chemistry
by Gary Molloy
1. Sulfuric Acid is a clear and odourless yet corrosive gas. Sulfuric acid is the largest volume industrial chemical produced in the world.
1.1. Uses: 1. Agricultural ferlisers (65%), 2. Dyes, alcohols, plastics, rubber, ehter, glue, film, explosives, drugs, paints, food containers, wood preservatives, soaps and detergents, pharmaceutical products, petroleum products, pulp and paper. 3. The common lead-acid storage battery uses Sulfuric acid.
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2. 2. Many industrial processes involve manipulation of equilibrium reactions
2.1. Le Chatelier's Principle. CH4(g) + H2O(l) <--> CO(g) + 3H2(g) Change: Increase concentration of a reactant e.g.[CH4] increases. Effect: Shifts right to use methane, increasing yield of CO and H2. Change:Decrease concentration of a product e.g. remove CO. Effect: Shifts right to make more. Change: Increase pressure (decrease volume). Effect:Shifts left (fewer particles) to drop pressure again. Change: Increase temperature. Effect: Endothermic reaction ( is positive) so equilibrium shifts right to absorb added heat.
3. 5. Saponification is an important organic industrial process
3.1. In the industrial manufacture of soap, tallow (fat from animals such as cattle and sheep) or vegetable fat is heated with sodium hydroxide. Once the saponification reaction is complete, sodium chloride is added to precipitate the soap. The water layer is drawn off the top of the mixture and the glycerol is recovered using vacuum distillation.
3.2. The crude soap obtained from the saponification reaction contains sodium chloride, sodium hydroxide, and glycerol. These impurities are removed by boiling the crude soap curds in water and re-precipitating the soap with salt. After the purification process is repeated several times, the soap may be used as an inexpensive industrial cleanser.
3.3. Saponification is the hydrolysis (Hydrolysis is a chemical reaction during which molecules of water H2O are split into hydrogen cations H+ and hydroxide anions OH− in the process of a chemical mechanism) of an ester under basic conditions to form an alcohol and the salt of a carboxylic acid (carboxylates). Saponification is commonly used to refer to the reaction of a metallic alkali (base) with a fat or oil to form soap. Saponifiable substances are those that can be converted into soap. Marc was here
4. 6. The Solvay process has been in use since the 1860s
4.1. Raw Materials and products: The Solvay Process is a continuous process using limestone (CaCO3) to produce carbon dioxide (CO2) which reacts with ammonia (NH3) dissolved in brine (concentrated NaCl(aq)) to produce sodium carbonate.
4.2. Uses of Sodium Carbonate is mainly used in the production of glass, where a mixture of Na2CO3, CaCO3 and SiO2 (silicon dioxide sand) is used for window or bottle glass. It can also be used as a Water Softening Agent, CO32- from dissolved Na2CO3 can precipitate Mg2+ and Ca2+ ions from hard water as the insoluble carbonates, preventing them from forming a precipitate with soap resulting in scum. For this reason, sodium carbonate is also known as washing soda.
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5. 3. Sulfuric acid is one of the most important industrial chemicals
5.1. The term saponification is the name given to the chemical reaction that occurs when a vegetable oil or animal fat is mixed with a strong alkali. The products of the reaction are two: soap and glycerin. Water is also present, but it does not enter into the chemical reaction. The water is only a vehicle for the alkali, which is otherwise a dry powder.
6. 4. The industrial production of sodium hydroxide requires the use of electrolysis
6.1. The electrolysis of sodium chloride to produce sodium hydroxide and chlorine can be carried out in 3 types of electrolytic cells - mercury, diaphragm and membrane cells. The diaphragm cell is used most, but the membrane cell is becoming more common as it is used in most new plants.
6.2. When a solution is placed in an electrolytic cell, a number of reactions is possible. A sodium chloride solution contains sodium ions, chloride ions and also water, so there is more than one possible reaction at each electrode. Remember that the higher the reduction potential, the more easily the substance is reduced (and thus the greater its oxidising power). The reduction potential of water is higher than the reduction potential of the ions of active metals, so water is often reduced rather than the active metal.
6.3. Electrolysis of sodium hydroxide
6.4. Sodium Hydoxide crystals
6.5. Membrane Cells: The electrolyte solutions in a membrane cell are separated by a cation exchange membrane. This is really an improved diaphragm, allowing Na+ ions to move across, but not allowing OH– ions to cross it. New membranes developed allow the electrodes to be very close to each other, on opposite sides of the membrane. This makes the cell very energy efficient, allowing considerable savings.
7. Industrial chemistry processes have enabled schientists to develop replacements for natural products
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