write the physical properties of water that influence proliferation and maintenance of life.(90-100words). BRAINEAST QUESTION.
Answers
We live on a planet that is dominated by water. More than 70% of the Earth's surface is covered with this simple molecule. Scientists estimate that the hydrosphere contains about 1.36 billion cubic kilometers of this substance mostly in the form of a liquid (water) that occupies topographic depressions on the Earth. The second most common form of the water molecule on our planet is ice. If all our planet's ice melted, sea-level would rise by about 70 meters.
Water is also essential for life. Water is the major constituent of almost all life forms. Most animals and plants contain more than 60% water by volume. Without water life would probably never have developed on our planet.
Water has a very simple atomic structure. This structure consists of two hydrogen atoms bonded to one oxygen atom (Figure 8a-1). The nature of the atomic structure of water causes its molecules to have unique electrochemical properties. The hydrogen side of the water molecule has a slight positive charge (see Figure 8a-1). On the other side of the molecule a negative charge exists. This molecular polarity causes water to be a powerful solvent and is responsible for its strong surface tension (for more information on these two properties see the discussion below).
Figure 8a-1: The atomic structure of a water (or dihydrogen monoxide) molecule consists of two hydrogen (H) atoms joined to one oxygen (O) atom. The unique way in which the hydrogen atoms are attached to the oxygen atom causes one side of the molecule to have a negative charge and the area in the opposite direction to have a positive charge. The resulting polarity of charge causes molecules of water to be attracted to each other forming strong molecular bonds.
When the water molecule makes a physical phase change its molecules arrange themselves in distinctly different patterns (Figure 8a-2). The molecular arrangement taken by ice (the solid form of the water molecule) leads to an increase in volume and a decrease in density. Expansion of the water molecule at freezing allows ice to float on top of liquid water.
Figure 8a-2: The three diagrams above illustrate the distinct arrangement patterns of water molecules as they change their physical state from ice to water to gas. Frozen water molecules arrange themselves in a particular highly organized rigid geometric pattern that causes the mass of water to expand and to decrease in density. The diagram above shows a slice through a mass of ice that is one molecule wide. In the liquid phase, water molecules arrange themselves into small groups of joined particles. The fact that these arrangements are small allows liquid water to move and flow. Water molecules in the form of a gas are highly charged with energy. This high energy state causes the molecules to be always moving reducing the likelihood of bonds between individual molecules from forming.