Chapter 9: Crude Oils And Fuels Flashcards
What is a crude oil?
A mixture of many different compounds
What compounds makes up most of the mass of crude oil?
Hydrocarbons
What are hydrocarbons made up of?
They only contain hydrogen and carbon atoms
What are alkanes?
They are saturated hydrocarbons, they contain as many hydrogen atoms as possible in their molecules.
What is the general formula for an alkane?
C(s)nH(s)(2n+2)
(S) means small
How is crude oil separated?
Into fractions using fractional distillation
What determines the properties of the fraction of hydrocarbon?
Depends on the size of the hydrocarbon molecules in it.
What are lighter fractions more commonly used as?
Fuels as they ignite more easily and burn well with a less smoky flame.
What happens when hydrocarbon fuels are burnt in plenty of air?
The carbon and hydrogen in the fuel are completely oxidised. They produce carbon dioxide and water.
What happens in incomplete combustion?
Along with carbon dioxide and water carbon monoxide is also produced.
How do you tests the gases formed in complete combustion?
The carbon dioxide of a reaction will turn limewater cloudy.
The water turns blue cobalt chloride paper pink.
How can large hydrocarbon molecules be broken up?
By passing the vapours over a hot catalyst or by mixing them with steam and heating to a very high temperature.
What does cracking hydrocarbons produce?
It produces saturated hydrocarbons, used as fuels, and unsaturated hydrocarbons called alkenes
How do you test for alkenes?
They react with orange bromine water, turning it colourless.
What are the waste products of the complete combustion of hydrocarbons?
Carbon dioxide and water
