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Sulfuric Acid
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P Manufacture of paper Di Manufacture of drugs Di Manufacture of dyeshas a... PManufacture of pigments HHousehold D Detergent (manufacture )in... Beats As the electrolyte in car batteries Per Petroleum refining MinuteMetallurgical processes
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75% of the Sulfuric Acid that is produced is used to make fertilisers such as Superphosphate Ammonium sulphate and Ammonium phosphate.
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Rock phosphate contains insoluble Calcium Phosphate. What is the formula for Calcium Phosphate??? Ca 3 (PO 4 ) 2 To be made available to plants it needs to be converted to a soluble form: Ca 3 (PO 4 ) 2, (s) + 2H 2 SO 4 (l) + 4H 2 O Ca(H 2 PO 4 ) 2 (s) + 2CaSO 4 2H 2 O (s)
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Australia has substantial rock phosphate resources, especially in Queensland Australian companies usually import rock phosphate from North Africa. WHY? Cheaper
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H 2 SO 4 (l) + H 2 O (l) HSO 4 - (aq) + H 3 O + (aq) The Ka for this reaction is very high HSO 4 - (aq) + H 2 O (l) SO 4 2- (aq) + H 3 O + (aq) The Ka for this reaction is small These reactions are EXTREMELY exothermic. Because of this it is important to add acid to the water and not the other way around. The reaction is so exothermic that water becomes steam and causes the solution to splutter, causing serious injury.
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Sulphuric acid acts as a catalyst in the following reactions: C 1 2 H 22 O 11 (s) (with H2SO4) 12C (s) + 11H 2 O (l) Is this a condensation reaction, hydrolysis reaction or neither?
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CuSO 4 5H 2 O (s) CuSO 4 (s) + 5H 2 O (l) Sulphuric acid can even be used as a dehydrating agent for gases by bubbling them through the sulphuric acid. However, these gases cannot be bases (i.e. NH 4 ) or reductants. Why?
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What health implication might there be for sulphuric acid being such a strong dehydrating agent?
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If sulfuric acid is spilt on the skin, wash with running water (wink wink, hint hint) If there is a large amount of sulfuric acid, first wipe it off quickly
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A very strong oxidant, especially when hot. H 2 SO 4 can be reduced to SO 2 S or H 2 S : Zn (s) + 2H 2 SO 4 (l) ZnSO 4 (aq) + H 2 O (l) + SO 2 (g) 3Zn (s) + 4H 2 SO 4 (l) 3ZnSO 4 (aq) + 4H 2 O (l) + S (s) 4Zn (s) + 5H 2 SO 4 (l) 4ZnSO 4 (aq) + 4H 2 O (l) + H 2 S (g) However, when zinc reacts with dilute H 2 SO 4 : Zn (s) + H 2 SO 4 (l) ZnSO 4 (aq) + H 2 (g) For each of the reactions above, identify the oxidation numbers of Sulfur.
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The production of H 2 SO 4 usually follows the following process: S SO 2 SO 3 H 2 SO 4 This is know as “The Contact Process”
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Combustion of sulphur recovered from natural gas and crude oil SO 2 formed during the smelting of sulphuric ores of Cu, Zn or Pb It can be mined directly. This is not necessary in Australia
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If solid sulfur is the starting point it is made molten and then sprayed under pressure into a furnace. It will then combust in air to produce SO 2 The high surface area of molten S results in a very fast combustion reaction. S (l) + O 2(g) SO 2 (g) Δ H = -297 kj mol -1 Temperature may reach 1000°C so SO 2 needs to be cooled
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SO 2 is converted to SO 3 with the use of the V 2 O 5 catalyst. 2SO 2 (g) + O 2(g) (with V 2 O 5 ) 2SO 3 (g) Δ H = -197 kj mol -1 Where does this reaction occur? Well, thanks for asking, it occurs in a.....
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SO 2 is mixed with air and passed through trays containing loosely packed porous pellets of the catalyst V 2 O 5 Because the reaction is so exothermic it must continually be cooled The temperature in the converter is maintained at 400 - 500°C and a pressure of 1 atmosphere Nearly complete conversion from sulphur dioxide to sulphur trioxide is achieved. SO?
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Use Le Chatelier’s principle to determine what temperatures and pressure is desired for this reaction. Also, would excess reactants be employed? Excess products? Why/Why not? What about dilution?
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Temperature: Because the reaction is exothermic Le Chatalier predicts the reaction will become more product favoured when the temperature is decreased Because the generation of products decreases pressure, an increase in pressure will push the reaction forward By supplying excess reactants the system will try to re-establish equilibrium by getting rid of those reactants. This will also push the reaction forward.
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What factors will increase the rate of reaction? High Temperature High Pressure The use of a catalyst
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In most instances both a product favoured reaction and a speedy reaction desire the same factors. Excess oxygen is used as the excess reactant Even though increased pressure increases the rate of reaction and pushes it forwards, manufacturers do not bother as high yields are achieved without this costly addition. Le Chatelier dictates that a low temperature will push the reaction forward. However, the rate of reaction will slow with reduced temperature. What to do?!
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Luckily, the catalyst saves the day by making lower temperatures viable. The effect of the catalyst is maximised by spreading it over trays which increases the surface area. The catalyst can become ‘poisoned’ and rendered ineffective by dust. Therefore the air and sulphur dioxide pass through electrostatic precipitators before they enter the converter.
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Absorption of SO 3 SO 3 (g) + H 2 O (l) H 2 SO 4 (aq) Δ H = -130 kj mol -1 Direct reaction with water is very exothermic which results in the formation of steam. Sulfuric acid as a gas is very difficult to collect so an absorption tower is used instead: H 2 SO 4 (aq) + SO 3 (g) H 2 S 2 O 7 (l) This product is called oleum Very little reactant is left. Oleum is then mixed with water: H 2 S 2 O 7 (l) + H 2 O (l) 2H 2 SO 4 (l) Sometimes the reactions occur simultaneously: H 2 SO 4 (aq) + SO 3 (g) + H 2 O (l) 2H 2 SO 4 (l)
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Plants built after 1970 use ‘double desorption’ processes. The unreacted SO 2 is passed back through the catalytic converter. This increases efficiency from 98% to 99.6% SO 2, SO 3 and H 2 SO 4 emissions are continuously monitored. H 2 SO 4 mist is minimised by controlling the operating temperature of the absorber, gas flow rates and concentrations. H 2 SO 4 has a high boiling temperature of 290°C and a low vapour pressure. There is no appreciable air pollution problem with its storage, handling and shipping. Cooling water is usually recycled
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Improvements to conversion have occurred by adding small amounts of cesium to the V 2 O 5 catalyst. This has increased efficiency and allows the reaction to occur at even lower temperatures. Unfortunately the presence of cesium increases the cost of the catalyst by three times. Spent Vanadium is slightly toxic so it needs to be recovered from ‘poisoned’ catalyst before the catalyst is disposed of in landfill.
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“The ‘Contact Process’ actually reduces pollution!” Prove or disprove this statement. 2 minutes 2 reasons
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By using the sulphur by products of other reactions it prevents these pollutants escaping into the atmosphere. This helps to prevent acid rain. Yay! More energy is produced in the process than is used by it. Another yay! This energy is recycled by the plant and can even be sold to other plants for use in chemical manufacture. Sometimes the energy is used to produce ‘green’ electricity.
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Transport procedures need to be in place for loading and unloading H 2 SO 4 is highly corrosive. It is a strong dehydrating agent. It can burn eyes and skin severely. It can cause blindness and 3 rd degree burns. Sulfuric acid mist can cause problems such as pulmonary oedema (fluid in the lungs). Sulphur dioxide and sulphur trioxide are respiratory irritants, damage plants and contribute to acid rain. Oleum is a highly corrosive, oily liquid, that produces SO 3 fumes. These fumes can build up and accidental release procedures need to be in place. Work areas must be well ventilated and employees must wear protective clothing. Acid spills are contained using materials such as earth, clay or sand, then slowly diluted with water before being neutralised with a base (usually CaCO 3 or Na 2 CO 3 )
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What does “P DiDi has a PhD in Beats Per Minute” stand for? What is the name, location of and formula for the catalyst that is used? Vanadium Pentoxide, Converter, V2O5 What is the chemical formula for Oleum? H2S2O7 Which reaction occurs in the ‘converter’? SO2 to SO3 What two reactions need to occur for the adsorption of sulfur trioxide? SO3 + H2SO4 H2S2O7 H2S2O7 + H2O 2H2SO4 How is sulfur converted to sulfur dioxide? Molten sulfur is sprayed into the air Write the formula for the production of superphosphate
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http://www.youtube.com/watch?v=zTLiJE-j1-I
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From Chapter 22 Answer: Q 2, 3, 5, 6, 7, 8, 9, 10, 11, 13, 15 You will have a SACT test on sulfuric acid and its production next Monday, so get studying!
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