Topic 5 - Fuels
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What are fuels?
Chemicals which give out energy when they burn
What is the test for oxygen gas?
It relights a glowing splint
What, roughly, is the percentage of oxygen and nitrogen in the air?
Oxygen - 20%
Nitrogen - 80%
Reactions that give out heat are said to be _______ reactions?
What are the three main fossil fuels?
Coal, oil and natural gas
How are fossil fuels formed?
They are formed from dead plant and animal remains over millions of years under heat and pressure
What consists of a mixture of compounds which are mostly hydrocarbons?
What process is used to seperate crude oil into fractions?
The higher the viscosity the _______ the liquid is?
As the size of the molecules in the fractions increases the boiling point of the fraction ________ too?
What fractions are the most flammable?
The low boiling point fractions
What are hydrocarbons?
Molecules that contain hydrogen and carbon
What is the test for carbon dioxide?
It turns lime water from clear to milky/chalky
What do hydrocarbons produce when they are burned?
Carbon dioxide and water
If a hydrocarbon burns in a limited supply of oxygen it may produce....?
What does burning fuels with the element sulphur produce?
What does sparking air in a car engine produce?
Oxides of nitrogen
What do oxides of nitrogen dissolve in rain to form?
Nitric acid (acid rain)
How can we decrease air pollution?
By altering the fuel to air ratio
By using catalytic convertors which convert pollutant gases into harmless ones
What metals are used in catalytic convertors?
Platinum, rhodium and palladium
Topic 5 - Fuels
Standard Grade Chemistry - Topic 5 - Fuels