Introduction and fundamental knowledge of chemistry

What is the chemistry?
Chemistry is a branch of physical science which describes the properties (chemical and physical ), chemical composition and also explains the transformations  occur in the matter when it either  exposed under energy or react with some other matter.

According to the Linus pauling, "Chemistry is the science of substances their properties their structure and their transformation."

Four main branches of chemistry are -

1. Inorganic chemistry 
2. Organic chemistry 
3. Physical chemistry 
4. Analytical chemistry

In inorganic chemistry we study all the aspects of elements and their compounds except organic compounds.

Through organic chemistry specially we study all the hydrocarbons and their derivatives.

In physical chemistry we study physical properties and constitution of matter the laws of chemical combination and theories governing reactions effect of temperature pressure light concentration etc on reactions also explains under physical chemistry.

In analytical chemistry we study the various methods of analysis of matter both quantitative and qualitative.

History of chemistry

The first book on chemistry was written in Egypt around 300 A.D. the term chemistry means that Egyptian art.

The French chemist  Lavoisier is regarded as father of chemistry.

Lavoisier explained in his experiment that necessity of oxygen in the combustion process. That is oxygen is necessary for the combustion of matter.

Some important chemist and their discoveries

Gay-lussac - Law of combining volumes of gases
Avogadro -  Avogadro hypothesis (1811)
Berzelius - Introduced the modern symbols for elements (1813)
Faraday - The law of electrolysis (1833)
Thomas Graham - Law of gaseous diffusion
Mendeleef - Periodic law and periodic table
Arrhenius - Theory of ionization


What is matter ?

Matter is anything that has mass and some volume. Example- water , iron etc

What is energy ?

The capacity to do work is termed as energy.

Energy - mass relation

The relationship between mass and energy was given by Einstein.  The relation can be expressed as
                                                   E=mC²

Where E = energy, m = mass, c = velocity of light (3*10⁸ m/s)

Simply it can be understand that The total amount of matter and energy available in the universe is always fixed.

Classification of matter

Matter is mainly of three types -
Solid
Liquid
Gas
There are two other types of matter also which are named as plasma and Bose Einstein condensate.

What is element ?

Elements are pure substances that consist only one type of atoms and cannot be decomposed into simpler substances by chemical methods. Example - Sodium (Na), Calcium(Ca) etc.

What are the compounds ?

When two or more than 2 different elements are mixed In a fixed composition by mass, then the product formed is termed as compound. Example - water (H₂O) etc.

Some specific properties of substance

Deliquescence - Property to absorb moisture from atmosphere.

Hygroscopicity  - Property to react with moisture present in atmosphere and form hydrates or hydroxides.

Efflorescence - Property to lose water of crystallization on exposure.

Malleability -  The property by which on hammering the substance converts into thin films our sheets.

Ductility - The property of metals to be drawn in wires is termed ductility.

Elasticity - When a substance stressed under a force and when external force is removed the substance regains its original shape this property of substance is known as elastic property.

Colligative properties - The properties which depends on number of moles of solute is known as colligative properties.

Intensive properties - The properties does not depends on the quantity of matter like color etc.

Extensive properties - The properties which depends on the quantity of matter like mass etc.

Isotropic -Every portion of substance has the same composition and same properties.

Anisotropic -Every portion of substance is not uniform that means has different properties at different point of substance.

What are the alloys ?

Open two or more elements or combined together the product so obtained is termed as alloy if it possess metallic character.Example - Brass ( Cu+Zn), Bronze (Cu+Sn) etc.


For Notes In Hindi   -  click here

Questions for readers - ( give your answer in comment box)

1) The most abundant element on earth's crust is -???

2) Sodium carbonate crystals lose water molecules. this property is called as -???

3) The direct change from solid state to gaseous state is termed as - ???