C3

• over millions of years Britain has moved across the Earths surface
• 600 million years ago, England and Wales were seperated by Scotland
• different continents drifted and crashed together to form a supercontinent, Pangea
• Britain was nearer the equator with a warmer climate
• Different climates existed in Britian from tropical swamps to ice ages 
• as volcanic lava solidifies, igenous rocks are formed
• magnetic materials in the lava line up along the Earths magnetic field
• Geologists can date rocks and track the slow movement of continents using changes in magnetic patterns, linked to radioactive decay
• the evidence supports plate tectonic theory

• over millions of years Britain has moved across the Earths surface
• 600 million years ago, England and Wales were seperated by Scotland
• different continents drifted and crashed together to form a supercontinent, Pangea
• Britain was nearer the equator with a warmer climate
• Different climates existed in Britian from tropical swamps to ice ages 
• as volcanic lava solidifies, igenous rocks are formed
• magnetic materials in the lava line up along the Earths magnetic field
• Geologists can date rocks and track the slow movement of continents using changes in magnetic patterns, linked to radioactive decay
• the evidence supports plate tectonic theory

• Coal contains fossils of the plants that formed it
• Limestone contains bits of shell fragments from sea creatures
• Rock salt contains different shaped water eroded grains and wind eroded grains
• Ripple marks in rocks indicate water flow from rivers or waves in the sea

• used in the food industry, and to treat icy roads in winter
• salt can be obtained from collecting and evaporating sea water, mining, and underground deposits of rock salt
• rock salt is spread on icy roads because rock is insoluble but the sand in the rock gives it grip
• salt extraction from sea water is only economical in hot climates

risks of eating salt

• salt intake can cause high blood pressure

• Alkalis make indicators change colour
• Alkalis neutralise acids to make salts
• acid+alkali--->salt+water
• the first alkali to be manufactured was calcium oxide
• general patterns of reactions: hydroxide+acid--->salt+water
•                                            carbonate+acid--->salt and water and carbon dioxide

The LeBlanc Process

• made sodium carbonate by reacting salt and limestone, heated with cole
• gave off large amounts of hydrogen chloride which is a harmful gas
• produced lots of solid toxic waste
• hydrogen chloride had to be changed into useful substances
• hydrogen chloride was oxidised to make chlorine, a useful product

• chlorine is added to drinking supplies to kill microorganisms
• chlorine is a toxic gas and can affect human health if too much is present in water

• the breaking up of compounds through an electrical current
• the electrolysis of brine makes chlorine gas, hydrogen gas, and sodium hydroxide solution
• the anode is a positive electrode
• the cathode is the negative electrode
• brine forms at the anode and hydrogen at the cathode

• PVC is a plastic containing carbon, hydrogen, and chlorine
• small molecules called plasticiser are added to PVC to make it softer
• plasticiser molecules can leach out PVC into surroundings which may be harmful
• plasticised PVC childrens toys have been banned in the USA and Europe
• if PVC is burned it gives off toxic gases

Life Cycle Assessment

• measures the energy used to make, use, and dispose of a substance and its environmental impact