Surface tension of water

Surfacetension of water

Hydrogenis the first element in the periodic table. It is an element inperiod one since it has only one energy level and in group 1 toosince its last, and only energy level contains only one electron.Hydrogen is an extremely positive atom and therefore combines withhighly negative atoms to form hydrogen bond. Two hydrogen atoms canjoin to form hydrogen gas which contains two molecules of hydrogen.According to IUPAC journal of pure and applied chemistry, hydrogenbond is the electrostatic attraction between polar molecules thatoccurs when hydrogen atom combines with a highly electronegative atomsuch as oxygen, fluorine or nitrogen. Hydrogen bond should howevernot be confused with a covalent bond since hydrogen is not a realbond but rather a particular strong dipole-dipole attraction (Gilliand Gilli).

Thesimplest example of hydrogen bond is perhaps found in watermolecules. Water is a combination of two atoms of hydrogen and oneatom of oxygen. The type of bonding between atoms is called theintermolecular hydrogen bonding. The intermolecular hydrogen bondingin water is responsible for the high melting point, boiling point andhigher surface tension of water compared to other hydrides that lackHydrogen bond. Two water molecules can form a hydrogen bond to formwater dimmer. When more molecules are present in the case of liquidwater, more bonding is possible since oxygen has two lone electrons. The lone electron combines with oxygen to form hydrogen bond.Therefore in presence of more oxygen atoms, there are more hydrogenbonds. Theses hydrogen bonds form a stable layer on the water surfaceknown as surface tension. Surface tension is the ability of anyliquid substance such as water resist from external forces(Maréchal).

Thestrength of the water surface is however weaker than some objects andat the same time stronger than others. The reason some objects suchas paper floats on water is because of the high surface tensioncaused by strong hydrogen bonds. Other floaters are lighter, and theyare however unable to break the surface tension of water. Sharpobjects such as needle and razor blade when horizontally placed onwater, the surface tension of water suspends them on top of the watersurface. However, these objects tend to oppose the surface tension ofwater when vertically places on the water surface. The sharp endbreaks the surface tension allowing these objects to sink deep inwater. However, it is clear that sharp objects can break the hydrogenbond. However, there are objects that are denser that than the watersurface thus when placed on the water surface, thy automaticallybreak the surface tension of water and sinks wholly (Ehrlich,LaBelle and Vitiello).

Thehydrogen bonding does not only explain the surface tension of water,but also reasons why water has a higher boiling point. High boilingpoint is due to the large amount of heat needed to break thesehydrogen bonds. More so the high melting of point of water is due tothe strength of hydrogen bond. It requires a lot of heat to splitthese hydrogen bonds thus melting the solid water. Hydrogen bondingalso addresses the issue of high water solubility of compounds suchas ammonia.

References

Gilli,Gastone, and Paola Gilli. TheNature Of The Hydrogen Bond.Oxford: Oxford University Press, 2009. Print

Maréchal,Yves. TheHydrogen Bond And The Water Molecule.Amsterdam: Elsevier, 2007. Print.

Ehrlich,Ken, Brandon LaBelle, and Stephen Vitiello. SurfaceTension.[Los Angeles]: Errant Bodies Press in collaboration with Ground FaultRecordings, Downey, CA, 2003. Print.