Fuels Flashcards
What is energy?
The ability to work
What produces energy in a combustion reaction?
Fuel
What is the unit for energy?
Joules (J)
What is thermochemistry?
The study of heat change in a reaction
What is kinetic energy?
associated with movement (in doing work)
What is potential energy?
Stored energy (ready to work)
What are different types of kinetic energy?
- mechanical
- chemical
- light
- sound
- heat
What are different types of potential energy?
- chemical
- gravitational
- magnetic
- elastic
- nuclear
- electrical
What is the total energy of an object composed of?
The sum of its potential and kinetic energy
What is the first law of thermodynamics?
Energy is neither created nor destroyed but simply changes form one form to another. (Total quantity of energy remains the same)
What is the second law of thermodynamics?
Although the quantity of energy remains the same the quality/ usability gets worse
Why does the energy usability get worse?
Because when energy is converted heat is produced which is low temp and hard to use again
What is the formula for %efficiency?
%efficiency= energy obtained in desired form/ energy available before conversion x100
What are non renewable energy sources?
Used up faster than they can be produced eg. Fossil fuels, nuclear energy
What are renewable energy sources?
Are produced at a faster rate than they are consumed or used eg. Solar etc.
What are the different types of fossil fuels?
Coal, oil, gas
Why is electricity considered a secondary fuel?
Because it is not a natural source of power, it is produced from another fuel/ energy source
How is bioethanol produced?
From the fermentation of sugar
How much bioethanol can be blended with petrol?
10%
What are the advantages of bioethanol?
- reduces pollutants
- reduces greenhouse gases
- oxygen in ethanol assists complete combustion of petrol
What are the disadvantages of bioethanol?
- cost
- less energy
- can contribute to plastic/ rubber breakdown
How is biodiesel produced?
Are alkyl esters produced from vegetable oil or animal fats combined with an alcohol, usually methanol
How much biodiesel can be blended with petrol?
20%
What are the advantages of biodiesel?
- decreased dependence on imported fuels
- biodegradable
- lower pollutants
- no engine modification required
- lubricant properties
What are the disadvantages of biodiesel?
- cost
- high viscosity (unsuitable for cold temps)
- large area required= loss of habitat
How is biogas produced?
From the bacterial breakdown of organic material in the absence of oxygen
Is biogas a combustible fuel?
Yes
What are the advantages of biogas?
- can be produced on a large scale
- can generate electricity, light, heat, motion and fuels such as ethanol
- can be used to fuel vehicles
What types of vehicles is diesel most often used for?
Large vehicles eg. Boats, trucks etc.
How many carbon atoms does petrol diesel contain?
12-24
What does a hygroscopic substance do?
Absorbs water
What’s is a fuel?
A substance used for producing energy by combustion
