Alcohol combustion

• What is the aim of the experiment on alcohol combustion?

  Investigate temperature rise in water
• What equipment is needed for the alcohol combustion experiment?

  • Copper can
  • Clamp stand
  • 100 cm​3 measuring cylinder
  • Thermometer
  • Digital balance
  • Wooden splint and matches
  • Heatproof mat
  • Access to a tap
• What chemicals are required for the experiment?

  • Ethanol
  • Propanol
  • Butanol
  • Pentanol
• What is the first step in the method of the experiment?

  • Place a copper can in a clamp stand
  • Adjust height above flame
• How much water should be poured into the copper can?

  100 cm​3
• What should be recorded after pouring water into the copper can?

  Initial temperature
• What should be measured before lighting the spirit burner?

  Initial mass of the spirit burner
• What should be done after lighting the spirit burner?

  Replace the lid when temperature rises
• What should be done with the water during the experiment?

  Stir the water constantly
• What should be measured after the temperature has risen?

  Final mass of the spirit burner
• What are the possible sources of error in the experiment?

  • Heat loss to surroundings
  • Flame height variations
  • Incomplete combustion
  • Alcohol evaporation during weighing
• Why is a digital temperature probe preferred over a thermometer?

  It measures temperature to two decimal places
• What variables must be controlled for a fair comparison?

  • Mass/volume of water
  • Height of copper can above wick
  • Height of flame
  • Shape of copper container
  • Number of moles of alcohol
• What is the combustion equation for ethanol?

  C​2​H​5​OH + 3O​2​ → 2CO​2​ + 3H​2​O
• What safety precautions should be taken during the experiment?

  • Use a wooden splint to light burner
  • Don’t move the burner when lit
  • Ensure good ventilation
  • Tie back long hair
  • Don’t leave the flame unattended
• How should results from the experiment be recorded?

  • Use a table with columns for:
  • Initial temperature of water
  • Final temperature of water
  • Temperature change
  • Initial mass of spirit burner
  • Final mass of spirit burner
  • Change in mass of spirit burner
• What happens to temperature increase with more carbon atoms in a molecule?

  Greater temperature increase occurs