Chemistry Quiz 6

Alizarin (C₁₄H₈O₄) is a natural dye. It is a red dye originally obtained from the root of the common madder plant, Rubia tinctorum, in which it occurs combined with the sugars xylose and glucose. In 1869, it became the first natural dye to be produced synthetically.

Glass is a supercooled liquid. When glass is made, the material (often containing silica) is quickly cooled from its liquid state but does not solidify when its temperature drops below its melting point. At this stage, the material is a supercooled liquid, an intermediate state between liquid and glass.

Freon is a non-combustible gas that is used as a refrigerant in air conditioning applications. It is Dichlorodifluoromethane (CCl₂F₂). Dichlorodifluoromethane is a colourless gas usually sold under the brand name Freon-12.

Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight, creating a brown haze above cities. The major chemical pollutants in Photochemical smog are NO and NO₂, VOCs, Ozone (O₃) and PAN (Peroxyacetyl Nitrate).

Curie point, also called Curie Temperature (T_C) is the temperature at which certain magnetic materials lose their magnetic properties.

Gypsum is a mineral and is hydrated calcium sulphate in chemical form. It slows down the hydration process of cement once it is mixed with water. It is mainly used for preventing the rapid setting of cement.

Tetraethyllead (TEL) is an antiknock compound with the formula Pb(C₂H₅)₄. An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs.

The amount of chlorine available in water after disinfection is called as residual chlorine. Typically chlorine doses to final treated waters are in the range 0.2–2.0 mg/l of free chlorine to give a residual of about 0.02–0.3 mg/l at the consumer's tap.

Magnesium is present in seawater in amounts of about 1300 ppm. The six most abundant ions of seawater are chloride (Cl⁻), sodium (Na⁺), sulphate (SO²₄⁻), magnesium (Mg²⁺), calcium (Ca²⁺), and potassium (K⁺). By weight, these ions make up about 99 percent of all sea salts.

Cadmium does not react with water to produce Hydrogen. The alkali metals (Li, Na, K, Rb, Cs, and Fr) are the most reactive metals in the periodic table - they all react vigorously or even explosively with cold water, resulting in the displacement of hydrogen.