1. C1b Topic 7 Internal Assessment: Fuels

2. What makes a good fuel?
Energy value: e.g. kJ of heat energy released per kg;
Availability: Geographical convenience, oil production levels;
Storage: Health and safety issues e.g. coal very safe, natural gas more dangerous
Cost: Extraction, transport, market price
Toxicity and Pollution: Greenhouse effect (which produces the least or most CO2/energy released?); sulphur content of fuel (most removed before fuel used to minimise sulphur dioxide and acid rain formation); efficiency of combustion e.g. minimum carbon monoxide and soot levels
Ease of use: Transferred easily

3. Combustion Combustion can be either complete or incomplete
Complete combustion = plenty of oxygen available; carbon dioxide and water produced; blue flame
Incomplete combustion = not much oxygen present; carbon monoxide (toxic), carbon (black soot), carbon dioxide and water produced; yellow flame

4. Word Equations – when done, convert to balanced symbol equations
Methane + oxygen →
Methane = CH4
Ethane + oxygen →
Ethane = C2H6
Ethanol + oxygen →
Ethanol = C2H5OH
Butanol + limited oxygen →
Butanol = C4H9OH

5. Alternative Fuels Most of our fuel used today comes from crude oil
Examples: petrol, diesel, kerosine etc.
Are these fuels renewable or non-renewable?
What is meant by these terms?
What are some alternative fuels that could be used?

6. Some Alternative Fuels
Biodiesel and Bioethanol: liquid fuels made from
plant material and recycled elements of the food chain. To
a large extent, they are renewable and sustainable.
Biodiesel is a diesel alternative. Bioethanol is a petrol
additive/substitute. They are produced from crops such as
cereals, oilseeds, and sugar beet.
What advantages/disadvantages do biofuels have over oil?

7. Hydrogen: can be obtained by the
electrolysis of water (so a bountiful supply!).
Also, when hydrogen burns a lot of energy is
released and is completely pollution-free
(the only product is water).
Hydrogen powered buses produce no pollution from their exhausts, but using hydrogen is not a completely pollution-free option at the moment. Explain why.

8. How Science Works
Reliable – data can be reproduced by others (in same conditions)
Accurate – precise or correct in all details
Valid – data is reliable AND answers the original questions
Fair Testing – controlling as many variables as possible
Bias – opinion that strongly favours one side in preference to another

9. Think about why things might be biased
People who want to make a point can sometimes present data in a biased way to suit their own purposes
Example: companies may want to ‘big up’ their products (especially more expensive ones) to make a quick profit

10. Example: Do power lines cause cancer?
Scientists desire to study the link between the presence of power lines and incidence of cancer in children
Design a study that the scientists could perform. Use ideas of validity, fair testing, accuracy, and reliability when designing your study.