Materials from the Earth

Materials from the Earth

1. C1.5 Rocks & Their Formation

   • igneous rocks
     • solidification of magma/lava
     • interlocking crystals
     • slower cooling = larger crystals
     • e.g. granite
   • sedimentary rocks
     • layers of sediment compacted
     • erode easily
     • may contain fossils
     • e.g. chalk & limestone
   • metamorphic rocks
     • from existing rocks by heat/pressure
     • e.g. marble from chalk/limestone

2. C1.6 Limestone & Its Uses

   • uses
     • concrete/cement/glass
     • construction
     • steel/iron alloys
   • quarrying
     • advantages
       • provides jobs
       • limestone=important raw material
       • exported-aids UK economy
       • jobs help local economies
     • disadvantages
       • spoils scenery
       • lorries produce noise/pollution/traffic
       • dust/noise
       • destroys habitats
   • thermal decomposition
     • CaCO3 --> CaO + CO2

3. C1.8 Chemical Reactions

   • thermal decomposition
     • copper carbonate = easiest
     • zinc carbonate
     • calcium carbonate = hardest
   • atoms
     • smallest particle of element
     • take part in reactions
     • not created/destroyed
     • rearranged
   • mass
     • remains the same in sealed container
   • precipitation reaction
     • 2 soluble reactants form insoluble precipitate

4. C1.9 Reactions of Calcium Compounds

   • making limewater
     • 1. CaCO3 --> CaO+CO2
     • 2. CaO+H2O --> Ca(OH)2
       • fizzing,steam,heat
     • 3. Ca(OH)2+CO2 --> CaCO3+H2O
     • when CO2 is bubbled through calcium hydroxide limewater is produced
   • neutralising acids
     • calcium compounds neutralise acids
       • e.g. in soil
       • e.g. in power stations to get rid of sulphur dioxide and nitrogen oxides
       • this reduces acid rain