Finding the Concentration of an Acid.

Have a little read: ... Finding the Concentration of an Acid Introduction The extraction of a metal from its ore often produces sulphur dioxide. This is then converted into sulphuric acid, as it is a very soluble gas, and this is then sold as a by-product. The concentration of the sulphuric acid is not known. It is believed to have a concentration of between 0.05moldm-3 and 0.15moldm-3 but the specific concentration is not known. Anhydrous sodium carbonate, a range of indicators and information about them and different types of titration and access to laboratory glassware and equipment is provided. It is the target of this experiment to determine the accurate concentration of the sulphuric acid that is produced from the extraction of the metal from its ore. Background information Extraction of metals The rocks in the earth's crust are a mixture of many different compounds and these rocks are referred to as ores. Metal ores are defined as a mineral that contains enough metal in them so that extraction is worthwhile. Metals are often found as oxides, for example Iron, Aluminium and Copper are all often found combined with oxygen. These metals from the middle part of the reactivity series are also often found as sulphides. Sulphur also occurs in many metal ores, including: * gelena, PbS, * zinc blende, ZnS, * cinnebar, HgS, * stibnite, Sb2S3, * copper pyrites, Cu2S.Fe2S3, and * iron pyrites, Fe2S. * gypsum, CaSO4, and * heavy spar, BaSO4 The extraction of metals from these ores often produces sulphur dioxide. The metals at the top of the reactivity series, for example potassium or sodium, are very reactive and therefore will combine with any non-metals around them and are therefore found in a wide range of compounds such as carbonates, nitrates of phosphates. These elements are unlikely to be found as oxygen as they react with other on-metals instead. Some metals are found native which means that they are uncombined, metals at the bottom of the reactivity series such as gold are platinum are often found native. The type of ore that the element has formed and therefore the method of extraction all depend on its position in the reactivity series. There are many different ways of extracting metals from their ores but all of them involve reduction. Reduction is electron gain. For example consider an ore of zinc known as zinc blende which is mainly zinc sulphide. To become zinc atoms the zinc must gain electrons: Zn2+2e- Zn (reduction by electron gain) In this reaction the sulphur would be separated from the Zinc and may.... The most powerful way of making a metal ion gain electrons is to use electrolysis but this requires a lot of energy Displacement reactions can also be used to remove metals from their ores. A more reactive metal can reduce a less reactive one. This is illustrated through the Thermit process where aluminium is used to extract metals such as chromium or vanadium from their ores. This is economical as the reaction is very exothermic and therefore the heat produced can be used to set up the reaction by heating the furnace. The equation for this reaction is shown below: CR2O3 + 2Al Al2O3 +2Cr In this reaction Aluminium is the reducing agent. All metals are reducing agents, the more reactive a metal, the more powerful it is at bringing about reduction. Carbon in the form of carbon monoxide is used as a reducing agent to extract elements from their ores. It is used in the blast furnace to extract iron from iron ore. Copper is removed from its ore through a process called smelting. First the Chalcopyrite concentrate and some silica is passed with Oxygen enriched air down the heated reaction shaft of the smelter. The iron oxides and sulphides react with the silica to form a molten slag. Copper Sulphide (Cu2S) is formed, the slag is less dense than the Copper Sulphide both substances can be tapped off separately. The Cu2S is then blown with oxygen to form copper and sulphur dioxide: Cu2S + O2 2Cu + SO2 The sulphur dioxide produced is then converted into sulphuric acid as described in the introduction. Sulphur dioxide is also produced when other metals such as lead or zinc are removed from their ores as these metals are often found as sulphides. Their ores are the roasted in air, to produce metal oxide and sulphur dioxide: 2PbS + 3O2 2PbO + 2SO2 The sulphur dioxide is then taken away to a nearby plant where it is converted into sulphuric acid: 2SO2 + O2 2SO3 This is then combined with water as it is a very soluble gas to form sulphuric acid: SO3 + H2O H2SO4 In order to comply with environmental regulations, sulphur dioxide emission from the smelters are collected