Alcohols and carboxylate acids

• What functional group do alcohols contain?

  –OH functional group
• How is ethanol produced from sugars?

  By fermentation
• What functional group do carboxylic acids contain?

  –COOH functional group
• What are the steps to investigate the combustion of alcohols?

  1. Secure a can over a spirit burner.
  2. Measure mass of the spirit burner.
  3. Add 100 cm³ of cold water.
  4. Measure and record water temperature.
  5. Light the wick and stir the water.
  6. Record maximum temperature and mass change.
  7. Repeat with different alcohols.
• What is the aim of the combustion investigation?

  To investigate temperature rise in water
• What should be recorded during the combustion experiment?

  Mass, temperature, and volume
• What is the change in temperature for methanol in the experiment?

  21°C
• How is the change in mass calculated in the experiment?

  Mass at start minus mass at end
• What is the change in mass for methanol in the experiment?

  0.59 g
• How do you calculate the change in temperature per gram of fuel burned?

  Change in temperature divided by mass burned
• What is the change in temperature per gram of methanol burned?

  $35.6°C/g$
• What are the major sources of error in the combustion experiment?

  • Heat loss from water and can
  • Inaccurate measurements
  • Variability in alcohol purity
• Why should the height of the can above the wick be consistent?

  It affects energy transfer to water
• What are the hazards associated with alcohols in the experiment?

  • Highly flammable liquids
  • Toxic contact with skin
  • Risk of burns and fire
• What precaution should be taken when lighting the wick?

  Use a lighted splint
• What should not be done while the spirit burner is alight?

  Do not move the spirit burner
• What is a precaution to take regarding methanol?

  Avoid skin contact
• What are the precautions needed to reduce risks in the experiment?

  • Use appropriate apparatus
  • Handle substances carefully
  • Ensure good ventilation