Properties of water important for life

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Water is essential for life. It is the most abundant chemical and also the most abundant inorganic substance.

Main functions of water 

1. Water is the main component of the protoplasm (The  Living content of a cell that is surrounded by a plasma membrane)

2. Water is a reactant in man biochemical reactions e.g: Photosynthesis

3. Water is a good solvent. Therefore it is the medium for many biochemical reactions.

4. Water helps in maintaining turgidity in living organisms.

 In addition to these main functions

In plants water helps in :

1. Absorbing minerals and act as the medium of transport


2. Transporting organic food


3. Germinating seeds


4. Turgor movements  of stomata


5. Acting as a medium for fertilization


6. Medium for pollination


7.  Seed dispersal


8. Maintaining turgidity in herbaceous plants

In Animals water

1. Is the main component in body fluids


2.  Moistens the respiratory surfaces


3. Acts as a lubricant in joints


4. Cools the body surface by evaporation


5. Habitat for some organisms



Water has many important chemical and physical properties making it the main chemical found in living organisms.

chemical and physical properties of water

1. A liquid at room temperature- therefore water is the main medium of protoplasm


2. Polarity- water is a good solvent therefore


3. High surface tension-  small insects such as water skaters can live on the surface of water


4. High specific heat capacity-helps to maintain the body temperature without major fluctuations


5. High latent heat of vaporization-  cools body surfaces because a high heat is absorbed from body surfaces for evaporation


6. High latent heat of fusion- water doesn't freeze easily as a large amount of heat has to be dissipated from water to turn into ice


7. Anomalous expansion of water  when freezing- Due to this property density of water decreases when freezing. It makes ice float on water. Ice is a good insulator. theretofore liquid water remains at the bottom of water bodies without  freezing. Aquatic animals can survive in water dung winter season due to this.


8. Transparent- Water  is a transparent liquid. It allows penetration of light into deep water allowing the growth of aquatic plants and algae in a considerable depth


9. High adhesive and cohesive forces- transport of water in xylem is due to adhesive forces among water molecules and cohesive forces between water molecules and xylem capillary walls.

10. chemical property- water is a common reactant in biochemical reactions

Metals

Elements in the periodic table can be divided in to metals, non metals and metalloids having both metallic and non metallic characters.
All the transition elements and all the elements in the first two groups of the periodic table are among the metals found in the periodic table. Metals are mostly solids except for mercury (Hg) which is a liquid metal.

Metals can be identified by their metallic properties such as

•  having high melting points 
•  having high boiling points;
•  malleable
•  good conductors of heat 
•  good conductors of electricity

These properties of metals can be explained with the structure of the metals

Metals are making a giant structure with metallic ions (e.g : Cu 2+ ions in Cu, Na + ions in Na) bonded together tightly with each other with metallic bonds forming  a giant 3d structure. Delocalized free moving electrons are moving around the ion lattice.

High melting and boiling point of the metals are due to the strong metallic bonds found in metal structure due to the electrostatic force between positively charged metal ions and negatively charged free moving electrons.

Metals are malleable because the layers of metal ions can slide over each other without braking due to the free moving electrons acting like a glue.

Electrical and heat conductivity of metals is due to the free moving electrons passing the energy.

Properties of metals can be improved by making them in to alloys. alloys are a mixture of a metal with another element,
e.g. brass; stainless steel

Next about reactivity series