ENERGY OF FUELS

Portfolio Activity! This counts toward your final grade!


What are my objectives while studying this topic?


By carrying out an investigation to determine the calorific value of a fuel you’ll be able to determine how much heat energy is released when a fuel is burned.


Why is this important?


We know that all fuels are different: we burn coal compared to gas we get a different amount of heat. Through investigation we can determine which fuel best suits the demands we place on it. For example, burning coal will give us more heat as compared to burning paper.


Can I get an introduction to this topic?



Fuels and their molecules


Methane gas

methane

Chemical compound with the molecular formula CH4. It is the simplest alkane and the principal component of natural gas.

Propane gas

Propane Gas

A three-carbon alkane, normally a gas, but compressible to a liquid that is transportable in canisters and tanks. It is commonly used as a home heating, engine and barbeque fuel.

Butane gas

Butane Gas

An un-branched alkane with four carbon atoms, commonly used as a fuel for cooking and camping.

Methanol liquid

Methanol Liquid

A chemical compound with the formula CH3OH. It is the simplest alcohol and is a light, volatile, colourless, flammable and poisonous liquid, used mostly as an antifreeze, solvent and fuel.

Ethanol liquid

Ethanol

A flammable, colourless alcohol with the formula C2H5OH. It is best known as the alcohol found in alcoholic drinks, but is also used as a fuel for engines, and as the solvent for scents, flavourings, colourings and medicines.

Propanol liquid

Propanol Liquid

A primary alcohol with the formula CH3CH2CH2OH which is mostly used as a solvent in the pharmaceutical industry.

Paraffin liquid

Paraffin liquid

Long chain alkane molecules with the general formula, CnH2n+2 Liquid paraffins typically have values of n ≈ 10+.

Paraffin wax

Paraffin Wax

Long chain alkane molecules with the general formula, CnH2n+2 Solid paraffins typically have values of n ≈ 15+.

Hexamine tablets

Hexamine tablets

A heterocyclic organic compound with the molecular formula C6H12N4 mainly used as a solid fuel tablet for cooking whilst camping.


Activity

 

Now ask yourself the following questions:


  • How will you make your investigation safe?

  • Are there any special regulations that you need to follow?

  • How will make sure your results will be accurate?


Experiment!


Burn a fuel under controlled conditions and devise a way of measuring how much heat energy is released. To do this use a commonly available carbon-based (fossil) fuel in a suitable (safe and approved) burner to heat water, and hence make a measurement of the calorific value of the fuel.


Activity


Now ask yourself the following questions:


  • How will you account for any discrepancies when you compare your values to the researched values carried out by other people?

  • How efficient is your method?


Any references for this?


A suitable standard procedure can be found or adapted from ILPAC Advanced Practical Chemistry, 2nd edition, Revised by Lainchbury, A, Stephens, J and Thompson, A; John Murray, 1997, ISBN 0719575079 Experiment 2.4 Determining enthalpies of combustion.


Note:


There is no requirement that you should use either the standard procedure from ILPAC Exp 2.4, OR, use more complex apparatus such as bomb calorimeters. You can gain full marks by using very simple (but highly inefficient) methods such as heating water in a beaker on a tripod using a spirit burner! A suitable example can be found at:



Activity


You’ll need to write this experiment up for submission. You could use the following writing frame to do this:



Activity


Part of your assessment requires you to use other people’s work such as adapting standard procedures or finding out and using information on the Internet. When you use information like this you need to reference it properly in your reports.



Activity


Portfolio Follow-up


Portfolio work will be marked in accordance to the appropriate assessment criteria:


What other things contribute to my portfolio in this topic?


It is expected that you will be required to complete sections of work on this piece of coursework. Examples might be:


  • Research on bond energies

  • Risk Assessment

  • Tabulation of Results

  • Calculations

  • Interpretation & Conclusions

  • Completion of report


What are the key words to learn and use?


  • Combustion

  • Bonds

  • Enthalpy

  • Standard

  • Dissociation

  • Exothermic

  • Endothermic

  • Specific heat capacity

  • Specific latent heat

  • Vaporisation

  • Fusion

  • Thermal energy

  • Calorimeter


What will I be expected to be able to do after studying this topic?


  • Calculate the calorific value of a carbon-based (fossil) fuel

  • Carry out a practical procedure to measure the calorific value of a carbon-based (fossil) fuel and produce a risk assessment for the procedure

  • Use a suitable standard procedure

  • escribe any regulations governing specific elements of your practical procedure

  • Analyse and monitor the data obtained from this practical procedure

  • Compare your experimental results for the calorific value to standard values

  • Use your data to calculate the efficiency of your procedure


How long will this topic take to study?


On average you’ll be looking at about eight hours. This includes taught time and independent study.


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