Railway Science (Chemistry-Miscellaneous)

Natural fibres are obtained from plants, animals or mineral sources converted into paper and woven, Examples - Cotton, Silk, Wool. Wool (keratin protein) primarily comes from sheep. Silk is a protein fibre made by silkworms and is the only natural fibre. Sericulture (Cultivation of silkworms).

A lit candle needs to draw oxygen from the air in order to continue burning, but when it is covered with a glass jar oxygen decreases and it gets filled with carbon dioxide and then the candle flame will extinguish. Oxygen is essential for burning.

The chemical formula for ammonia is NH₃ . The atomic mass of nitrogen is 14.0067 amu, and the atomic mass of hydrogen is 1.00794 amu. Most common uses of ammonia include - Fertilizer, Refrigerant, Cleaning agent, In the production of plastics, explosives and pharmaceuticals. Atomic mass unit (amu) - A unit for expressing masses of atoms, molecules, or subatomic particles.

Cysteine - It is a non-essential amino acid because it can be synthesized by the human body. It plays a vital role in the structure and function of proteins. Sulfur-containing amino acids : Methionine - Essential amino acid that contains sulfur. It is involved in protein synthesis.
Histidine - Basic amino acid and plays a crucial role in enzyme catalysis and protein function. Serine - Nonessential amino acid that is important for the synthesis of proteins and various other biomolecules. Tryptophan - An aromatic amino acid and is essential for protein synthesis.

Rayon - A synthetic fiber, made from natural sources of regenerated cellulose (such as wood) and related agricultural products. Examples (Man made fiber) - Nylon, Polyester, Acrylic, Aramid. Silk - A natural fiber produced by silkworms. Linen is derived from the flax plant. Jute is a natural fiber derived from the jute plant.

Acrylic is a transparent plastic material with outstanding strength, stiffness, and optical clarity. Nylon is a generic designation for a family of synthetic polymers composed of polyamides. Rayon is a synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products.

Cobalt therapy is the medical use of gamma rays from the radioisotope cobalt-60 to treat conditions such as cancer. Uranium isotopes - Such as uranium-235 (U-235), are primarily used in nuclear reactors for generating electricity. Copper - Used in industry and medicine. Iodine-131 (I-131) - An isotope of iodine, is used to treat thyroid cancer.

Osmium (Os, atomic number - 76). It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores.
Uses - To produce very hard alloys for fountain pen tips, instrument pivots, needles and electrical contacts. Other elements and their atomic number - Platinum (Pt, 78), Copper (Cu, 29).

It is a mixture of nitric acid (HNO₃) and hydrochloric acid (HCl) in the ratio of 1 : 3 . It is a red or yellowish liquid. Aerosol - A suspension of particles or droplets in the air.
Nessler's reagent (K₂HgI₄) is an aqueous solution of potassium iodide, mercuric chloride, and potassium hydroxide, Used to detect ammonia. Liquor Ammonia (NH₄OH) - It is used to remove oil, grease etc. stains from clothes.

Pepper - It is used for flavoring and does not have preservative properties. Salt, sodium benzoate, and sodium metabisulphite are used as preservatives in pickling to prevent spoilage and inhibit the growth of bacteria and other microorganisms.
Sodium benzoate is a common preservative in acid or acidified foods such as fruit juices, syrups, jams and jellies, sauerkraut, pickles, fruit cocktails, etc.