Atom Economy and Percentage Yield
- Created by: India.02
- Created on: 28-04-19 19:37
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- Atom Economy and Percentage Yield
- Atom Economy
- % of reactants forming useful products
- 100% atom economy means that all atoms in the reactants have been turned into desired product - the higher the atom economy, the 'greener' the process
- High and Low Atom Economy
- Low atom economy means resources are used up very quickly and they make lots of waste materials that have to be disposed of - reactions tend to be unsustainable if the raw materials are non-renewable
- Reactions may not be profitable because raw materials are expensive and waste can be expensive to dispose of responsibly
- Find a use for the waste rather than throwing it away - come up with a reaction that gives useful by-products
- Reactions with the highest atom economy usually only have one product - these have an atom economy of 100%
- The more products there are, the lower the atom economy is likely to be
- Low atom economy means resources are used up very quickly and they make lots of waste materials that have to be disposed of - reactions tend to be unsustainable if the raw materials are non-renewable
- Percentage Yield
- Compares actual yield and theoretical yield
- Always between 0% and 100% - 0% yield means that no reactants were converted into product - 100% yield means you got all the product you expected to get
- Industrial processes should have high percentage yield to reduce waste and costs
- Yields will always be less than 100% because some reactant or product is always lost
- Three common problems
- Not all reactants react to make a product - in a reversible reaction the products can turn back into reactants - yield will never be 100%
- There might be side reactions - reactants may react differently to how you expect - they might react with gases in air or impurities in the mixture
- You lose product when you separate it from the reaction mixture - when you filter a liquid to remove solid particles you nearly always lose some liquid or solid
- Atom Economy
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