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Saturday 10 January 2015

Science

Sodium metal is kept under ?
Kerosene (Like the other alkali metals, sodium metal is a soft, light-weight, silvery white, reactive metal. Owing to its extreme reactivity, it occurs in nature only combined in compounds, never as a pure elemental metal. Sodium metal floats on water and reacts with it violently, releasing heat and flammable hydrogen gas, and forming a solution of the strong base sodium hydroxide. 
Sodium's powdered form is highly explosive in water and is a poison when uncombined or combined with many other elements. This metal should be handled carefully at all times. Sodium must be stored either in an inert atmosphere, or under a liquid hydrocarbon such as mineral oil or kerosene.)

What is the Ingredients of Gun metal ?
Copper (80%), Tin(10%) , Zinc (2%), Gun metal is also known as red brass in United State is a type of Bronze

From which minerals is radium obtain ?
Pitchblende ( It is amorphous, black, pitchy form of the crystalline uranium oxide mineral uraninite; it is one of the primary mineral ores of uranium, containing 50-80 percent of the element. Three chemical elements were first discovered in pitchblende; uranium by the German chemist Martin Klaproth in 1789, and polonium and radium by the French scientists Pierre and Marie Curie in 1898.source - www.wikipedia.org

What is laughing gas ?
Nitrous oxide (N
2
O)

Actinides are the elements with the atomic numbers from ?
89 to 103 and is the third group of periodic table

The two elements that are frequently used in making transistors are? 
Silicon(Si) and Germanium(Ge) 

Carbon, Diamond, and Graphite are together called ?
Allotropes (Is a property of some chemical element to exists in two or more different forms.)

Tetraethyllead((CH3CH2)4Pb),TEL, is used as ?
petrol additive (It is a patented octane (Octane rating or octane number is a standard measure of the performance of an engine or aviation fuel) booster that allowed engine compression to be raised substantially, which in turn increased vehicle performance or fuel economy. Ethanol was already known as a widely available, inexpensive, low toxicity octane booster, but TEL was promoted because it was uniquely profitable to the patent holders. TEL was phased out starting in the U.S. in the mid-1970s because of its cumulative neurotoxicity and its damaging effect on catalytic converters (catalytic converter is a vehicle emissions control device that converts toxic pollutants in exhaust gas to less toxic pollutants by catalyzing a redox reaction (oxidation or reduction)). When present in fuel, TEL is also the main cause of spark plug fouling. TEL is still used as an additive in some grades of aviation gasoline, and in some developing countries.) source - www.wikipedia.org

Permanent hardness of water, due to sulphates and chlorides of the metal(calcium sulphate and/or magnesium sulphates; Magnesium chloride and/or calcium chloride), can be removed by adding
Zeolites but for hardness only caused by sulphates, we can use Sodium Carbonate, Na2CO3  (Hard water is water that has high mineral content (in contrast with "soft water").Hard water is formed when water percolates through deposits of calcium and magnesium-containing minerals such as limestone, chalk and dolomite.
Hard drinking water is generally not harmful to one's health, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. Permanent Hardness cannot be removed by boiling. Calcium and Magnesium sulphates in watr do not  precipitate out as temperature increases.Soap do not produce lather with hard water.source - www.wikipedia.org
Permutit or sodium aluminium silicate is a complex chemical compound, which occurs as a natural mineral called Zeolite. Permutit or zeolites are insoluble in water and have the property of exchanging ions present in them with the ions present in the solution.
Permutit or zeolites are packed in a suitable container and a slow stream of hard water is passed through this material. As a result, calcium and magnesium ions present in hard water are exchanged with sodium ions in the permutit (Na+Al-Silicate). The outgoing water contains sodium salts, which do not cause hardness.

Temporary hardness of water, due to bicarbonates of the metal(calcium bicarbonate and/or magnesium bicarbonate), can be removed by 

It can be removed by boiling or by the addition of lime (calcium hydroxide) Boiling promotes the formation of carbonate from the bicarbonate and precipitates calcium carbonate out of solution, leaving water that is softer upon cooling.

Which metal remains in liquid form under normal condition ?
Mercury (Hg, melting point is -38.83 degree Celsius)

Diamond is harder than Graphite because of ?
Because of Difference in crystalline structures(diamond is made up of carbon atoms,each is covalently bonded to four other carbon atoms(strong covalent bonds) ,forms a tetrahedral shape (crystal lattice structure))

Potassium nitrate(saltpetre)KNO₃, is used in ?
medicine(Major uses of potassium nitrate are in fertilizersrocket propellants and fireworks. It is one of the major constituents of gunpowder(blackpowder)(It is a mixture of sulphur, charcoal and potassium nitrate) and has been used since the Middle Ages as a food preservative)

Marsh gas is ?
Methane 

Soda water contains ?
Carbon dioxide (CO2 ; melting point is -78 °C , boiling point is -57 °C)

Non - stick utensils are coated with ?
Teflon (C2F4)n

Which gas is lighter than air ?

Ammonia 

Of the various purpose of carbon one form of carbon which   

is used in adsorption purpose is ?

Wood charcoal (Adsorption, the binding of molecules or particles to a surface, must be distinguished from absorption, the filling of pores in a solid.The most common industrial adsorbents are activated carbon, silica gel, and alumina, because they present enormous surface areas per unit weight. Activated carbon is produced by roasting organic material to decompose it to granules of carbon - coconut shell, wood, and bone are common sources. Silica gel is a matrix of hydrated silicon dioxide. Alumina is mined or precipitated aluminum oxide and hydroxide. Although activated carbon is a magnificent material for adsorption.)

Galvanised iron sheet have a coating of ?

Zinc (Galvanization is the process of applying a protective zinc coating to steel or iron in order to prevent it from rusting.)

The metal used in storage batteries are ?
Lead 

The chemical name of urea(CO(NH2)2) is ?
Carbamide 

The most malleable metal is ?

Gold 








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