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)
