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 space and the universe then this is a very narrow temperature range. ) 4. high heat of vaporisation Heat of vaporisation is the energy that is needed to change a given quantity of a substance into a gas. The strength of the hydrogen bonds between water molecules also means that it has a high heat of vaporisation. Heat of vaporisation” is the heat energy that is needed to change water from the liquid to the gas phase. Because the forces between molecules are strong, water has to be heated to 100 ? before it changes phase. At this temperature, the molecules have enough energy to break the intermolecular forces that hold the molecules together. The heat of vaporisation for water is 40,65 kJ•mol? 1. It is very important for life on earth that water does have a high heat of vaporisation. Can you imagine what a problem it would be if water’s heat of vaporisation was much lower?
Energy Efficient Building Windows Energy efficient windows have multiple layers of glass. The reason for this is because the more layers of glass you have the better it insulates the house. Three or four layers of glass are one of the best because you have more airspace in between layers. A smaller airspace doesn't insulate the building as well as a thicker airspace would.The thickest an airspace ...
All the water that makes up the cells in our bodies would evaporate and most of the water on earth would no longer be able to exist as a liquid! 5. Less dense solid phase Another unusual property of water is that its solid phase (ice) is less dense than its liquid phase. You can observe this if you put ice into a glass of water. The ice doesn’t sink to the bottom of the glass, but floats on top of the liquid. This phenomenon is also related to the hydrogen bonds between water molecules. While other materials contract when they solidify, water expands. The ability of ice to float as it solidifies is a very important factor in the environment.
If ice sank, then eventually all ponds, lakes, and even the oceans would freeze solid as soon as temperatures dropped below freezing, making life as we know it impossible on Earth. During summer, only the upper few metres of the ocean would thaw. Instead, when a deep body of water cools, the floating ice insulates the liquid water below, preventing it from freezing and allowing life to exist under the frozen surface. It should be clear now, that water is an amazing compound, and that without its unique properties, life on Earth would definitely not be possible.
... on Venus and Earth. Mars has permanent ice caps at both poles composed of water ice and solid carbon dioxide ('dry ice'). The ice caps exhibit a ... there was clearly some sort of fluid on the surface. Liquid water is the obvious fluid but other possibilities exist. There ... The Viking ladders performed experiments to determine the existence of life on Mars. The results were somewhat ambiguous but most ...