Ms J Denny
Why the specific properties of water make life in earth possible In many ways, water behaves very differently from other compounds. These properties are directly related to the microscopic structure of water, and more specifically to the shape of the molecule and its polar nature, and to the intermolecular forces that hold water molecules together. 1.
Specific heat is the amount of heat energy that is needed to increase the temperature of a unit mass of a substance by one degree. Water has a high specific heat, meaning that a lot of energy must be absorbed by water before its temperature changes. You have probably observed this phenomenon if you have boiled water in a pot on the stove. The metal of the pot heats up very quickly, and can burn your fingers if you touch it, while the water may take several minutes before its temperature increases even slightly. How can we explain this in terms of hydrogen bonding? Remember that increasing the temperature of a substance means that its particles will move more quickly. However, before they can move faster, the intermolecular forces between them must be disrupted. In the case of water, these forces are strong hydrogen bonds, and so a lot of energy is needed just to break these, before the particles can start moving further apart. 2.
Absorption of infra-red radiation
Water is able to absorb infra-red radiation (heat) from the sun. As a result of this, the oceans and other water bodies act as heat reservoirs, and are able to help moderate the Earth's climate. 3.
Melting point and boiling point
The melting point of water is 0 ℃ and its boiling point is 100 ℃ (at standard pressure or 0,987 atm). This large difference between the melting and boiling point is very important because it means that water can exist as a liquid over a large range of temperatures. (This temperature range is only large in the world around us, if we look at...
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