Metamorphic
Rocks pushed deep underground where they are compressed and heated. They don’t melt and may change overtime. E.g. Slate to Mudstone and clay and Marble to Limestone.
The Earth
The core is made from Iron and Nickel.
Radioactive decay creates heat inside Earth.
The lithosphere is cracked into Tectonic plates
Plates sliding past each other cause earthquakes e.g. San Andreas Fault.
When Oceanic and continental plates collide, oceanic plate goes under this is called a subduction zone.
Crust pushed down and melts causes a Volcanoes, earthquakes, oceanic trench and mountains.
Sea floor spreading : Mid - Atlantic Ridge
Plates move apart magma fills gap to make new crust made from BASALT.
Crude Oil
- Fossil fuels were formed from dead plants and animals.
- Then were covered by sediments in seas or swamps to stop decay.
-
After millions of years heat and pressure turned it to CRUDE OIL and NATURAL GAS. Used for transport.
-
To split crude oil you use FRACTIONAL DISTILLATION.
-
Bigger and longer molecules, less runny hydrocarbon are.
Hydrocarbons
A hydrocarbon atom has 1 bond.
As the size of the hydrocarbon molecule increases:
- Boiling point increases
- It gets less flammable
- It gets more viscous
- It gets less volatile (doesn’t evaporate easily)
Cracking Hydrocarbons (spliting up long chain molecules)
Cracking is form of thermal decomposition. (Breaking molecules smaller by heating)
Alkanes
THEY ALL HAVE C-C BONDS
- They are saturated- will not decolourise.
Methane Ethane Propane Butane
H H H H H H H H H H
H - C - H H C - C - H H - C- C- C- H H –C –C –C –C -H
H H H H H H H H H H
Alkenes
ALL HAVE C=C BONDS
- They are unsaturated
- Burn with a smoky flame
Ethene Propene Butene
H H H H H H H H
C=C H- C- C =C H - C –C =C –C -H
H H H H H H H
- Bromine water is standard test to distinguish ALKANES and ALKENES
- ALKENES are more reactive due to double bond
Polymers and plastics
Alkenes open their double bond to form polymers
PROCESS OF JOINING ALKKES TO FORM PLASTIC IS CALLED POLYMERISATION.
The individual units which hold together to form polymer is called the MONOMER.
Gases in the atmosphere
78% Nitrogen
21% Oxygen
1% Argon
0.04% Carbon dioxide also varying amounts of water vapour
and noble gases
BURNING FOSSIL FUELS RELEASES C02, WATER AND SULPHUR DIOXIDE
Oceans
Oceans hold a lot of carbon and were formed by condensation of steam in early atmosphere.
Evolution of Earth’s atmosphere
-
Volcanoes gave out stream C02, NH3 and CH4.
- Molten surface boiled away
-
Thin crust formed, volcanoes erupted releasing C02, steam, ammonia and methane
- Atmosphere was mostly C02
-
Water vapour condensed and formed oceans and seas
Green plants removed C02 and made 02
This killed off animals and new ones developed that could tolerate 02
02 also created ozone layer, which filters out harmful rays
Greenhouse effect
C02 in atmosphere is rising due to burning fossil fuels
Earth warms up
C02 adds to greenhouse effect
