Physicochemical properties of water

Here you will get physical and chemical properties of water

1. Presented by Miss Pratiksha Puranik M.Sc.(Zoology), B.Ed., MH-SET, Ph.D. pursuing

2. Contents Introduction Structure of the water molecule Physical properties Chemical properties Reference

3. What Is Water? Water is the chemical substance with chemical formula  H 2 O , one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. Biological process take place in water, which acts as important solvent and plays a role in determining the pathway taken by the reaction. Water is a key reactant in many reactions, usually in the form of H⁺ & OH⁻. Water is oxidized in photosynthesis to produce molecule oxygen, O₂ as part of the process that converts the suns energy into usable chemical form.

4. Cont………. Water is most abundant substance in living systems, making up 70% or more of the weight of organism. The first living organism doubtless arose in an aqueous environment, and the course of evolution has been shape by the properties of the aqueous medium in which life began. The physical and chemical properties of water, to which all aspects of cell structure and function are adapted.

5. Structure of Water Molecule

6. Physicochemical properties of water Water is a colourless and tasteless liquid The high electronegativity of oxygen relative to hydrogen results in the establishment of a permanent dipole in water molecules. The polar nature of water results in negative portions of the molecule being attracted to the positive portions of neighboring water molecules by a largely electrostatic interaction known as the hydrogen bond.

7. Conti….. Water is strongly hydrogen bonded, with each water molecule participating in four hydrogen bonds with its neighbors ; two in which it donates and two in which it accepts. Hydrogen bonds commonly form between water molecules and the polar functional groups of biomolecules, or between the polar functional group themselves. All the major components in cell (proteins, DNA and polysaccharides) are dissolved in water. Pure water has a low electrical conductivity.

8. Cont…… A high heat of vaporization, such that relatively more heat must be input to vaporize water compared to other substances of similar molecular mass. An ability to dissolve most polar compounds.

9. Chemical Properties of Water Amphoteric nature:- ability some chemical acts either acid or base. Universal solvent:- dissolves more substances than any other common liquid. Polarity:- water has positive and negative ends. Polar compounds are water loving (hydrophilic). Non polar compounds are water hating (hydrophobic).

10. Water is a neutral, polar molecule that has a slight tendency to ionize into H⁺ & OH⁻. However, the proton is never free & binds to a water molecule to forms H₃O⁺ (hydronium ion) The ionization of water is described as an equilibrium between the unionized water (reactant) and its ionized species products). H₂O H⁺ + OH⁻ Water acts as a Base & Acid.

11. Reference N. L. David., Michael M. Cox. Lehninger Principles of Biochemistry ,Vth Edition

12. Thank you