C1b Flashcards
What are the key factors that need to be considered when choosing a fuel for a particular purpose?
Energy value - amount of energy
Availability - it is easy to get hold of
Storage - is it flammable or explosive?
Cost - good value in terms of energy content?
Toxicity - toxic? Produces poisonous fumes?
Pollution - will be adding to acid rain/ greenhouse effect
Ease of use - light easily? Move it safely?
Why is the amount of fossil fuels being burnt increasing?
Increasing world population.
Growth of use in developing countries like China/ India.
This means more fossil fuels ae burned to provide electricity for home use and manufacturing industries.
What does the combustion of a fuel release?
Useful heat energy.
Why does complete combustion need a plentiful supply of air?
So the elements in the fuel fully react with oxygen.
What does complete combustion of a hydrocarbon fuel only make?
Carbon dioxide and water.
Describe an experiment to show that combustion of a hydrocarbon in a plentiful supply of air produces carbon dioxide and air.
Water pump draws gases from the burning fuel through the apparatus. Water collects inside the cooled u-tube and you can show that it’s water by checking it’s boiling point. The limewater turns milky, showing the carbon dioxide is present.
Why does incomplete combustion take place?
There is a lack of oxygen.
Why does a blue Bunsen flame release more energy than a yellow flame?
The air hole is open, so there is more oxygen and complete combustion takes place, releasing useful energy. With a yellow flame, the air hole is closed, blocking the oxygen.
What does a yellow flame produce lots of?
Soot.
What does incomplete combustion of a hydrocarbon fuel make?
Carbon monoxide, carbon and water.
What is carbon monoxide?
A poisonous gas.
What are the advantages of complete combustion over incomplete combustion of hydrocarbon fuels?
There is more useful heat energy, no messy soot and no poisonous gases.
