1.1.1 contained large amounts of: carbon dioxide & water vapour
184.108.40.206 Hardly any oxygen and small amounts of other gasses
1.2 the earth was very hot to start with.
1.2.1 no oceans
220.127.116.11 as the earth cooled the water vapour condenced to form liquid water
2 The Atmosphere now
3 Rocks and Their Formation
3.1 Igneous Rocks
3.1.1 Are formed when magma or lava solidifies.
3.1.2 made of interlocking crystals
3.1.3 have small crystals if the liquid rock cooled quickly
3.1.4 have large crystals when rock cools slowly
3.2 Sedimentary Rocks
3.2.1 layers of sediment are compacted together over a long time being buried under more
3.2.2 it errodes earier than igenous or metaphorphic
3.2.3 made from rounded grains, may contain fossils
3.2.4 include chalk and limestone- natural forms of callcuim
3.3 Metamorphic Rocks
3.3.1 formed from existing rocks by heat or pressure
18.104.22.168 buried or from nearby magma
22.214.171.124 causing new interlocking crystals to grow
3.3.2 Marble (metamorphic rock) is formed from chalk or limestone
3.4 Limestone and its uses
3.4.2 base for roads or railwaus
3.4.3 mostly made form calcuim carbonate (CaCo3)
126.96.36.199 raw material used to make Glass, cement and concreate
188.8.131.52.1 Limestone is heated when making cement and glass
184.108.40.206.1.1 the heat decomposes the calcium carbonate in it to form calcium oxide (CaO) and carbon dioxide (CO2).
220.127.116.11.1.1.1 in a process called THERMAL DECOMPOSITION Calcuim carbonate - calcium oxide + carbon dioxide
18.104.22.168.22.214.171.124 Thermal Decomosition
126.96.36.199.188.8.131.52.1 Metal Carbonates decompose when heated to form an oxide and carbon oxide.
184.108.40.206.220.127.116.11.2 some decompose more easily than others
4 Reactions of calcium carbonates
4.1 The Limestone Circle
4.2 Lime water
4.2.1 fully diddolved Calcium hydroxide in water
4.2.2 used to test for CO2. Turns milky.
18.104.22.168 CO2 + Ca(OH)2 = CaCo3 (s) + H2O. The solid is suspended in the water
4.3 calcium carbonate is also known as lime stone CaCo3
4.4 calcium carbonate, oxide and hydroxide can
all be used to nutralise acidic compounds.
4.4.1 some soils are acidic. Farmers use it on
their fields to help the crops grow
5.1 our stomachs produce Hydrochloric
5.1.1 Kill bacteria in our food
5.1.2 help digestion
5.2 somethimes too much is produced. causing pain called
5.3 testing remideis
5.3.1 neutral liquids have a pH of 7. Acids less than
5.3.2 when an indigestion remedy is added to an acid. some of the acid is neutralise. pH
to make the investigation a fair test, you must use the same volume of acid each time at the same consentration, and use one dose of each remedy. the remedy that produces the highest pH t the end has neutralised the most acid.
6.1 in indigestion
6.1.1 the remedies contain anti acids that nutralise the excess acid.
22.214.171.124 anti acids contain bases, they react with the acids and nutralise them
126.96.36.199.1 some bases are soluble. a bases disoved in water is called an Alkali
6.1.2 acid+ base - salt + water
6.2 three differnt types of compounds used to nutralise acids
6.2.1 metal oxides (such as copper oxide, CuO )
188.8.131.52 acid + metal oxide - salt + water
6.2.2 metal hydroxides (such as sodium hydroxide, NaOH )
184.108.40.206 Acid + metal hydroxide - salt + water
6.2.3 metal carbonates (such as copper catbonate, CuCo3)
220.127.116.11 acid + metal carbonate - salt + water + carbon dioxide
6.3 Naming Salts
6.3.1 salt is made from a metal and non-metal
6.3.2 hydrochloric acid produces chloride
6.3.3 nitric acid produces nitrate
6.3.4 slufuric acid produces sulfate
7.1 the dangers
chlorine is a toxic gas. this makes it useful as a disinfectant because it kills microorganisms. this also makes chlorine hazardous. chlorine is very useful in industry, and millions of tonnes of it are produced every year.
7.1.1 ohlorine gas is toxic
Sea water contains a lot of dissolved sodium chloride. chlorine gas can be obtained from sea water by electrolysis. chlorine is used to make bleach, and to make plastics such as polychloroethene (PVC)
8.1 of water
8.1.1 produces hydrogen and oxygen gasses
8.2 only works on a D.C
9 Testing for Gasses
9.1.1 hold a glowing alighted splint int the mouth of the test tube if the gas is hydrogen, it will explode with a squeaky pop
9.2.1 hold a glowing splint into the mouth of the test tube. if the gas is oxygen it will relight.
9.3.1 hold a peice of damp blue litmus paper in the test tube. if the gas is chlorine it will bleach the paper white
10.1 some metals are found as elements in the earths crust. the metal is not combined with other elements. these metals are very unreactive.
10.2 extracting metals
10.2.1 most metals are found as part of a
compound in rocks. if the rock has enough
metal compound to extract the rock is
called an ore
10.3 metals such as iron are exctracted their compounds by heating them with carbon.
More reactive metals such as aluminium are extracted by melting the ore then
carrying out electrolysis
11 Oxidation and reduction.
11.1 most metal oxides react with oxygen this causes
corrosion. eg i ron + oxygen = iron oxide. the iron has
been oxidised because it has gained oxygen.
11.2 many metal ores contain oxides. the metal is extracted by
removing the oxygen. aluminium oxide - aluminium +
oxygen. The aluminium oxide has been reduced, the
oxygen has been removed
12 recycling metals
12.1 when a metal object has reached the end of its
life the metal can be melted down and made into
something new. recycling has many beifits.
12.2 recycling menas the earths supply of metals will last longer
12.3 if recycled, we need fewer mines. this helps
the enviroment- mining causes duast and
noise pollution and damages the landscape.
12.4 less land is needed for land fill
12.5 CO2 is emitted when fossil fuels are used to heat ores or
generate electricity used in electrolysis. Far less CO2 is
emitted from the recycling process as less energy is
12.6 for most metals it takes less energy to melt down
used metals than it does to extract from the ore.
recycling is sustainable and cheaper
13 Uses of metals
13.1 metals conduct heat,and electristy.they are malleable and ductile. not all metals
have exactly the same properties. the uses depend on the properties.
13.2.1 used for jewellery because it looks attractive
13.2.2 some electrical connections inside electronic devived
because it is one f the best conductors.
13.3.1 used for electrical cab;es because it is a very good conductor
13.3.2 water pies- it doesnt corrode easily
13.4.1 used for structures because it is strong and resistant to corrosion
13.5.1 used for drinks cans- does not corrode
13.5.2 aeroplanes and some cars it as a low density