Testing fuel to determine its energy content

Testing fuel to determine its energy content

ZIMSEC O Level Combined Science Notes: Experiment:investigating fuel efficiency

Aim: To determine the amount of heat liberated when different liquid fuels burn

Materials:  2 spirit burners, wooden block, clamp and stand, meths, paraffin, thermometer, draught shields, clamp, beaker, water, tripod stand, measuring cylinder

Method

  1. Pour 100cm3 of water into a beaker
  2. Record the temperature of the water
  3. Fill one spirit burner with meths/methylated spirit
  4. Place the burner under the beaker and heat the water
  5. Stir the water constantly and extinguish the flame when the temperature of the water has increased by 20°C
  6. Note the temperature of the water
  7. Reweigh the burner taking note of how much fuel has been burnt
  8. Repeat this experiment using paraffin as the liquid fuel

Results/Observations and conclusion

  • Less paraffin in terms of weight is required to raise the temperature of the water by 20°C
  • More meths( ethanol) is required to raise the temperature of the water by 20°C
  • However paraffin produced smoke and soot that made it a less ideal fuel to use in meth burners

Conclusion

  • Paraffin has more energy per gram than ethanol
  • Paraffin is difficult to burn completely in air
  • It produces smoke and soot due to incomplete combustion
  • Different fuels have different energy content
  • The table below shows the energy content of various fuels
Solid FuelsWood
Coal
Coke
Charcoal
17
26
28
33
Liquid FuelsEthanol
Petrol
Paraffin
Diesel
30
44
48
55
Gas FuelsBiogas
Coal gas
Butane
Methane
Hydrogen
40
43
50
55
60

To access more topics go to the Combined Science Notes page.