Atom economy


  • The atom economy (atom utilisation) is a measure of the amount of starting materials that end up as useful products. It is important for sustainable development and for economic reasons to use reactions with high atom economy.

The percentage atom economy of a reaction is calculated using the balanced equation for the reaction as follows:

Students should be able to:

Relative formula mass of desired product from equation × 100Sum of relative formula masses of all reactants from equation

  • calculate the atom economy of a reaction to form a desired product from the balanced equation
  • (HT only) explain why a particular reaction pathway is chosen to produce a specified product given appropriate data such as atom economy (if not calculated), yield, rate, equilibrium position and usefulness of by-products.

WS 4.2 Recognise the importance of scientific quantities and understand how they are determined.

WS 4.6 Use an appropriate number of significant figures in calculation.

MS 1a - Recognise and use expressions in decimal form

MS 1c Use ratios, fractions and percentages

MS 3b Change the subject of an equation