Chemistry Quiz 5

Earth's greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapor (which all occur naturally), and fluorinated gases (which are synthetic).

Cement is formed by strongly heating a mixture of limestone and clay. Cement manufacturing is a complex process that begins with mining and then grinding raw materials that include limestone and clay, to a fine powder, called raw meal, which is then heated to a sintering temperature as high as 1450 °C in a cement kiln.

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 atom bomb is discovered by German chemist Otto Hahn. He is referred to as the father of nuclear chemistry and godfather of nuclear fission. Hahn and Lise Meitner discovered radioactive isotopes of radium, thorium, protactinium and uranium.

Cobalt oxide (Co₃O₄) imparts a deep blue colour to the glass. Before the glass can cool and solidify, cobalt can be added to the mixture to give the glass a deep blue colour.

Tincture of iodine (weak iodine solution) is an antiseptic. It is usually 2 to 7 percent elemental iodine, along with potassium iodide or sodium iodide, dissolved in a mixture of ethanol (Ethyl Alcohol) and water. Tincture solutions are characterized by the presence of alcohol.

Carbon dioxide (CO₂) gas is used in a fire extinguisher because it displaces or reduces the amount of oxygen in the atmosphere around the fire. CO₂ is suitable for both electrical and flammable liquid fire types.

High octane fuel contains high content of lead. If tetraethyl lead, Pb(CH₂CH₃)₄, was put into petrol, particles of lead and lead oxide PbO are formed on combustion. This helps the petrol to burn more slowly and smoothly, preventing knocking and giving higher Octane ratings.

Water hyacinth (Eichhornia crassipes) is used for cleansing polluted water bodies owing to its remarkable capacity of absorbing pollutants.

Chlorophyll is the natural compound present in green plants that gives them their colour. It consists of a central magnesium atom surrounded by a nitrogen-containing structure called a porphyrin ring; attached to the ring is a long carbon-hydrogen side chain, known as a phytol chain. Calcium is not a component of chlorophyll.