An adhesive manufacturer is choosing between two pathways for making hardener C.
The balanced equation for Pathway 1 is:
A + 2B → C + D
Substance C is the desired product.
| Substance | Relative formula mass, Mr |
|---|---|
| A | 50 |
| B | 25 |
| C | 80 |
Pathway 2 also makes substance C and has an atom economy of 95%.
Calculate the atom economy for making substance C using Pathway 1.
For a theoretical comparison, assume that all the reactants are converted into products and none of substance C is lost. The manufacturer needs to make 760 kg of substance C each day.
Calculate the mass of unwanted by-products produced each day by each pathway.
The waste store has a capacity of 100 kg and is emptied once each day. Waste disposal is charged per kilogram.
Use your answers to justify which pathway the manufacturer should use.
104 exam-style questions on AQA GCSE Chemistry 3.3 Yield and atom economy of chemical reactions, covering 3.3.1a Percentage yield, 3.3.1b Theoretical mass of a product, 3.3.2a Atom economy, and 3.3.2b Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.