Presentation on theme: "Module 2 Rock Cycle Metals The Air. Uses of Metals Iron is used for girders, transport and cutlery. Copper is used in coinage, water pipes, electrical."— Presentation transcript:
Module 2 Rock Cycle Metals The Air
Uses of Metals Iron is used for girders, transport and cutlery. Copper is used in coinage, water pipes, electrical wiring and ornaments. Aluminium is used for window frames, aircraft and pans.
Extracting Metals from Ores The most reactive metals are most difficult to extract from their ores. The least reactive metals are the easiest to extract from their ores. REDUCTION Reduction is the loss of oxygen from a compound. Copper oxide + Carbon heat Copper + Carbon dioxide REDUCTION
Purification of copper and half-equations. The anode is made of impure copper and the cathode is made of pure copper. At the anode (+) copper ions pass into solution. At the cathode (-) copper atoms are deposited. The solution must contain copper ions and is usually copper (II) sulphate. Half Equations. The reactions at the electrodes can be written as half-equations. This means that we write separate equations for what is happening at each of the electrodes during electrolysis. For the purification of copper by electrolysis. At the CATHODE (-): Cu e - REDUCTION Cu Blue copper (II) solution gains two electrons pinky brown copper metal At the ANODE (+): Cu OXIDATION Cu e - Copper metal blue copper (II) solution loses two electrons The solution of copper sulphate does not alter in concentration during the process, if everything is working as it should. The copper atoms change to copper(II) ions and leave the anode to go into solution at just the same rate that copper (II) ions arrive at the cathode and change into copper atoms.
TRANSITION METALS In general the transition metals… have high melting points have high densities are good conductors of electricity and heat often form coloured compounds Some of them are in common use eg. Wires, pans,girders, ornaments, cars, jewellery.
Rocks and the Rock Cycle IGNEOUS SEDIMENTARYMETAMORPHIC Rocks, classify the following rocks; GRANITE LIMESTONE SLATE BASALT MARBLE SANDSTONE Process 1 & 5 - the rock melts to form MAGMA, which wells up from the MANTLE and COOLS DOWN either ABOVE or WITHIN the Earth’s crust. Features; a hard rock consisting of interlocking crystals which are large if the rock has cooled slowly and small if it has cooled quickly. Process 2 & 6 - made from layers of SEDIMENT whose weight squeezes out WATER causing particles to become CEMENTED together, YOUNGER rocks therefore are usually on top. Features; a grainy and crumbly rock which sometimes contains fossils by which the rock can be dated Process 3 & 4 - the rock is formed by extreme TEMPERATURE and PRESSURE caused by MOUNTAIN BUILDING processes which force SEDIMENTARY rocks deep underground near to MAGMA where they are COMPRESSED and HEATED changing their TEXTURE and STRUCTURE. They can be formed from any rock type. Features; usually hard rocks containing tiny crystals on cooling, could contain distorted fossils. They are chemically identical to the rocks they are formed from.
The Earth’s Atmosphere. 4 billion years ago Present day 2.5 billion years ago Volcanic activity releases mainly CARBON DIOXIDE, and smaller amounts of hydrogen, carbon monoxide and nitrogen with WATER VAPOUR which condenses as the Earth cools to form the oceans. Primitive green plants evolve and CARBON DIOXIDE is reduced as plants take it in and release OXYGEN microorganisms which can’t tolerate OXYGEN die off carbon from CARBON DIOXIDE is locked up in sedimentary rocks as carbonates and fossil fuels. Carbonates are formed as a result of carbon dioxide dissolving in the oceans. More NITROGEN is added to the atmosphere as a result of DENITRIFYING BACTERIA on nitrates from decaying plant materials. The oxygen in the atmosphere is now much increased Some of it is converted to OZONE which protects animals from the full extent of the Sun’s UV radiation. New species evolve. There is a state of balance because PHOTOSYNTHESIS produces oxygen in sunlight. RESPIRATION and BURNING FUELS use oxygen and produce carbon dioxide. Carbon dioxide is absorbed by the SEAS and OCEANS
Limestone, Thermal Decomposition and limewater Calcium Carbonate CaCO 3 Calcium Oxide CaO Calcium hydroxide Ca(OH) 2 It can be used as a neutralising agent. It is used in glass making, cement making and in the Blast furnace It is decomposed by heat to form calcium oxide, also known as quicklime. When water is added to quicklime, slaked lime is produced. Both these products can be used to neutralise acid in soils. When slaked lime is dissolved in water, limewater is produced. Limewater reacts with carbon dioxide to form Calcium carbonate. This is the test for Carbon dioxide. Carbon dioxide CO 2 Limestone is mainly Calcium Carbonate.
Limestone is a sedimentary rock. It comes from the shells of sea creatures or from solids formed in the oceans long ago. It is mostly made of calcium carbonate - CaCO 3. It is an important raw material for both the chemical and the construction industries. Limestone
Limestone for soil Acidity can build up in soils. This can inhibit the growth of many crops. Consequently farmers need to adjust the pH back towards neutral. Limestone provides a cheap way of neutralising soil acidity. Limestone is used in agriculture. 765 pH
Limestone - extraction of iron Limestone is one of three major raw materials used to extract iron from its ores. It reacts with acidic impurities changing them into a slag that separates from the iron. In the blast furnace limestone removes acidic earthy impurities that would ruin the quality of iron. CaCO 3 + SiO 2 CaSiO 3 + CO 2
Quicklime - the lime kiln Limestone is heated in huge ovens known as lime kilns. The calcium carbonate decomposes into calcium oxide (quicklime) and carbon dioxide. Quicklime is a vital ingredient of cement, concrete and of most types of glass. CaCO 3 CaO + CO 2
Slaked lime If water is added to quicklime the calcium oxide changes into calcium hydroxide (slaked lime). Slaked lime is a vital ingredient of various building materials. CaO + H 2 O Ca(OH) 2 A solution of calcium hydroxide (limewater) is also used to test for carbon dioxide gas (it goes cloudy).
Manufacture of cement The main raw materials for cement are limestone and clay. A small amount of gypsum is also added to help the cement set at the right speed. Clay or shale Limestone or chalk Gypsum (calcium sulphate) heat Cement
Cement, concrete and mortar To make concrete cement is mixed with small stones or gravel. Mortar consists of cement mixed with calcium hydroxide. This makes a smooth slow setting mixture suitable for bricklaying Cement, concrete and mortar all set when interlocking crystals grow between cement particles joining them together.
Manufacture of glass Limestone, sand and sodium carbonate are the raw materials used to make most glass. Limestone Lime (calcium hydroxide) Sand (silicon dioxide) Sodium carbonate heat water Glass heat