INORGANIC COMPOUNDS AND SOLUTIONS

INORGANIC COMPOUNDS AND SOLUTIONS

COMPOUNDS IN OUR BODY 

1. ORGANIC
2. INORGANIC

INORGANIC COMPOUNDS

         -Usually lack carbon.

         - are structurally simple.

         - include water
                         many salts
                         acids
                         bases

          - may have either ionic or covalent bonds.

  Water- forms 55-60% of adults total body mass.

  Other inorganic compounds form 1-2 % 


Inorganic compounds with carbon

          Carbon dioxide  -  CO2
          Bicarbonate ion -  HCO3-
          Carbonic acid    -  H2CO3
       

WATER

Most important and abundant inorganic compound in all living systems.

Most important property of Water- 

   POLARITY
         - the uneven sharing of valence electrons that confers a partial negative charge near the oxygen atom and  2 partial positive charges near the 2  hydrogen atoms in a water molecule.

 1. This makes water an excellent solvent for other ionic or polar substances.

2. Gives water molecules cohesion.

3. Allows water to resist temperature changes.


1. WATER AS A SOLVENT

SOLVENT

  A substance that dissolves a solute or another substance in a solution.

eg. 

   Sweat  -   dilute solution of water + small amount of salts 
  (solution)                   (solvent)               (solute)


The versatility of water as a solvent for ionized or polar substances

   is due to 
         its polar covalent bond 
             and
         its bent shape
            which allows each water molecule to interact with several neighbouring ions or molecules.


HYDROPHILIC AND HYDROPHOBIC SOLUTES

a. HYDROPHILIC SOLUTES

  hydro- = water
- philic= loving

  - solutes that are charged or 
                              contain polar covalent bond.

  - they dissolve easily in water.

eg.
  sugar
  salt

b. HYDROPHOBIC SOLUTES

- phobic = fearing.

  -Molecules that contain mainly non polar covalent bond

  - not very water soluble.

eg.

   animal fats
   vegetable oils.


DISSOLVING POWER OF WATER

eg. NaCl placed in water

The electronegative oxygen atom in water molecules attracts the sodium ions Na+ and 
        the electropositive hydrogen atoms in water molecules attracts the chlorine Cl- ions.

Soon water molecules surrounds and separate Na + and Cl- ions from each other at the surface of the crystal

-  breaking the ionic bonds that held NaCl together.

The water molecules surrounding the ions also lessens the chance that Na+ and Cl- will come together 
   and reform an ionic bond.

in body

1. Water is an ideal medium for metabolic reactions.

    Water enables dissolved reactants to collide 
                                  and from products.

2. Also dissolves waste products 
      which allows them to be flushed out of the body in the urine.



2. WATER IN CHEMICAL REACTIONS

a. Serves as the medium for most chemical reactions in the body.

b. Participates as a reactant or product in certain reactions


HYDROLYSIS

- lysis= to loosen or break apart

  Decomposition reaction that break down large molecules into smaller molecules by addition of water molecules.

  - enable dietary nutrients to be absorbed into the body.

eg.  During digestion , decomposition reactions  break down large nutrient molecules into smaller molecules by addition of water molecules.

DEHYDRATION- SYNTHESIS REACTION

de= from, down or out

When 2 smaller molecules join to form a large molecule, a water molecule is one of the product formed.

     Such reactions occur during synthesis of proteins.


3.  THERMAL PROPERTIES OF WATER

Water is said to have a high heat capacity

      -Water can absorb or release a relatively large amount of heat with only a modest change in its own temperature.

    -the reason for this property  
                         - is the large number of Hydrogen bonds in water.

As water absorbs heat energy , 
   some of the energy is used to break hydrogen bonds
   
   Less energy is then left over to increase the motion of water molecules
        - which would increase the waters temperature

The high heat capacity of water is used in 
a. Automobile radiators

    it cools the engine by absorbing heat without its own temperature rising to an unacceptably high level.

b. In body

      it lessens the impact of environmental temperature changes 

    - helping to maintain homeostasis of body temperature

HEAT OF VAPORIZATION

Water requires a large amount of heat to change from liquid to gas.

Its heat of vaporization is high.

eg.  As water evaporates from the surface of the skin, it removes a large quantity of heat 

        - providing a cooling mechanism.

4. WATER AS A LUBRICANT

Water is a major component of mucus and other lubricating fluids throughout the body.

Lubrication is especially necessary in 

a.In the chest - pleural and pericardial cavities.

b. Abdomen - peritoneal cavity

                         where internal organs touch and slide over one another.

c. At joints- where bones, ligaments and tendons rib against one another.

d. Inside gastro-intestinal tract- mucus and other watery secretions moisten foods

          - which aids their smooth passage through digestive system.

SOLUTIONS, COLLOIDS AND SUSPENSIONS

MIXTURE

           -  Is a combination of elements or compounds.

            -  that are physically blended together

            -but not bound by chemical bonds

eg.  The air we breathe is a mixture of gases that include nitrogen, oxygen , argon and carbon dioxide.

3 COMMON LIQUID MIXTURES

1. SOLUTIONS

2. COLLOIDS

3. SUSPENSIONS

SOLUTE

Once mixed together , solutes in a solution remain evenly dispersed among the solvent molecules.

       -because the solute particles in a solution are very small., 

       - a solution looks clear and transparent.

COLLOID

A colloid differs from a solution mainly because of the size of its particles.

The solute particles in a colloid are large enough to scatter light

 So colloids usually appear translucent or opaque.

eg. Milk

Milk is a liquid colloid

               both a colloid and a solution.

    - the large milk proteins make it a colloid.

     - where as

                  calcium salts

                   milk sugar (lactose)

                   ions

                           and 

                   other particles are in the solution.

Solutes in both solutions and colloids do not settle out and accumulate on the bottom of the container.

SUSPENSION

The suspended material may mix with the liquid  or suspending medium for sometime.

but eventually it will settle out.

eg. blood

When freshly drawn from the body , blood has an even reddish colour.

  After blood sits for a while in a test tube, RBC settle out of suspension 

         and drift to the bottom of theh tube.

Blood plasma

    the upper layer

            the liquid portion of the blood

     

      - appears pale yellow

       -  is both a solution 

                          of ions and other small solutes.

                                  AND

       -  a colloid

                   due to the presence of larger plasma proteins.

CONCENTRATION OF A SOLUTION

Expressed by

a. Mass per volume percentage

                  number of grams of a substance per 100 ml of a solution.

             - gives the relative mass of a solute found in a given volume of solution.

eg.

To make a 10 % NaCl solution

         take 10 gram of NaCl and add enough water  to make a total of 100 ml of solution.

b. in units of moles per liter (mol/L) 

              -Molarity- 1 mole of a solute in 1 L of solution.

 which relate to the total number of molecules in a given volume  of solution.

To make 1 molar solution of NaCl,

                 dissolve 1 mole of NaCl (58.44g)  in enough water to make a total of 1 Liter of solution.

MOLE

     is the amount of any substance that has a mass in grams equal to the sum of the atomic masses of all its atoms.

eg.

1 mole of the element sodium    = 22. 99 g

              atomic mass of sodium = 22. 99 g

1 mole of the element chlorine    = 35.45 g

            atomic mass of   chlorine = 35.45 g

1 mole of the salt NaCl                = 58.44 g

AVOGADRO'S NUMBER

       = 6.023X×10²³

^{A mole of anything has} 6.023X×10^{23 particles.}