Chemistry Quiz 4

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.

Ammonal is an explosive made up of aluminium powder and ammonium nitrate. The mixture is often referred to as Tannerite, which is a brand of ammonal.

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.

Silver bromide (AgBr) is used for making a film for photography. It is used in photography as a component of an emulsion that helps develop a photographic image. Silver bromide is sensitive to light, and when suspended in gelatin, silver bromide's grains create a photographic emulsion. When exposed to light, silver bromide decomposes and as a result, it preserves a photographic image.

Graphite is used in pencil lead because it is soft and leaves an impression on the paper and cleans easily between the layers. It has layered structure layers are held by van der Waal forces.

The four common radioactive elements are Uranium, Radium, Polonium, Thorium, etc. Radioactive elements are made up of atoms whose nuclei are unstable and give off atomic radiation as part of a process of attaining stability. The emission of radiation transforms radioactive atoms into another chemical element, which may be stable or maybe radioactive such that it undergoes further decay.

Matter is any substance that has mass and takes up space by having volume. Pure matter can be either Elements or Compounds. Carbon dioxide is a pure matter. Examples of pure matter include carbon, oxygen, iron, table salt and water. Air is a homogeneous mixture. Brass and Steel are alloys, therefore it is a mixture.

The gas used for filling weather balloons is helium. Hydrogen is lighter than air and can be used in filling air balloons but due to its highly inflammable nature, it is not used in air balloons.

Phosphorus is used in making smoke bombs. White phosphorus burns with a brilliant yellow flame while producing ample amounts of white smoke which is phosphorus pentoxide (P₄O₁₀).

Anthracite is the highest grade and best equality coal. It is a hard, very low content of volatile compact variety of coal that has a high luster. It has the highest carbon content (92.1% to 98%), the fewest impurities, and the highest calorific content.