Chemistry Quiz 5

Fructose is the sweetest sugar. Sucrose is second sweetest followed by glucose and lactose.

Silver is not present in German silver. German Silver is an alloy of copper (60%), zinc (20%) and nickel (20%). It is named for its silver-white colour. It is used for making daily utensils and jewellery.

Aqua Regia (royal water) is used to dissolve noble metals. It is a mixture of nitric acid and hydrochloric acid in a ratio of 1:3. It can dissolve the noble metals gold and platinum, though not all metals.

Milk of magnesia is also known as magnesium hydroxide. It is an inorganic compound with the chemical formula Mg(OH)₂. It occurs in nature as the mineral brucite.

Oxyacetylene flame is commonly known as gas welding. It is a process which relies on combustion of oxygen and acetylene. When mixed together in correct proportions within a hand-held torch or blowpipe, a relatively hot flame is produced with a temperature of about 3200°C.

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.

Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and halons destroy the earth's protective ozone layer, which shields the earth from harmful ultraviolet rays generated from the sun. CFCs and HCFCs also warm the lower atmosphere of the earth, changing global climate.

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.

Sir Joseph John Thomson (1856-1940) was an English physicist who helped revolutionize the knowledge of atomic structure by his discovery of the electron (1897). Electron was discovered by him when he was studying the properties of the cathode rays.

Flint glass is optical glass that has relatively high refractive index and low Abbe number (high dispersion). For this reason, it is used for making the lens and prism.