Fuels Flashcards
What is a hydrocarbon?
A compound made up of hydrogen and carbon only
What is crude oil?
A mixture of hydrocarbons made up of molecules where carbon atoms are in chains or rings. It is a finite resource.
What are the 6 different fractions of crude oil?
- Gasses
- Petrol
- Kerosine
- Diesel oil
- Fuel oil
- Bitumen
What are gasses from crude oil used for?
Domestic heating and cooking
What is petrol used for?
To fuel cars
What is kerosine used for?
To fuel planes
What is diesel oil used for?
To fuel trains and some cars
What is fuel oil used for?
To fuel large ships and some power stations
What is bitumen used for?
To surface roads and roofs
Describe the fractional distillation of crude oil
- Crude oil is heated until it vaporises
- It travels up a fractionating column which is hotter at the bottom and colder at the top
- Each fraction of crude oil has a different boiling point and will condense at the right temperature
- Each fraction will then be separately drawn away from the column
Do lighter hydrocarbons have higher or lower melting and boiling points?
Lower melting and boiling points
Are the lighter or heavier hydrocarbons more flammable?
Lighter
What are the products of the complete combustion of a hydrocarbon?
Carbon dioxide and water
What are the products of the incomplete combustion of a hydrocarbon?
Carbon monoxide, carbon and water
What are the dangers of carbon monoxide?
- It is toxic
- It can cause carbon monoxide poisoning
What is the carbon produced in the incomplete combustion of a hydrocarbon in the form of?
Soot
What are the dangers of appliances that use carbon compounds as fuels?
- Could cause incomplete combustion
- Soot can block boilers or cause fires
- Carbon monoxide is toxic
How are oxides of nitrogen produced?
When fuels are burnt in engines the high temperatures cause the oxygen and nitrogen in the air to react
What is cracking?
The breaking down of larger, saturated hydrocarbon molecules into smaller, more useful ones, some of which are unsaturated
What are the reactants of cracking?
Alkanes
What are the products of cracking?
Alkanes and alkenes
What are the reasons for cracking?
- Helps to match the supply of fractions of crude oil with the demand
- It produces alkenes, which are used for feedstock
What are the advantages of using hydrogen to fuel cars over petrol?
- Renewable source of fuel
- Does not produce toxic gas
- Does not produce greenhouse gasses
What are the disadvantages of using hydrogen to fuel cars over petrol?
There are less hydrogen filling stations than petrol
Compare chemical cells and fuel cells
Chemical cells produce voltage until one of the reactants is used up, fuel cells produce voltage continuously as long as there is a fuel (eg. hydrogen) and oxygen
