Types of Chemical Reactions

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.

Example:

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)

 

 

Chemical Reactions Quiz

1. Chemical Reaction, 2H₂O → 2H₂ + O₂ is a-

Synthesis Reaction
Decomposition Reaction
Combustion Reaction
Single Displacement Reaction
Double Displacement Reaction

Polymer, Polymerization and Polymer Classification

Polymer And Polymerization

Condensation Polymer: Nylon-6-6, Terylene.

Addition Polymer: Polythene, Neoprene.

Polymer Classification

Polymer Classification on the basis of Source:

1.    Natural Polymer: 

                                  These are polymers which found in nature (in plants and animals). Example- Protein, Cellulose, Rubber.

2.    Semi-synthetic Polymer: 

                                         These are polymers which are prepared by treating naturally occurring polymers. Example- Cellulose Derivatives as cellulose acetate (Rayon), Cellulose Nitrate.

3.    Synthetic Polymer: 

                              These are polymers which are prepared by human beings in industry. Example- Plastic (Polyethene), Synthetic Fibers ( Nylon 6-6), Buna-S.

Polymer Classification on the basis of Structure:

1.    Linear Polymer: 

                                These are polymers which contain long and straight chains. Example- High Density Polythene, Polyvinyl Chloride.

2.    Branched Chain Polymer: 

                                                  These are polymers which contain linear chains with some branches. Example- Low Density Polythene.

3.     Cross Linked or Network Polymer: 

                                                                These are polymers which contain bi & tri functional monomers and contain very strong covalent bonds between the various linear polymer chains. Example- Bakelite, Melamine.

Polymer Classification on the basis of Molecular Forces:

1.    Elastomers: 

                     These are polymers which have elastic property means they can be stretched. Example- Weak intermolecular forces. eg.- Natural Rubber, Synthetic Rubber.

2.    Fibers: 

            These are polymers which have thread forming property and possess high tensile strength, high modulus and strong intermolecular forces. Example- Polyamides (Nylon6-6), Polyesters (Terylene).

3.    Thermoplastic: 

                              These are polymers which have linear or slightly branched long chain molecules which are capable of repeatedly softening on applying heating and hardening on applying cooling. Example- Polythene, Polystyrene.

4.    Thermosetting: 

                              These polymers contain cross linked and heavily branched molecules. These polymers on heating undergo extensive cross linking in moulds. Thermosetting polymers can't be reused. Example- Bakelite, Urea Formaldehyde Resins.

Chemistry Terminology by:- www.ChemistryNotesInfo.com

Polymer And Polymerization

Polymer And Polymerization

Condensation Polymer: Nylon-6-6, Terylene.

Addition Polymer: Polythene, Neoprene.

Polymer Classification

Polymer Classification on the basis of Source:

1.    Natural Polymer: Protein, Cellulose, Rubber.

2.    Semi-synthetic Polymer: Cellulose Derivatives as cellulose acetate (Rayon), Cellulose Nitrate.

3.    Synthetic Polymer: Plastic (Polyethene), Synthetic Fibers ( Nylon 6-6), Buna-S.

Polymer Classification on the basis of Structure:

1.    Linear Polymer: High Density Polythene, Polyvinyl Chloride.

2.    Branched Chain Polymer: Low Density Polythene.

3.     Cross Linked or Network Polymer: Bakelite, Melamine.

Polymer Classification on the basis of Molecular Forces:

1.    Elastomers: Weak intermolecular forces. eg.- Natural Rubber, Synthetic Rubber.

2.    Fibers: Strong intermolecular forces. eg.- Polyamides (Nylon6-6), Polyesters (Terylene).

3.    Thermoplastic: Polythene, Polystyrene.

4.    Thermosetting: Bakelite, Urea Formaldehyde Resins.

Chemical Equations

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 +  H₂O -----> 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	Notation
Gaseous	(g)
Liquid	(l)
Aqueous	(aq)
Solid	(s)

Example: 3Fe (s) + 4H₂O (g) ----> Fe₃O₄ (s) + 4H₂ (g)

·       Example of reactions with reaction condition like pressure, temperature, catalyst etc.

Liquid State

Liquid State

Intermolecular forces in liquids are stronger than in gases. Liquid have definite (fix) volume and they can flow and take the shape of the container in which these liquids are stored. These online education classes degree notes are published by ChemistryNotesInfo.com and hosted at ChemistryNotesInfo.blogspot.com Vapour pressure, viscosity, surface tension are some physical properties of liquids which are described below-

Vapor Pressure: 

                    Pressure exerted by the vapors on the walls of the container containing liquid is known as vapour pressure.

·       Vaporization depends on temperature

·   Vapour pressure at which equilibrium is achieved between liquid phase and vapor phase is known as Saturated Vapour Pressure or Equilibrium Vapour Pressure

·      Boiling is a condition of free vaporization means vapor extends freely into the surroundings.

·       Boiling temp. at 1 atm pressure is known as Normal Boiling Point

·       Boiling temp. at 1 bar pressure is known as Standard Boiling Point

·       Temp. at which clear boundary between liquid and vapors disappear is known as Critical Temperature

Surface Tension: 

                         Liquids tends to minimize their surface area because molecules of the liquid on the surface experience net attractive force towards the interior of the liquid, this characteristic property of the liquid is known as Surface Tension.

Example: Mercury do not form thin film and capillary action

Viscosity: 

              It is a measure of resistance to flow that arise due to internal friction between the layers of liquid (or fluid), when they slip over one another, during the flow of liquid or fluid.

·       Force required to maintain flow of liquid layers is-

                             F=Adu/dz

Where, A is area of contact,

du/dz is velocity gradient,

is coefficient of viscosity.

SI unit of is “Newton second per square meter (Nsm^-2)”

cgs unit of is “poise”

Read more education classes degree classes notes for School College University at www.ChemistryNotesInfo.com