Topic 8 Fuels And Earth Science Flashcards
What is a crude oil
A non renewable resource
What are most the compounds in crude oil
Hydrocarbons
What are hydrocarbons
Compounds that contain ONLY carbon and hydrogen
What is fractional distillation
Process of seperating crude oil into groups of hydrocarbons with similar numbers of carbon atoms
What are hydrocarbons with few carbon atoms called
Short chain hydrocarbons
What are the stages of fravtional distillation
. Crude oil enters condensation chamber
. Compound heats up and the hot vapour rises
. Vapour condenses as the compounds go up the chsmber
. Vapour turns into liquid at boilimg point and leaves the chamber at different trays as different compounds have differeny boiling points
In the homologous series what happens when the carbon chains get longer
The boiling point increases
What are the hydrocarbons properties
Flammability - hydrocarbons with longer chains are less flammable
Boiling point - longer chains have higher boiling point
Viscosity - longer chains have higher viscosity
What is cracking
The process that breaks down long chain hydrocarbons into shorter chain molecules that are more usefull.
Example of thermal decomposition reaction
In what 2 ways can cracking be done
Catalytic cracking
Steam cracking
How does catalytic cracking work
Vapourised heavy hydrocarbons are passed over the top of a heated catalyst
Alkanes amd alkenes are produced by this reaction
How does steam cracking work
Vapourised heavy hydrocarbons are mixed with steam in a high temperature environment.
What does the combustion of hydrocarbons depend on
The amount of oxygen that is available
What happens when alkanes are burned without enough oxygen
Carbpn monoxide can be created
What are problems with incomplete combustion
Carbon monoxide
Soot build up
How are nitrogen oxides formed
When hydrocarbons are burned in a small space then the high temperatures can cause nitrogen and oxygen to react
What are advantages of hydogen fuel cells instead of petrol
Only waste product is water so no green house gasses are emitted
Disadvantage of hydrogen fuel cells instead of petrol
Has to be stored at high pressure
Can be explosive
Not many places to refuel
What does acid rain cause
steel corrosion, the weathering of buildings and statues, and the death of insects, plants, and aquatic organisms.
