Chemistry Quiz 4

Combustion is a chemical process. It is a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame.

Tear gas is a chemical compound that causes temporary skin, respiratory, and eye irritation. Chloropicrin (CCl₃NO₂) is one of the constituents of tear gas. Chloropicrin has been used in chemical warfare and as tear gas.

The reason there is not much hydrogen in the atmosphere is because it is lighter than air, and so can easily escape the Earth's gravity.

The mixture of Propane (C₃H₈) and Butane (C₄H₁₀) gases is mainly stored as a liquid under pressure in LPG cylinder.

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.

Radioactive elements are made up of atoms whose nuclei are unstable and give off atomic radiation as part of a process of attaining stability. Uranium, Radium, Polonium, Thorium, etc are common radioactive elements. Zirconium is non-radioactive element.

Fibre-lass is used for making glass-reinforced plastic. Fiber-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass, carbon, aramid, or basalt.

All steel contains at least some amount of carbon. After all, steel is defined as an alloy of iron and carbon. By adding carbon to it, the metal becomes stronger and harder. The percentage of carbon in steel ranges from 0.1 to 2. Depending on the carbon percentage, steel is classified into mild steel (0.02–0.05%), medium-carbon steel (0.05–1%) and high-carbon steel (1–2%).

Seawater can be purified by the process of distillation. Distillation is a phase separation method whereby saline water is heated to produce water vapor, which is then condensed to produce fresh water.

The colour of the most popular emerald is pure deep green. Emerald is a gemstone and a variety of the mineral beryl (Be₃Al₂(SiO₃)₆) coloured green by trace amounts of chromium or sometimes vanadium.