Fuels Flashcards
What is a fuel?
Fuels are chemicals which give out energy when they burn.
What gets used up in the air when fuels combust?
The combustion of fuels uses up oxygen from the air.
What is a reaction that gives off heat?
Reactions that give out heat are called exothermic reactions.
Fossil fuels?
Fossil fuels are a finite resource and cannot be replaced.
What are the three main fossil fuels?
Our three main fossil fuels are coal, oil and natural gas.
How are different substances in a mixture separated?
Because different substances in a mixture have different boiling points they can be separated by fractional distillation into groups of molecules with a certain boiling range.
What does flammable mean?
The warning label “flammable” appears as on many (organic) chemical bottles, to warn of the risk if taken near a flame.
What does viscosity mean?
The larger the molecule the higher the viscosity is of a liquid, i.e the thicker it is.
What does a larger molecule of a hydrocarbon mean?
The larger the hydrocarbon molecules the more energy will be required to evaporate the substance. Hydrocarbons with larger molecules are less flammable.
What is a hydrocarbon?
Hydrocarbons are compounds that contain only carbon and hydrogen atoms.
What is the test for carbon dioxide?
The test for carbon dioxide is that it turns lime water milky/cloudy.
What is the test for water?
The test for water is that it turns cobalt chloride paper from blue to pink.
What happens when hydrocarbons burn?
When hydrocarbons burn they produce only carbon dioxide and water.
What if a hydrocarbon has its air supply restricted while burning.
If a hydrocarbon has its air supply restricted, while it is burning it may produce C (soot) and CO (a poisonous gas) as well as CO2 and H2O.
Why are longer chains of molecules harder to break down?
Longer chains of molecules are harder to break down because the intermolecular forces increase as chain length increases, also longer chains become tangled so need to be boiled at a higher temperature to be broken down.
If a substance has a higher boiling point why would it be less flammable?
If a substance has has a higher boiling point then they are harder to evaporate then there will be less vapours and therefore less flammable.
What is a biofuel?
A biofuel is a fuel made from living matter, bio fuels are also renewable.
What is a catalytic converter?
A catalytic converter is a device found in a car exhaust which can be used to change (convert) harmful pollutant gases into less harmful ones using a catalyst.
Carbon monoxide?
Carbon monoxide’s main source is from incomplete combustion, it is a poisonous gas and it can be prevented by having an adequate supply of oxygen.
Sulfur dioxide?
Sulfur dioxide’s main source is from the burning of fossil fuels, it contributes to the problem of acid rain and it can be prevented by a process called ‘scrubbing’
Unburnt petrol?
Unburnt petrol’s main source is from a car engine, it is toxic and it can be prevented by having an adequate supply of oxygen.
Nitrogen oxides?
Nitrogen oxide’s main source is from a car engine, it can cause acid rain and breathing problems and it can be prevented by a catalytic converter.
