Chemistry Podcast

Sunday, 9 August 2015

12 Class Chapter 16 - Chemistry In Everyday Life

Chemistry In Everyday Life


                    Drugs that binds to the receptor site and inhibits its natural function is known as antagonists.


               Drugs that mimic the natural messenger by switching on the receptor is called as agonists.


               Its example is Metal Hydroxide.


                        Its example is Terfinadine, Cimetidine. Histamine stimulates the secretion of pepsin and HCl in stomach.

Neurological Active Drugs


                       Chemical compound used for the treatment of stress or severe mental diseases. These relive anxiety, stress, irritability, depression, tension by inducing a sense of well being. Examples- Iproniazid,  Equanil, Barbiturates are hypnotic that is sleep producing agents.


                 These drugs reduce or abolish pain without causing mental confusion, paralysis and some other disturbances. Example- Asprin, Analgin, Paracitamol.
Narcotics Analgesics are Morphine, Heroine.


                   These drugs inhibit the growth of microorganisms or kill the microorganisms. Example- Penicillin, Tetracycline, Imipenam, Meropenam, Ampicillin, Chloramphinicol.


                  Furacine, Soframycine, Dettol (Chloroxylenol + Terpinol), Bithional.


                     Apply to lifeless objects. Chlorine(0.2 to 0.4 ppm), SO2 in low concentration. 
NOTE: "0.2% solution of phenol is antiseptic while its 1% solution is disinfectant."

Antifertility Drugs

                                Drug used to control population. Example- Norethindrone, Novestrol.

Food Preservative

                                Prevent spoilage of food due to microbial growth. Example- Sodium Benzoate, table salt.

Gold Number

                      It is the calculation of the weight of the protective colloid in milligram to be added to 10 ml of gold solution to prevent its coagulation when 1 ml of 10% of NaCl solution is added to it rapidly.
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Monday, 27 July 2015

10 Class- Chemical Reactions and Equations

Chemical Reactions and Equations

  • ·       Every chemical change is a chemical reaction.
  • ·       General observation to identify whether a chemical reaction take place or not-
1.    Change in state.
2.    Change in color.
3.    Evolution of gas.
4.    Change in temperature.

Chemical Equations:

Any equation which describes the change of reactants to products is called chemical reaction.
Reactant1+Reactant2+…………--->   Product1+Product2+………

In chemical equations reactants are placed on left hand side and products are placed on right hand side and arrow sign is placed between them. Direction of arrow shows the direction of reaction.
Example: chemical equations in words.
Magnesium + Oxygen {Reactants} .------->  Magnesium-Oxide {Product}

Writing a Chemical Equation by using Chemical Formula:

In it we use symbols instead of words to write a chemical equation.
Example: Mg + O2 .-----> MgO

     1.    Unbalanced Chemical Equation:

Equation in which number of atoms on reactant side is not equal to number of atoms on product side, means mass is not same on both sides.
         Example: Mg + O2 -----> MgO
                          Fe +  H2-----> Fe3O4 + H2

     2.    Balanced Chemical Equation:

Equation in which number of atoms on reactant side is equal to number of atoms on product side, means mass is same on both sides.
         Example: 2Mg + O2 ----> 2MgO
                          3Fe + 4H2O -----> Fe3O4 + 4H2

Writing Symbols of Physical State:

                                                          Reactants and products are written with their physical state to make equation more informative.
Physical State
Example: 3Fe (s) + 4H2O (g) -----> Fe3O4 (s) + 4H2 (g)
·       Example of reactions with reaction condition like pressure, temperature, catalyst etc.
10 classes science chemistry note

Types of Chemical Reactions:

                                                Chemical reactions are reactions which involve making and breaking of bonds between atom to yield new substances.

    1.    Combination Reaction:

These are the reactions in which one single product is formed from two or more reactants.
Example: i. Formation of Calcium Hydroxide.
CaO (s)(quick lime) + H2O (l) -------> Ca(OH)2 (aq)(slaked lime)
ii. Burning of Coal.
C (s) + O2 (g) ------> CO2 (g)
iii. Formation of Water.
2H2 (g) + O2 (g) ------> 2H2O (l)

    2.    Displacement Reaction:

These are the reactions in which highly reactive metal displaces less reactive metal from their solution.
Example: i. Fe (s) + CuSO4 (aq)(copper sulphate) -------> FeSO4 (aq)(iron sulphate) + Cu (s)
 ii. Zn (s) + CuSO4 (aq)(copper sulphate) -------> ZnSO4 (aq)(zinc sulphate) + Cu (s)
iii. Pb (s) + CuCl2 (aq)(copper chloride) -------> PbCl2 (aq)(lead chloride) + Cu (s)

    3.    Double Displacement Reaction:

These are the reactions in which exchange of ions between reactants occur.
Example: Na­2SO4 (aq)(sodium sulphate) + BaCl2 (aq)(barium chloride) -------> BaSO4 (s)(barium sulphate) + 2NaCl (aq)(sodium chloride)

    4.    Oxidation and Reduction Reaction:

1.1.        Oxidation:

These are the reactions in which a substance loses hydrogen or gain oxygen.
          Example: 2Cu + O2 + Heat ----------> 2CuO

1.2.        Reduction:

These are the reactions in which a substance gain hydrogen or loses oxygen.
          Example: CuO + H2 + Heat ----------> Cu + H2O

1.3.        Redox Reaction:

These are the reactions in which one reactant gets reduced while other reactant gets oxidized. This type of reaction is also known as Oxidation-Reduction Reaction or Redox Reaction.
i.                   CuO + H2 + Heat ---------> Cu + H2O
In above reaction-
                   H2 ---------> H2O (oxidation)

                   CuO --------> Cu (reduction)

ii.                ZnO + C --------->  Zn + CO
iii.             MnO2 + 4HCl --------> MnCl2 + 2H2O + Cl2

Observable Effect of Oxidation Reduction in Everyday Life:

1.    Corrosion:

   Attack on metals by moisture, acids, oxygen etc., which corrode metals is called corrosion.

Example: Rusting of Iron, Black coating on Silver, Green coating on Copper.

2.    Rancidity:

   Change in taste and smell of food material prepared by using fat or oil, because fat or oil get oxidized and become rancid.

Endothermic Reaction:

                                      These are the reactions in which heat is absorbed during reaction.

Example: NH4Cl (s) + H2O (l) + Heat --------> NH4Cl (aq)

Exothermic Reaction:

                                      These are the reactions in which heat is evolved during reaction.

Example: CH4 (g) + 2O2 (g) --------> CO2 (g) + 2H2O (g) + Heat

Precipitation Reaction:

                                      These are the reactions in which insoluble substance called precipitate is obtained when reaction completes, is known as precipitation reaction.

Example: Na2SO4 (aq) + BaCl2 (aq) -------> BaSO4 (s) + 2NaCl (aq)


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