Atom economy

• What is meant by the atom economy of a reaction?


  It shows how efficiently a reaction uses the atoms in the reactants.
• How is atom economy calculated?

  Atom economy = (relative formula mass of useful product / sum of relative formula masses of all reactants) × 100%
• Why is atom economy important in manufacturing a product?


  It helps to determine the efficiency and waste produced in a reaction.
• What is the atom economy for making ethanol from ethene?


  100%
• What is the balanced equation for the reaction of ethene with steam to produce ethanol?


  C₂H₄ + H₂O → C₂H₅OH
• What is the atom economy for making water from the reaction of hydrogen and oxygen?


  Atom economy = (mass of water produced / mass of reactants) × 100%
• What is the atom economy for making ethanol through fermentation of glucose?


  51.1%
• How do you calculate the atom economy for making urea from ammonia?


  Use the formula: atom economy = (relative formula mass of urea / sum of relative formula masses of reactants) × 100%
• Why is it important to consider atom economy when choosing a reaction pathway?


  It helps to minimize waste and improve sustainability in manufacturing.
• What factors must chemists consider when deciding on a reaction pathway?


  • Energy consumption
  • Rate of reaction
  • Raw materials
  • Conditions for high yield
• Compare the two methods of making ethanol in terms of materials and atom economy.

  • Ethene with steam:
  • Raw materials: Ethene (non-renewable)
  • Atom economy: 100%
  • Fermentation:
  • Raw materials: Carbohydrates (renewable)
  • Atom economy: 51.1%
• What is the atom economy for producing ethanoic acid from ethanol in the reaction CH₃CH₂OH + [O] → CH₃COOH + H₂O?


  Calculate using the formula: atom economy = (mass of ethanoic acid produced / mass of reactants) × 100%
• Why is it better for a reaction to have a high atom economy?


  It reduces waste products and improves resource efficiency.
• Explain how high yield implies low quantities of waste.


  A high yield means more of the reactants are converted into useful products, reducing waste.
• What is the relative formula mass of urea and water?


  Urea = 60; Water = 18
• How do you calculate the atom economy for making urea from the reaction 2NH₃ + CO₂ → CO(NH₂)₂ + H₂O?


  Atom economy = (60 / (2*14 + 12 + 18)) × 100%
• What is the significance of finding uses for by-products in a reaction?


  It can improve the atom economy and reduce waste disposal issues.
• What is the temperature used in the fermentation process for making ethanol?


  30-40°C
• What is the pressure used in the reaction of ethene with steam?


  High pressure (60-70 atm)
• What catalyst is used in the fermentation of sugars?


  Enzymes in yeast
• What catalyst is used in the reaction of ethene with steam?


  Concentrated phosphoric acid
• Why is the purity of the product important in chemical reactions?


  Higher purity means fewer impurities that could affect the product's effectiveness.
• How does the atom economy relate to the environmental impact of a reaction?


  A higher atom economy typically results in less waste and lower environmental impact.
• What is the role of data in deciding the best way to manufacture a product?

  Data helps evaluate efficiency, cost, and environmental impact of different manufacturing methods.