Ethanol can also be produced by the fermentation of glucose
• The atom economy for this reaction pathway is much lower - only about half of the atoms in the reactants end up in the desired product.