Choosing a Reaction Pathway (AQA GCSE Chemistry)

Choosing a reaction pathway

Higher tier only

• Reactions that have low atom economies use up a lot of resources and produce a lot of waste material which then needs to be disposed of, a very expensive procedure

• These reactions are thus unsustainable as they use up too much raw material to manufacture only a small amount of product

• They are not economically attractive as raw materials tend to be expensive, as does waste disposal which requires chemicals, equipment, space and transport

• Companies continually analyse reactions and processes and evaluate several factors in an effort to improve efficiency

• Atom economy, percentage yield, rates of reaction and equilibrium position are important factors which need to be considered when choosing a reaction pathway

• High percentage yields and fast reaction rates are desirable attributes in industrial chemical processes

• In reversible reactions, the position of the equilibrium may need to be changed in favour of the products by altering reaction conditions

• If the waste products can be sold or reused in some way that would improve the atom economy

• Alternative methods of production could also be considered that may produce a more useful by-product