Chemistry MCQs

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An endothermic process is any process which requires or absorbs energy from its surroundings, usually in the form of heat. It may be a chemical process, such as dissolving ammonium nitrate in water, or a physical process, such as the melting of ice cubes.

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Cryollite is an ore of Aluminium. The ore is first converted into pure aluminium oxide by the Bayer Process, and this is then electrolysed in solution in molten cryolite – another aluminium compound.

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Nickel allergy is a common cause of allergic contact dermatitis — an itchy rash that appears where your skin touches a usually harmless substance. Nickel allergy is often associated with earrings and other jewelry. But nickel can be found in many everyday items, such as coins, zippers, cellphones and eyeglass frames.

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Stainless steel is an alloy of Iron with a minimum of 10.5% Chromium. Chromium produces a thin layer of oxide on the surface of the steel known as the passive layer. This prevents any further corrosion of the surface. Increasing the amount of Chromium gives an increased resistance to corrosion.

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A pearl is largely made of calcium carbonate, CaCO3, and that compound occurs mostly as platelets having the structure of a naturally-occurring mineral called aragonite.

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Fat has more than twice as many calories per gram as carbohydrates and proteins. A gram of fat has about 9 calories, while a gram of carbohydrate or protein has about 4 calories.

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Fixation is commonly achieved by treating the film or paper with a solution of thiosulfate salt. Popular salts are sodium thiosulfate and ammonium thiosulfate. These are commonly used in modern rapid fixer formulae.

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Ethylene glycol is a chemical commonly used in many commercial and industrial applications including antifreeze and coolant. Ethylene glycol helps keep your car’s engine from freezing in the winter and acts as a coolant to reduce overheating in the summer. Ethylene glycol (antifreeze) is used in the cooling of a car radiator during the winter because it has a much lower freezing point than water. Its role in an automobile is to absorb heat from the engine.

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Dmitri Mendeleyev (1834 – 1907) was a Russian chemist who came up with the first periodic table of the elements which he published in 1865. He was able to predict the discovery of many more elements using the table. He arranged the elements by atomic weights and also proposed that elements, if arranged according to their atomic weight, exhibit an apparent periodicity of properties.

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Like many other things, milk contains bacteria, Milk also naturally contains a kind of sugar known as “lactose.” The bacteria that live in milk get energy from this special sugar and use it to reproduce to make even more bacteria. When the bacteria use the lactose sugars to reproduce, they change it from “lactose sugar” into “lactic acid,” which tastes sour.