Water molecules are polar

Because hydrogen atoms carry molecular negative charges, while oxygen atoms carry molecular positive charges. So water molecules have negative and positive poles.

Water has unique properties

Because of its polarity and hydrogen bonds between its molecules.

4- Water is regarded as "the general solvent".

Because so many substances dissolve in it due to the polarity of its molecules

Being water a polar solvent is very important to living organisms.

Because all the essential substances for living organisms (vitamin, salts, amine acids, gases, glucose) transport inside their bodies in the form of solutes dissolved in water, and these substances take part in metabolism reactions inside cells.

Water has the ability to ionize many molecules.

Because of the polarity of water molecules.

The ability of water to ionize many molecules is so important to living organisms.

Because it is essential for the occurrence of some chemical reactions inside living organisms.

Water has high specific heat.

Due to the hydrogen bonds between its molecules.

High specific heat of water is important to us.

Because:-

1- It helps living organisms have constant temperature which is essential for the vital processes occurring within their bodies, as cells contain lots of water to keep their temp. constant.

2- It provides living organisms with temperatures suitable for life on earth.

Waters of oceans absorb great amount of sunrays in the morning, and spreads them in atmosphere at night.

To keep the temperature of earth suitable for living organisms.

Water has low viscosity and high surface tension

Due to the hydrogen bonds between its molecules.

The low viscosity and high surface tension of water are important to us.

Because They work on the cohesion of cell substances and slowing down losing water in plants' leaves

13- Some insects can walk on water.

Due to the cohesion of the molecules on water surface, as water has high surface tension.

14- Water expands and its density decreases when its temperature becomes less than 4◦C

Due to the hydrogen bonds between its molecules.

15- Water expansion at temp. less than 4◦C is important to living organisms.

Because it enables living organisms to live in oceans and seas, as only the surface of water freezes (which works as an insulator to prevent the rest of water from freezing)

Дата добавления: 2015-11-16