Antipyretics for children are prescribed by a pediatrician. But there are situations of emergency care for fever, when the child needs to give the medicine immediately. Then the parents take responsibility and apply antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? Which medications are the safest?
Calcium oxide can also be determined by the volumetric method. The course of this determination, inclusive, before obtaining in oxalate calcium oxalate is the same as in the previous case. The precipitate dissolves in sulfuric acid; Isolated oxalic acid is titrated with a solution of potassium permanganate. [ ...]
Calcium carbonate (CaCO3) does not dissolve in water, except when it contains carbon dioxide. He heated to red heat in a lime kiln, he emits carbon dioxide (CO2) and turns into calcium oxide (CaO). This oxide is called quicklime and is often used as a soil improver or fertilizer. For convenience, in this chapter, all data are based on calcium oxide (CaO) and magnesium oxide (MgO), rather than calcium (Ca) and magnesium (Mg). [ ...]
Calcium carbonate (chalk), in which calcium oxide gradually turns during storage of lime, has a relatively mz value for plant protection. It is impossible to obtain a Bordeaux liquid from chalk; it does not form calcium polysulphides during boiling with sulfur, does not improve the toxic properties of anabasine sulfate, etc. Chalk, like lime, can not be used together with soaps. [ ...]
With the addition of water, calcium oxide energetically combines with it; lime after a while (within the limits of the first 10-30 minutes) is strongly heated, and its pieces crumble into a light white powder. If excess water is taken, then a semi-liquid or liquid mass is obtained instead of the powder. [ ...]
The calcium oxide resulting from the reaction should be removed by washing with a weak solution of hydrochloric acid. [ ...]
From the difference in the weight of the empty crucible and the crucible with calcium, the weight of the filter ash is subtracted, the difference is multiplied by 2 and calcium oxide is found (in mg / l). [ ...]
In the case of dust, free calcium oxide was taken into account, in the case of slags (ferrochrome production and open-hearth), the total content of calcium oxide and magnesium oxide (usually 50-60%). [ ...]
One of the constituent parts of the cement is calcium oxide CaO, which, after mixing with water and hydration, is converted to Ca (OH) 2 calcium hydroxide. The impact on sulfuric acid concrete causes the formation of new calcium compounds, which are characterized by a strong increase in volume, which leads to the destruction of concrete. This type of corrosion is most common in sewer canals. [ ...]
Lime method. In order to completely separate gallium from aluminum and minimize the precipitation of gallium with tricalcium hydroaluminate, it is necessary to divide in time the causticization operations of carbonate and bicarbonate alkali and dissolve gallium and aluminum oxides in a NaOH solution and an aluminum precipitation operation. This is achieved by introducing lime into the pulp in two steps. If you first mix the pulp with the amount of lime that is needed only for causticizing CaO: NaaO = 1: 1 mol, then most of the aluminum and gallium will pass into the solution. [ ...]
The acidimetric method is based on the precipitation of calcium in the form of oxalic acid, its salt, which is then calcined, obtaining calcium oxide as a result of the decomposition of oxalate. The formed calcium oxide is dissolved in water and titrated with acid. [ ...]
Toxicity to humans. Dusty calcium hydroxide, and especially calcium oxide, causes irritation of the mucous membranes. Unexpired lime, getting on the skin, causes severe burns. It is very dangerous to get quicklime into the eyes, which can lead to clouding of the cornea. [ ...]
By controlled addition of water to calcium oxide (quicklime). [ ...]
Lime without chlorous iron is rarely used, as calcium oxide is in itself an inefficient coagulant for coagulating sediment. [ ...]
In such cases, the data of titration with hydrochloric acid, recalculated for calcium oxide, should be considered not as a carbonate hardness, but as a general alkalinity, expressed in degrees of rigidity. [ ...]
To calculate the total hardness, you need to convert the amount of milligrams of magnesium oxide into calcium oxide, ie multiply by 71: 71.1-1.4 = 99.5. To express milligrams in degrees of stiffness, 99.5 divide by 10 (99.5: 10 = 9.95 ° of magnesian stiffness). [ ...]
Instead of lime specially introduced into the water before the lime settling tanks, it would be possible to use calcium oxide contained in the sewage from the casting machines of cast iron, by mixing sewage with the converter gas purification before it enters the sedimentation tanks. Until now, alkalization of water before the gas treatment was not carried out at any plant. [ ...]
Burnt lime (burnt, lime) is obtained by calcining limestones, while calcium carbonate passes into calcium oxide. Before entering the soil, burnt lime is usually quenched (one part by weight of water in three parts of lime). When quenching freshly-burned lime with water, it passes into slaked lime (puschku). Extinguishing of lime can also be carried out by leaving it for 1-2 months in piles covered with earth. Particularly strong effect burnt lime has on heavy sod-podzolic and gray forest soils. [ ...]
F. Vogel describes another method of regeneration. The lime sulphate processed by lime is converted to calcium sulphate, which is settled, filtered, dehydrated and incinerated. In this case, calcium oxide and sulfur dioxide are formed. Thus, sulfuric acid and lime are obtained from sodium sulfate. When calcium dehydrated calcium sulfate is combined with silicic acid, it is possible to obtain calcium silicate, which is a valuable material for the production of cement. [ ...]
Desiccants can be oxides and salts of certain metals, for example lead oxides (glue and suricum), lead acetate, calcium oxide, zinc oxide, etc. [ ...]
To intensify the process of water clarification (NF Sokolova and II Troitsky, 1971), it is recommended to add potassium permanganate, calcium oxide, clay and other substances. The presence of small amounts (1-3 mg / l) of potassium permanganate somewhat improves the efficiency of water disinfection from spores during chlorination and coagulation with sulfuric acid alumina. [ ...]
D, for neutralization of spent etching solutions without a liquid phase, prepare a calcareous dough or lime-puschku. -. Calcium oxide (CaO) in burnt lime and lime milk is determined by a known method. [ ...]
The reaction of aldol condensation of formaldehyde is particularly complete when using calcium hydroxide as an alkaline agent and a temperature above 60 ° C. It is believed that calcium oxide not only provides the necessary alkalinity of the medium, but is also an important component of the intermediate complex formed during the condensation of formaldehyde. [ ...]
Chemical analysis showed that soft deposits consist mainly of ferric oxide (up to 45% Fe203) and oxide (up to 20% FeO), calcium oxide (up to 9-10% CaO), silica (about 8% Si02), alumina (about 3-4% Al2O3) and carbon in the form of fine coke particles (about 4%). Solid deposits consist mainly of calcium oxide (up to 40-50% CaO), they contain moderate amounts of iron, carbon, silicon oxide, aluminum oxide, etc. Viscous deposits contain up to 33% ZnO, as well as oxide and za- ferrous iron (20-35%) and silica (up to 7-13% Si02); they also contain calcium oxide (about 10-14% CaO), aluminum oxide, etc. Calcium carbonate formation (CaCO3), which is an astringent substance for iron and other mechanical impurities precipitated in the pipeline, should be considered as the cause of deposits in the slurry lines. [ ...]
Burnt, or lumpy, lime is obtained by burning hard limestones, while carbonates lose carbon dioxide and turn into calcium oxide and magnesium, the content of which in lime reaches 100%. [ ...]
Lime is treated by heating with titrated hydrochloric acid. Part of it is spent on the formation of neutral salts of calcium and magnesium. By the amount of hydrochloric acid bound by bases, the content of the sum of oxides, hydroxides and carbonates is calculated, expressing them in terms of calcium oxide or calcium carbonate as a percentage of the weight of lime. [ ...]
The washed precipitate on the filter of aqueous aluminum oxides and iron precipitated after the addition of ammonia and ammonium chloride in the study of water on calcium oxide, dried is burned together with a filter, calcined in a calcined and suspended crucible. The residue in the filter after calcination will consist of anhydrous alumina and iron oxides, as well as filter ashes. If the water in the determination of calcium oxide was taken 500 ml, then the weight of the oxides is multiplied by 2. From the total amount of anhydrous iron and aluminum oxides, the weight of iron recalculated in anhydrous iron oxide is subtracted. This difference gives the amount of alumina in milligrams per liter. [ ...]
Stabilization of the mixture of alkaline and sea water proceeds slowly. According to the laboratory data of Asylitium II, in the first hour, 109 mg / l, calculated on calcium oxide, 109 mg, then the intensity of the process gradually decreases and practically ends during ö-S hours (at 46-74 mg / L of residual CaO). [ ...]
In the water softening process, 200 tons of sludge with a specific gravity of 1.5 is obtained, with 15% (by weight) of the slurry consisting of solid particles, which are calcium and magnesium salts. Since calcium salts form calcium oxide during calcination, which can be used in the process of water softening, the pre-compacted slurry is sent to the furnace. In this process, 70% of the solid slurry material is separated during the compaction (centrifugation), the compacted slurry-fugate-contains 65% (by weight) of the solid material. [ ...]
For the preparation of lime milk requires burnt lime and water. Burned lime is burned with limestone, which consists mainly of calcium carbonate CaCO3. The main and active part of burnt lime is calcium oxide CaO, impurities in it contain sand, clay, limestone and other substances. [ ...]
The optimal reagent costs were 4-4-6 l / m3 for sulfuric acid, 30-40 l / m3 for the waste pickling solution and 2-4 kg / m3 for calcium lime for lime milk. [ ...]
In the case of a high content of carbon dioxide in the sample, it is recommended that the chemical analysis determine additionally the content of silicic acid (SiO2), sesquioxides (H2O3), iron total, calcium oxide, magnesium oxide and sulfates. From the data obtained, calculate the content of calcium carbonate (CaCO3) and magnesium carbonate in the sample. [ ...]
The removal of cobalt, aluminum, iron, zinc and copper from the drain was carried out by liming, followed by the separation of the precipitated precipitate. Lime milk containing active calcium oxide in an amount of 50-60 grams per liter was added until a pH value in the range of 9-10 was established, which provided optimal conditions for the precipitation of hydroxides of the above metals. Their residual concentrations in the runoff were much lower than the initial concentrations. As a result of liming, the total content of organic substances in the sink decreased only slightly compared with the initial value, although the concentration of benzene decreased by half (see Table). [ ...]
The waste of the metallurgical industry - the Thomas slag represents a valuable source of phosphorus for agriculture. It is obtained by processing iron ores rich in phosphorus. In converters, where the metal is melted, calcium oxide is added to bind the phosphorus anhydride formed during the combustion of the reduced phosphorus (temperature 1800-2000 °). [ ...]
Manganese deposits are found in the Trans-Urals and the Urals of the Republic. In the Trans-Urals, deposits of manganese ore are located in Uchalinsky, Abzelilovsky and Baymak districts. The content of manganese in ores reaches 25-35%. In addition to manganese, they contain silica, calcium oxide and iron compounds. In small quantities, there is phosphorus. [ ...]
In the presence of too soft water full decomposition of alumina does not occur, and it can fall out in the form of basic salts or remain undecomposed, which changes the taste of water. Therefore, to very soft water it is necessary to add soda Ma2C03 or lime water Ca (OH) 2 or calcium oxide in an appropriate amount (the calculation is done depending on the degree of alkalinity of water). [ ...]
Interesting studies were carried out at VNIIA VODGEO to intensify the process of dehydration of sewage sludge from etching and galvanic compartments by using ferrochromic slag (FHSH) - a waste of electrometallurgical production. The main constituents of FHC are: 48-54% of calcium oxide; 18-22% silicon dioxide, 7.8-11% magnesium oxide, 2-7.7% chromium oxide. Neutralizing ability is mainly possessed by dicalcium silicate and free calcium oxide. [ ...]
The ash of wood partially dissolves in water. Soluble part - from 10 to 25% of the total ash content - consists mainly of potassium and sodium carbonate (about 2/3 soluble parts) and carbonates of other metals, as well as soluble salts of sulfuric, hydrochloric and silicic acids. Of the insoluble substances, the most important are calcium oxide, silicates, phosphates and oxides of iron, magnesium and manganese. [ ...]
The slurry contained in the waste water is deposited at 95-99% with a hydraulic size and = 0.2 mm / s. With such a hydraulic. and the high content of iron in it, it is advisable to purge the wastewater from mechanical impurities in hydrocyclones. Then it is recommended to neutralize water with lime milk or by mixing with sewage from casting machines containing calcium oxide (lime). As a result of neutralizing the acid in waste water and simultaneously purifying them from manganese by precipitating it in an alkaline medium in the form of manganese hydroxide [Mn (OH) 2], passing it through rapid oxidation to insoluble hydrate Mn (OH) 4, the neutralized and clarified water. Neutralization of these wastewater can also be carried out together with neutralization of spent pickling solutions and washing water. [ ...]
The aluminate solution, after separation from the autoclave sludge, is desiliconized in the presence of a recycled white slurry at a temperature of about 105 ° C. For 6 hours, the silica module rises from 30 to -100. [ ...]
In addition to simple superphosphate, a more concentrated double superphosphate containing from 38 to 50% P2O5 in the form of mainly water-soluble monocalcium phosphate is used. Phosphorus fertilizer for ponds can be a tomaslag containing at least 14% P2O5. To fertilize them, as well as precipitate and phosphorite flour, it is more expedient to use ponds with acidic reaction of water, and also located on light soils. In addition to phosphoric acid, the composition of thomaslag includes calcium oxide (48%), manganese oxide (13% :), silica, iron oxide and sulfur. [ ...]
Solubility of solids in liquids. The solubility of solids in water varies widely. In the vast majority of cases, as the temperature increases, it increases. However, there are exceptions to this rule. For example, CaS04-2H20 gypsum loses up to 75% of crystallization water upon heating and its solubility decreases. At a temperature of about 200 ° C, semi-aquatic gypsum is practically insoluble in water. This explains its loss at high temperatures on the walls of heat exchangers in the form of scale. Their solubility decreases with increasing temperature, calcium oxide CaO, lithium carbonate Li2C03, and others. [ ...]
When Parker, Patder and Ritter burned linden wood and examined the untouched skeletons of microtome sections that were not exposed to various acids, they came to the conclusion that the inorganic substance is located both in the secondary wall of the cell and in the median plate. This partially confirmed the work of Uber and Goodspeed, who found the mineral components in the entire cell wall (secondary), but doubted that they exist in the middle plate. However, in contrast to the siliceous skeletons of Brown, X-ray diffraction patterns of lime ash showed only randomly oriented calcium oxide and calcium carbonate. [ ...]
It has been observed that the sewage purified by this method is poorly clarified, remains cloudy and contains from 3.2 to 6.8 mg / l of nickel (when determined in standing water). To improve coagulation and precipitation, it is recommended to add trivalent iron FeCl3 in quantities equal to the initial concentration of nickel (in terms of Fe3 +) to the wastewater that is purified by calcareous milk. In Table. 61 shows the data on the purification of nickel-containing wastewater reagent method. It can be seen from the table that for the wastewater containing 25 mg / l nickel cations in solution and having a pH of about 6, the optimum lime dose in terms of active calcium oxide is 100 mg / l and ferric iron 25 mg / l. [ ...]
The production of bound nitrogen from atmospheric air in plasma reactors is intensively studied both in our country and abroad, especially in the last 10 years. While the plasma method for all indicators is inferior to ammonia, primarily in the consumption of electricity, which is about 7-10 times higher. However, the difference becomes less noticeable if the plasma process is combined with the decomposition of phosphorus-containing raw material in an air atmosphere with simultaneous fixation of nitrogen. Further processing makes it possible to obtain a mixture of phosphorus and nitric acids from phosphorus pentoxide and nitrogen oxides for the production of complex fertilizers. Certain prospects are emerging for the utilization of other components of phosphorus-containing raw materials. With the dissociation of the phosphorus-containing raw material in the plasma, it practically completely defolves and releases silicon tetrafluoride. In addition, there is no need to process phosphogypsum, as is the case with sulfuric acid phosphate processing, since calcium oxide is formed in the plasmochemical process. By varying the temperature of the plasmochemical process, it is possible first to defolorize the phosphorus-containing feedstock, and then at a higher temperature (about 3500 K) to convert it to phosphorus pentoxide or to obtain elemental phosphorus, silicate and calcium carbide and carbon monoxide in the presence of additives (for example, silica and carbon) .
Calcium oxide, the formula CaO, is often called quicklime. This publication will tell you about the properties, the preparation, as well as the use of this substance.
Definition
Calcium oxide is a white crystalline substance. In some sources, it can be called calcium oxide, quicklime, "boiling water" or kirabite. Unexpired lime is the most popular trivial name for this substance. It is the only and highest calcium oxide.
Properties
The oxide is a crystalline substance having a cubic face-centered crystal lattice. 
It melts at a temperature of 2570 ° C, and boils at 2850 ° C. This is the basic oxide, its dissolution in water leads to the formation of calcium hydroxide. The substance can form salts. To do this, it must be added to the acid or acid oxide.
Receiving
It can be obtained by thermal decomposition of limestone. The reaction proceeds as follows: calcium carbonate gradually heated, and when the temperature of the medium reaches 900-1000 ° C, it decomposes into a gaseous tetravalent carbon monoxide and the desired substance. Another way of obtaining it is the simplest reaction of the compound. To do this, a small amount of pure calcium is lowered into liquid oxygen, followed by a reaction, the product of which becomes the desired oxide. Also, the latter can be obtained during the decomposition of calcium hydroxide or calcium salts of certain oxygen-containing acids at high temperatures. For example, consider the decomposition of the latter. If you take calcium nitrate (the remainder is taken from nitric acid) and heat it to 500 ° C, then the products of the reaction will be oxygen, nitrogen dioxide and the desired calcium oxide.
Application
Basically, this substance is used in the construction industry, where it produces silicate bricks. Previously, calcium oxide was used in the manufacture of lime cement, but soon the latter ceased to operate due to absorption and accumulation of moisture by this compound. And if it is used for masonry of the furnace, then incandescent carbon dioxide will be incandescent in the room. Also, the substance currently under discussion is known to be resistant to water. Because of this property, calcium oxide is used as a cheap and affordable refractory. This compound is necessary in any laboratory when drying non-reactive substances. Calcium oxide in one of the industries is known as food additive Е529. Also, a 15 percent solution of this substance is needed to remove sulfur dioxide from certain gaseous compounds. With the help of calcium oxide, they also produce "self-heating" utensils. This property is provided by the process of heat release during the reaction of calcium oxide with water.
Conclusion
That's all the basic information about this connection. As mentioned above, it is often called quicklime. And do you know that the concept of lime in chemistry is very loose? There are also slaked, chloric and sodium lime.
Calcium oxide is a crystalline compound of white color. Other names of this substance are quicklime, calcium oxide, "kirabit", "kipelka". Calcium oxide, the formula of which CaO, and its product of interaction with (H2O) water - Ca (OH) 2 ("pushers", or hydrated lime) have found wide application in the construction industry.
How is calcium oxide obtained?
1. The industrial method of obtaining this substance is the thermal (under the influence of temperature) decomposition of limestone:
CaCO3 (limestone) = CaO (calcium oxide) + CO2 (carbon dioxide)
2. Also calcium oxide can be obtained through the interaction of simple substances:
2Ca (calcium) + O2 (oxygen) = 2CaO (calcium oxide)
3. The third method of obtaining calcium oxide is the thermal decomposition of calcium hydroxide (Ca (OH) 2) and calcium salts of several oxygen-containing acids:
2Ca (NO3) 2 = 2CaO (the resultant substance) + 4NO2 + O2 (oxygen)
calcium oxide
1. Appearance: a crystalline compound of white color. Crystallized by the type of sodium chloride (NaCl) in a cubic crystal face-centered lattice.
2. The molar mass is 55.07 g / mol.
3. The density is 3.3 grams / centimeter³.
The thermal properties of calcium oxide
1. The melting point is 2570 degrees
2. The boiling point is 2850 degrees
3. The molar heat capacity (under standard conditions) is 42.06 J / (mol · K)
4. The enthalpy of formation (under standard conditions) is -635 kJ / mol
Chemical properties of calcium oxide
Calcium oxide (formula CaO) is the basic oxide. Therefore, he can:
Dissolve in water (H2O) with release of energy. In this case, calcium hydroxide is formed. This reaction looks like this:
CaO (calcium oxide) + H2O (water) = Ca (OH) 2 (calcium hydroxide) + 63.7 kJ / mol;
React with acids and acid oxides. In this case, salts are formed. Here are examples of reactions:
CaO (calcium oxide) + SO2 (sulfurous anhydride) = CaSO3 (calcium sulphite)
CaO (calcium oxide) + 2HCl (hydrochloric acid) = CaCl2 (calcium chloride) + H2O (water).
Application of calcium oxide:
1. The main volumes of the substance we are considering are used in the production of silicate bricks in construction. Previously, quicklime was used as lime cement. It was obtained by mixing it with water (H2O). As a result, calcium oxide was converted to hydroxide, which then, after absorbing from the atmosphere (CO2), hardened, turning into calcium carbonate (CaCO3). Despite the cheapness of this method, at present lime cement is practically not used in construction, since it has the ability to absorb and accumulate liquid in itself.
2. As a refractory material, calcium oxide is suitable as an inexpensive and affordable material. Fused calcium oxide has a resistance to water (H2O), which allowed it to be used as a refractory where the use of expensive materials is impractical.
3. The laboratories use a higher calcium oxide to dry out those substances that do not react with it.
4. In the food industry, this substance is registered as a food additive under the designation E 529. Used as an emulsifier to create a homogeneous mixture of immiscible substances - water, oil and fat.
5. In industry, calcium oxide is used to remove sulfur dioxide (SO2) from flue gases. Apply, as a rule, 15% water solution. As a result of the reaction in which slaked lime and sulfur dioxide react, gypsum CaCO4 and CaCO3 are obtained. During the experiments, the scientists achieved the indicator in 98% of the smoke cleaning from sulfur dioxide.
6. Used in special "self-heating" dishes. A container with a small amount of calcium oxide is located between the two walls of the vessel. When the capsule is pierced in water, a reaction begins with the release of a certain amount of heat.
Oxide and Calcium Hydroxide - Chemistry, Cheat Sheet for Inorganic Chemistry Calcium Oxide (Cao) - Uncured or Burnt Lime ...
Calcium oxide (CaO) - quicklime or burnt lime- a white fire-resistant substance formed by crystals. Crystallized in a cubic face-centered crystal lattice. The melting point is 2627 ° C, the boiling point is 2850 ° C.
It is called burnt lime because of the way it is produced - calcination of calcium carbonate. Firing is carried out in high shaft furnaces. The furnace is laid with layers of limestone and fuel, and then lit from below. At incandescence the decomposition of calcium carbonate takes place with the formation of calcium oxide:
Since the concentrations of substances in the solid phases are unchanged, the equilibrium constant of this equation can be expressed as follows: K =.
In this case, the gas concentration can be expressed by its partial pressure, that is, the equilibrium in the system is established at a certain pressure of carbon dioxide.
The dissociation pressure of the substance- the equilibrium partial pressure of the gas, obtained when the substance is dissociated.
To provoke the formation of a new portion of calcium, you need to raise the temperature or remove part of the resulting CO2 , while the partial pressure decreases. By maintaining a constant lower partial pressure than the dissociation pressure, a continuous calcium production process can be achieved. For this, when roasting lime in the ovens make good ventilation.
Receiving:
1) in the interaction of simple substances: 2Ca + O2 = 2CaO;
2) with the thermal decomposition of hydroxide and salts: 2Ca (NO3) 2 = 2CaO + 4NO2? + O2 ?.
Chemical properties:
1) interacts with water: CaO + H2O = Ca (OH) 2;
2) reacts with nonmetallic oxides: CaO + SO2 = CaSO3;
3) dissolves in acids, forming salts: CaO + 2HCl = CaCl2 + H2O.
Calcium hydroxide (Ca (OH) 2 - hydrated lime, pusher)- a white crystalline substance, crystallizes in a hexagonal crystal lattice. Is a strong base, poorly soluble input.
Calcareous water- a saturated solution of calcium hydroxide, which has an alkaline reaction. In air, it becomes turbid as a result of carbon dioxide absorption, forming calcium carbonate .
Receiving:
1) is formed by dissolving calcium and calcium oxide input: CaO + H2O = Ca (OH) 2 + 16 kcal;
2) by the interaction of calcium salts with alkalis: Ca (NO3) 2 + 2NaOH = Ca (OH) 2 + 2NaNO3.
Chemical properties:
1) when decomposed to 580 ° C decomposes: Ca (OH) 2 = CaO + H2O;
2) reacts with acids: Ca (OH) 2 + 2HCl = CaCl2 + 2H2O.
End of work -
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Cheat Sheet for Inorganic Chemistry
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Phosphoric anhydride corresponds to several acids. The main one is orthophosphoric acid H3PO4. Phosphoric acid dehydrated is presented as a colorless transparent crystal
Mineral Fertilizers
Mineral fertilizers are inorganic substances, mainly salts, including plant nutrients necessary for plants and used to increase fertility
Carbon and its properties
Carbon (C) is a typical non-metal; in the periodic system is in the 2nd period of the IV group, the main subgroup. Sequence number 6, Ar = 12,011 amu, the charge of the nucleus +6.
Allotropic modifications of carbon
Carbon forms 5 allotropic modifications: cubic diamond, hexagonal diamond, graphite and two forms of carbine. Hexagonal diamond is found in meteorites (mineral
Carbon oxides. carbonic acid
Carbon with oxygen forms oxides: CO, CO2, C3O2, C5O2, C6O9, etc. Carbon monoxide (II) - CO. Physical properties: carbon monoxide, b
Silicon and its properties
Silicon (Si) is in the 3rd period, the IV group of the main subgroup of the periodic system. Physical properties: silicon exists in two modifications: amo
There are three types of internal structure of primary particles.
1. Suspensoids (or irreversible colloids) are heterogeneous systems whose properties can be determined by a developed interphase surface. Compared with suspensions, more highly disperse
Salts of silicic acid
The general formula of silicic acids is n SiO2? M H2O. In nature they are mainly in the form of salts, in the free form there are few, for example, HSiO (ortok
Production of cement and ceramics
Cement is the most important material in construction. Cement is obtained by firing a mixture of clay with limestone. When roasting a mixture of CaCO3 (calcined soda)
Physical properties of metals
All metals have a number of common, characteristic properties for them. Common properties are: high electrical conductivity and thermal conductivity, plasticity. Spread of parameters in met
Chemical properties of metals
Metals have a low ionization potential and affinity for the electron, therefore in chemical reactions they act as reducing agents, in solutions form
Metals and alloys in engineering
In a periodic system of 110 known elements, 88 are metals. In the 20th century, with the help of nuclear reactions, radioactive metals were obtained which are not creatures
Basic methods of obtaining metals
A large number of metals is found in nature in the form of compounds. Natural metals are those that occur in a free state (gold, platinum, p
Corrosion of metals
Corrosion of metals (corrosio - corrosion) - the physico-chemical reaction of metals and alloys with the environment, as a result of which they lose their properties. The basis for
Protection of metals against corrosion
Protection of metals and alloys against corrosion in corrosive environments is based on: 1) increased corrosion resistance of the material itself; 2) reducing aggression
General characteristics of the lithium subgroup
The subgroup of lithium is group 1, the main subgroup includes alkali metals: Li-lithium, Na-sodium, K-potassium, Cs-cesium, Rb-rubidium, Fr-france. Common electron
Sodium and potassium
Sodium and potassium-alkali metals, stand in group 1 of the main subgroup. Physical properties: similar in physical properties: light silvery
Caustic alkali
Alkalis form alkali metal hydroxides of the 1 group of the main subgroup when they are dissolved in water. Physical properties: solutions of alkalis in water are softer for more
Salts of sodium and potassium
Sodium and potassium form salts with all acids. The salts of sodium and potassium are very similar in chemical properties. A characteristic feature of these salts is good solubility in water, therefore
General characteristics of the beryllium subgroup
The beryllium subgroup includes: beryllium and alkaline earth metals: magnesium, strontium, barium, calcium and radium. The most common in nature in the form of compounds,
Calcium
Calcium (Ca) - the chemical element of the second group of the periodic system, is an alkaline earth element. Natural calcium consists of six stable isotopes. Conf
Water hardness and ways to eliminate it
Since calcium is widely distributed in nature, its salts are found in large quantities in natural waters. Water, which has in its composition the salts of magnesium and calcium, is called
General characteristics of the boron subgroup
The external electronic configuration for all elements of the subgroup is s2p1. A characteristic property of subgroup IIIA is the complete absence of metallic properties of boron and ti
Aluminum. The use of aluminum and its alloys
Aluminum is located in the 3rd group of the main subgroup, in the 3rd period. The atomic number is 13. The atomic mass is ~ 27. P-element. Electronic configuration: 1s22s22p63s23p1.On the outside
Aluminum oxide and hydroxide
Aluminum oxide - Al2O3. Physical properties: aluminum oxide - white amorphous powder or very solid white crystals. Molecular weight = 101.96, density - 3.97
General characteristics of chromium subgroup
The elements of the subgroup chromate an intermediate position in the series of transition metals. They have high melting and boiling points, free places on electronic
Oxides and hydroxides of chromium
Chromium forms three oxides: CrO, Cr2O3 and CrO3. Chromium oxide II (CrO) - basic oxide - black powder. A strong reducing agent. CrO is dissolved in dilute hydrochloric acid
Chromates and dichromates
Chromates are salts of chromic acid Н2Сг04, existing only with aqueous solutions with a concentration of not more than 75%. Valence of chromium in chromates - 6. Chromate
General characteristics of the iron family
The iron family is part of the subgroup of the eighth group and is the first triad, including iron, cobalt nickel
Iron compounds
Iron oxide (II) FeO-black crystalline substance, insoluble in water and alkali. FeO corresponds to the base of Fe (OH) 2.
Domain process
Domain process-melting of pig iron in a blast furnace. The blast furnace is laid out with refractory bricks of 30 m in height and 12 m in internal diameter. The upper half - w
Cast iron and steel
Iron alloys are metal systems, the main component of which is iron. Classification of alloys of iron: 1) alloys of iron with carbon (n
Heavy water
Heavy water - deuterium oxide D2O with oxygen of natural isotopic composition, colorless liquid without odor and taste. Heavy water was open
Chemical and physical properties.
In heavy water, the boiling point is 101.44 ° C, the melting point is 3.823 ° C. The D2O crystals have the same structure as the crystals of ordinary ice, the difference in size
Hydrochloric acid salts
Salts of hydrochloric acid or chlorides are chlorine compounds with all elements having a smaller value of electronegativity. Chlorides of metals
