2 Important compounds of alkaline earth metals. Carbonates.
Salts of sulfate, silicate and phosphate are also found in the Earth’s crust. Purple apatite (calcium phosphate) mineral 723025126 Gypsum statue 748413898Strontium, barium, radium are found in trace amount in nature. Strontium occurs as celestite (SrSO4) and strontianite (SrCO3), barium occurs as barytes (BaSO4) and witherite (BaCO3). All the isotopes of radium are radioactive. The isotope 226Ra is the most stable isotope with a 1600 year half life.
The radium element is a side product of the natural decay of 238U.
Most of the compounds of beryllium and some compounds of magnesium show a tendency to covalency, so they differ from other compounds in the group.
Halides.Except for beryllium halides, all other halides of alkaline earth metals are ionic in nature. Beryllium halides are essentially covalent and soluble in organic solvents. The tendency to form halide hydrates gradually decreases (for example,MgCl2×8H2O, CaCl2×6H2O, SrCl2×6H2O and BaCl2×2H2O) down the group. The fluorides are relatively less soluble than the chlorides owing to their high lattice energies.CarbonatesCarbonates of alkaline earth metals are insoluble in water and can be precipitated by addition of a sodium or ammonium carbonate solution to a solution of a soluble salt of these metals.
The solubilityof carbonates in water decreases as the atomic number of the metal ion increases. All the carbonates decompose on heating to give carbon dioxide and the oxide. Beryllium carbonate is unstable and can be kept only in the atmosphere of CO2.SulfatesThe sulphates of the alkaline earth metals are all white solids and stable to heat. BeSO4, and MgSO4are readily soluble in water; the solubility decreases from CaSO4 to BaSO4.
The greater hydration enthalpies of Be2+ and Mg2+ ions overcome the lattice enthalpy factor and therefore their sulfates are soluble in water.NitratesThe nitrates are made by dissolution of the carbonates in dilute nitric acid. Magnesium nitrate crystallises with six molecules of water, whereas barium nitrate crystallises as the anhydrous salt. This again shows a decreasing tendency to form hydrates with increasing size and decreasing hydrationenthalpy.
All of them decompose on heating to give the oxide like lithium nitrate: 2Me(NO3)2 ? 2MeO + 4NO2 + O2
Ca(OH)2(s) + CO2(g) ? CaCO3(s) + H2O(g)Calcium carbonate occurs naturally as marble, limestone, chalk and calcite. As mentioned above, it forms by evolving CO2 gas from Ca(OH)2 solution. Underground water containing CO2 dissolve some amount of CaCO3 and the equilibrium below is established. CaCO3(s) + CO2(g) + H2O(l) ? Ca(HCO3)2(aq)When such underground water reaches the earth’s surface, the pressure on it decreases. Because of the decrease in solubility of CO2 in water, the equilibrium reaction shifts to the left, that is, CaCO3 precipitate is formed. Formation of stalactites and stalagmites is a good example of this process.
Gypsum CaSO4×2H2O is a white substance which is used commercially for fabrication into wallboard. When gypsum is heated above 100°C, it loses 3/4 of its water of crystallization, forming the powdered substance CaSO4×0.5H2O, known as plaster of Paris.2CaSO4×2H2O ? 2CaSO4×0.5H2O + 3H2OBy mixing with water, the small crystals of plaster of Paris dissolve and then re-crystallize as long needles of CaSO4×2H2O. Calcium sulfate, CaSO4 is a constituent of cement. Additionally, it is used in decoration as plaster of Paris, and in dentistry to mold teeth.
Gypsum has been used indrywallplaster ingredientfertilizer and soil conditionersurgical splints, casting molds, modelingadding hardness to water used for homebrewing.a component of Portland cement used to prevent flash setting of concrete.Kazakhstan is rich in natural resources, and mining is quite important to the economy of Kazakhstan. Among the best-known deposits of phosphates are the Karatau Range, Mangystau and Aktobe region. The Zhambyl region belt is the gypsum producing area in the country. The Kostanay region is rich in minerals dolomite and asbestos in Zhitikara.
Karatau Ridge 743063965
The main pigment for the absorption of light in plants is chlorophyll which contains magnesium. About 99 % of body calcium is present in bones and teeth. It also plays important roles in neuromuscular function,interneuronal transmission, cell membrane integrity and blood coagulation.??? ??????? ???? ????? ??? ?????
Write ionic and net ionic equations for the following reactions:CaCO3 + H2SO4 ?BaCl2 + Na2CO3 ?3. Which of the following processes will likely result in a precipitation reaction?mixing a H3PO4 solution with a Ca(OH)2 solution.mixing a HF solution with a CaCl2 solution. mixing a K2SO4 solution with a Ba(OH)2 solution.4. Suggest one method by which you might separateCa2+ from Cu2+NH4+ from Ca2+5.
Calcium oxide used in cement industry: CaCO3 ? CaO + CO2Calculate the yearly release of carbon dioxide CO2 to atmosphere if the annual production of calcium oxide in the Kazakhstan is 1.25×108 kg.