OCR Gateway GCSE Chemistry

Revision Notes

5.1.7 Atom Economy

Test Yourself

Atom Economy

  • Along with the percentage yield, atom economy is used to analyse the efficiency of reactions
  • Most reactions produce more than one product and very often some of them are not useful
  • Atom economy studies the amount of reactants that get turned into useful products
  • It illustrates what percentage of the mass of reactants become useful products
  • It is used extensively in the analysis of systems and procedures in industries, in an effort to obtain sustainable development
  • It is also a very important analysis for economic reasons as companies prefer to use processes with higher atom economies
  • The higher the atom economy of a process then the more sustainable that process is
  • The equation for calculating atom economy is:

Worked example

Hydrogen gas is obtained from methane in a process called steam-methane reforming.

The reaction is as follows:

CH4 (g) + H2O (g) → CO (g) + 3H2 (g)

Calculate the atom economy of this reaction.

Answer

Atom Economy WE, downloadable IGCSE & GCSE Chemistry revision notes

Exam Tip

Unwanted by-products can sometimes be put to use, so although a low atom economy is a sign that a process is not green (sustainable) it doesn’t necessarily imply that the process is not economically viable.

The only way to improve the atom economy is to change the chemicals used. It cannot be improved by a more complete reaction or by reducing loss of reactants during the process, as is the case with percentage yield.

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 80,663 Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Jennifer

Author: Jennifer

Jenny graduated in 'Chemistry for Drug Discovery' from the University of Bath in 2006, followed by her PGCE in secondary science, and has been teaching chemistry to 11-18 year olds ever since. She has taught GCSE and A-level chemistry for over 16 years and been a Director of Science for over 6 years, as well as tutoring and writing science books. Jenny loves helping students to understand the core concepts in chemistry and the links between topics, so is now happily working at Save My Exams to support more students to succeed in their learning.