2a2 Science Blog: LSS Science Online Lesson Done by Aloysius Chan

Formaldehyde

Formaldehyde is a compound which is made up the elements, Carbon, Hydrogen and Oxygen. Its chemical formula is CH₂O. It is a colourless gas that has a pungent odour and is very poisonous. It is used in the cigarettes and also to preserve the dead bodies. It can cause cancer, respiratory, skin and gastrointestinal problems.

Constituent elements:

Carbon is a harmless element that is non-metallic and tetravalent and thus, it makes four electrons available to form covalent chemical bonds. All forms of carbon are highly stable, requiring high temperature to react even with oxygen. This is so as its electronic configuration is 2.4 and thus, it is quite unlikely to become unstable as it needs to either gain 4 more electrons or lose 4 electrons. Unlike elements like Fluorine, which has an electronic configuration of 2.7, and thus, it is highly unstable.

Hydrogen is another harmless element that has an atomic number of 1. Although it is highly flammable, it is very abundant in the universe, but not as abundant on Earth. Thus, it is relatively safe on Earth. Stars also contain hydrogen. Hydrogen is also used in water, what we drink in everyday life. Hydrogen gas was also first artificially produced in the early 16th century, via the mixing of metals with strong acids. At standard temperature and pressure, hydrogen is a colourless, odourless, non-metallic, tasteless, highly combustible diatomic gas with the molecular formula H₂.

Oxygen is also a harmless element and at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colourless, odourless, tasteless diatomic gas with the formula O₂ an essential element in life. Oxygen is a member of the chalcogen group on the periodic table, and is a highly reactive non-metallic element that readily forms compounds with almost all other elements (eg. Carbon Dioxide(CO2), Water (H2O)). By mass, oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earth's crust, making up almost half of the crust's mass.

Thanks,

Aloysius