Define Chemistry: Chemistry is the branch of science in which we study about matter. We can study composition,structure,properties and chemical reactions of matter. We know that every things in this world is made up of matter. Why and how many substances combine and separate with each other? We study in chemistry about this questions. The chemical reaction are taking place in every aspect of life. Our life without chemistry is nothing and we considered dead if we remove chemistry from our life. So chemistry is main and most important part of our life. Chemistry paly an important role in human as well as in animal life.
Branches Of Chemistry
There are many branches of chemistry because chemistry is present in every aspect of life. Some main branches of chemistry are given below.
- Organic chemistry:
The branch of chemistry in which we study about hydrocarbons and their derivatives.
Hydrocarbons are formed from carbon and hydrogen by covalent bond. The hydrocarbons are found naturally and they are also prepared in laboratory. These compound play an important role in petroleum and medicine field.
- Inorganic Chemistry:
The branch of chemistry in which we study about all elements accept carbon and hydrogen. We study all compounds accept hydrocarbons. These compound play an important role in metallurgy, cement,ceramic and mirrors industry.
- Biochemistry:
The branch of chemistry in which we study about elements that are found in the body of living organisms. We study about their structure, composition and chemical reactions. Carbohydrates, proteins ,lipids are main topics that are discussed in biochemistry. This is main branch of chemistry that play an important and effective role in the life of living things.
- Industrial chemistry:
The branch of chemistry in which we study about the manufacturing of compounds on commercial scale.
Oxygen,chlorine,ammonia,soap,detergents,oil and fertiliser are manufactured.
The Branch of chemistry in which we study about composition, physical properties and changing taking place in matter. We also study about atomic structure, gases,liquid and solid state of matter and effect of temperature on these state.
The branch of chemistry in which we study about radioactivity,nuclear reactions and nuclear properties.
We can gain energy and used that energy in beneficial purpose.
The branch of chemistry in which we study about environment and effect of human activities on environment. Biotic and a biotic factors are also studied.
Matter: Any thing having mass and occupy space is called matter.
For example: wood chair air table water
Atomic Number :
In the nucleus of an atom the number of protons are known as atomic number.
The symbol of atomic number is Z.
Atomic of hydrogen, Oxygen and Carbon is 1,8,6 respectively.
Atomic Mass:
The number of proton and neutron in the nucleus of an atom is called atomic mass.
Proton and neutron are also known as nucleons. The symbol of atomic mass is A.
A=Z+n
Atomic mass of carbon, Nitrogen and oxygen is 12 14 and 16 respectively.
Empirical Formula:
The simplest form of formula is called empirical formula. Empirical Formula of glucose is CH2O
Molecular Formula:
The formula that show the total number of atom in a molecule. Molecular Formula of glucose is C6H12O6.
Atom or group of atom having positive or negative charge is called Ions.
There are two types of ions. Cations and Anions.
Cations: ions having positive chagre is called cations. Na+ , Ca+2
When an atom lose one or more electrons than cations are formed.
Anions: Ions having negative charge is called anions. Cl- F-
When an atom gain one or more electrons than anions are formed.
Free Radicals: Atoms or group of atoms having odd number of electron are called free radical. It's symbol is dott (•)
For example H• , C• and Cl•
Types of Molecules:
There are many types of molecule, some are given below.
1. Mono Atomic Molecule:
A molecule having just one atom is called mono atomic molecule.
For example Helium and Neon
2. Diatomic molecule :
A molecule having two atoms is known as diatomic molecule. For example O2, HCl
3. Triatomic Molecules:
A molecule having three atoms is known as triatomic molecule. For example H2O , CO2
4. Polyatomic molecule:
A molecule having many atoms is known as polyatomic molecule. For example C6H12O6 ,H2SO4
5. Homoatomic Molecules:
Molecules having same type of atom and all atoms present in a single elements. For example S8,O3 and P4.
6. Hetroatomic Molecules:
When a molecule having different types of atoms than it is known as hetroatomic molecule. For example NH3 , CO2
- Physical Chemistry:
The Branch of chemistry in which we study about composition, physical properties and changing taking place in matter. We also study about atomic structure, gases,liquid and solid state of matter and effect of temperature on these state.
- Nuclear Chemistry:
The branch of chemistry in which we study about radioactivity,nuclear reactions and nuclear properties.
We can gain energy and used that energy in beneficial purpose.
- Environmental Chemistry:
The branch of chemistry in which we study about environment and effect of human activities on environment. Biotic and a biotic factors are also studied.
Basic Definitions:
Matter: Any thing having mass and occupy space is called matter.
For example: wood chair air table water
Atomic Number :
In the nucleus of an atom the number of protons are known as atomic number.
The symbol of atomic number is Z.
Atomic of hydrogen, Oxygen and Carbon is 1,8,6 respectively.
Atomic Mass:
The number of proton and neutron in the nucleus of an atom is called atomic mass.
Proton and neutron are also known as nucleons. The symbol of atomic mass is A.
A=Z+n
Atomic mass of carbon, Nitrogen and oxygen is 12 14 and 16 respectively.
Empirical Formula:
The simplest form of formula is called empirical formula. Empirical Formula of glucose is CH2O
Molecular Formula:
The formula that show the total number of atom in a molecule. Molecular Formula of glucose is C6H12O6.
- Ions and formation of ions:
Atom or group of atom having positive or negative charge is called Ions.
There are two types of ions. Cations and Anions.
Cations: ions having positive chagre is called cations. Na+ , Ca+2
When an atom lose one or more electrons than cations are formed.
Anions: Ions having negative charge is called anions. Cl- F-
When an atom gain one or more electrons than anions are formed.
Free Radicals: Atoms or group of atoms having odd number of electron are called free radical. It's symbol is dott (•)
For example H• , C• and Cl•
- Molecule: when two or more atoms combine with each other by chemical reaction than new species are formed known as molecule . Molecules existence independently.
Types of Molecules:
There are many types of molecule, some are given below.
1. Mono Atomic Molecule:
A molecule having just one atom is called mono atomic molecule.
For example Helium and Neon
2. Diatomic molecule :
A molecule having two atoms is known as diatomic molecule. For example O2, HCl
3. Triatomic Molecules:
A molecule having three atoms is known as triatomic molecule. For example H2O , CO2
4. Polyatomic molecule:
A molecule having many atoms is known as polyatomic molecule. For example C6H12O6 ,H2SO4
5. Homoatomic Molecules:
Molecules having same type of atom and all atoms present in a single elements. For example S8,O3 and P4.
6. Hetroatomic Molecules:
When a molecule having different types of atoms than it is known as hetroatomic molecule. For example NH3 , CO2
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