C12 Hydrocarbons and Crude Oil Flashcards
What kind of molecules are alkanes?
Saturated hydrocarbons- the carbon-carbon bonds are single
Why are certain hydrocarbons referred to as saturated?
They contain the maximum possible number of hydrogen atoms.
List 3 properties of short-chain hydrocarbons compared to long-chain hydrocarbons:
- Lower viscosity
- Lower boiling point
- Higher flammability
How is crude oil formed?
- Sediment deposits form over plankton remains on seabed
- Over time, sediment builds up to form sedimentary rock
- Animal remains become compressed
- Temperature and pressure increases
- Remains form crude oil
What are the 2 products of complete combustion of hydrocarbons?
Carbon dioxide and water vapour
Which hydrocarbons mainly comprise crude oil?
Alkanes
Why are long-chain alkanes cracked?
As they are in lower demand and more supply than small-chain alkanes
Why is there a higher demand for short-chain hydrocarbons?
They have higher flammability, so make better fuels.
Briefly explain the process of catalytic cracking:
- Long-chain hydrocarbons are vaporised
- The vapour is passed over a hot, powdered catalyst
- The molecules break down
Briefly explain the process of steam cracking:
Vapourised hydrocarbons are mixed with steam and heated.
What molecules are produced in cracking?
Short-chain alkanes and alkenes
List 3 products of cracking and their uses:
- Petrol- car fuel
- Paraffin- jet fuel
- Ethene- plastic production
What does LPG stand for?
Liquefied Petroleum Gases
Define cracking:
A process in which long-chain alkenes are thermally decomposed into smaller molecules
What is crude oil?
A mixture of compounds derived from ancient biomass (i.e. dead plankton)
What can crude oil be used for aside from as fuel?
Can be used as feedstock in the production of solvents, lubricants and detergents
Name a catalyst used in cracking:
Aluminium oxide
