Some Basic Concepts of Chemistry Class 11 Notes Chemistry

 Page 1


  
 
 1 
 
 
 
 
 
 
Revision Notes 
Class 11 Chemistry 
Chapter 1 - Some Basic Concepts of Chemistry. 
                                            
1. CHEMISTRY 
Chemistry (derived from the Egyptian word keme (chem), which means 
"earth") is a science that studies the composition, structure and properties of 
matter and the changes it undergoes during chemical reactions. Chemistry is 
often referred to as core science because it plays a role in linking physical 
sciences (including chemistry) with life sciences and applied sciences (such as 
medicine and engineering). 
Chemistry is divided into following branches: 
 
1.1 Physical chemistry 
The branch of chemistry which deals with macroscopic as well as physical 
phenomena in a universe. It is generally the impact of physical property on the 
chemical property as well as structure of a substance. 
 
1.2 Inorganic chemistry 
The branch of chemistry that studies compounds that do not contain carbon and 
hydrogen atoms is called "inorganic chemistry." Simply put, it is the opposite 
of organic chemistry. Substances that do not have carbon-hydrogen bonds 
include metals, salts, and chemicals. 
 
1.3 Organic chemistry 
The discipline which deals with the study of the structure, composition and the 
chemical properties of organic compounds is known as organic chemistry. It 
involves the study of Carbon and its compounds. 
 
1.4 Biochemistry 
Biochemistry is that branch of chemistry that explores the chemical processes 
in organisms and associated with them. It's a laboratory-based science that 
connects biology and chemistry. By using chemical knowledge and technology, 
biochemists can understand and solve biological problems 
 
1.5 Analytical chemistry 
It is the branch of chemistry which uses instruments and analytical techniques 
to determine structure, functionality and properties of a substance. 
Page 2


  
 
 1 
 
 
 
 
 
 
Revision Notes 
Class 11 Chemistry 
Chapter 1 - Some Basic Concepts of Chemistry. 
                                            
1. CHEMISTRY 
Chemistry (derived from the Egyptian word keme (chem), which means 
"earth") is a science that studies the composition, structure and properties of 
matter and the changes it undergoes during chemical reactions. Chemistry is 
often referred to as core science because it plays a role in linking physical 
sciences (including chemistry) with life sciences and applied sciences (such as 
medicine and engineering). 
Chemistry is divided into following branches: 
 
1.1 Physical chemistry 
The branch of chemistry which deals with macroscopic as well as physical 
phenomena in a universe. It is generally the impact of physical property on the 
chemical property as well as structure of a substance. 
 
1.2 Inorganic chemistry 
The branch of chemistry that studies compounds that do not contain carbon and 
hydrogen atoms is called "inorganic chemistry." Simply put, it is the opposite 
of organic chemistry. Substances that do not have carbon-hydrogen bonds 
include metals, salts, and chemicals. 
 
1.3 Organic chemistry 
The discipline which deals with the study of the structure, composition and the 
chemical properties of organic compounds is known as organic chemistry. It 
involves the study of Carbon and its compounds. 
 
1.4 Biochemistry 
Biochemistry is that branch of chemistry that explores the chemical processes 
in organisms and associated with them. It's a laboratory-based science that 
connects biology and chemistry. By using chemical knowledge and technology, 
biochemists can understand and solve biological problems 
 
1.5 Analytical chemistry 
It is the branch of chemistry which uses instruments and analytical techniques 
to determine structure, functionality and properties of a substance. 
  
 
 2 
 
 
 
 
 
 
2. MATTER 
Matter is defined as any thing that have some mass and also occupies a certain 
volume in a space. 
Generally matter is classified into three phases: 
• Solid- The substance which have a definite shape as well as maintain 
its volume as per it’s shape, also they have least freedom of movement. 
e.g., sugar, iron, gold, wood etc. 
• Liquid- A substance is a substance which generally possess the shape 
of a container but have a fixed volume. Also liquids have the property 
to flow or to be poured. E.g., water, milk, oil, mercury, alcohol etc. 
• Gas- Substances which do not have a definite volume as well as 
definite shape. Gases generally completely fill the container they are 
kept in. E.g., hydrogen, oxygen etc. 
The three states are interconvertible by changing the conditions of 
temperature and pressure as follows: 
 
(taken from original pdf) 
3. CLASSIFICATION OF MATTER AT MACROSCOPIC LEVEL 
Matter can further be classified into following at bulk or macroscopic level: 
(a) Mixtures (b) Pure Substances. 
These can be further classified as shown below: 
Page 3


  
 
 1 
 
 
 
 
 
 
Revision Notes 
Class 11 Chemistry 
Chapter 1 - Some Basic Concepts of Chemistry. 
                                            
1. CHEMISTRY 
Chemistry (derived from the Egyptian word keme (chem), which means 
"earth") is a science that studies the composition, structure and properties of 
matter and the changes it undergoes during chemical reactions. Chemistry is 
often referred to as core science because it plays a role in linking physical 
sciences (including chemistry) with life sciences and applied sciences (such as 
medicine and engineering). 
Chemistry is divided into following branches: 
 
1.1 Physical chemistry 
The branch of chemistry which deals with macroscopic as well as physical 
phenomena in a universe. It is generally the impact of physical property on the 
chemical property as well as structure of a substance. 
 
1.2 Inorganic chemistry 
The branch of chemistry that studies compounds that do not contain carbon and 
hydrogen atoms is called "inorganic chemistry." Simply put, it is the opposite 
of organic chemistry. Substances that do not have carbon-hydrogen bonds 
include metals, salts, and chemicals. 
 
1.3 Organic chemistry 
The discipline which deals with the study of the structure, composition and the 
chemical properties of organic compounds is known as organic chemistry. It 
involves the study of Carbon and its compounds. 
 
1.4 Biochemistry 
Biochemistry is that branch of chemistry that explores the chemical processes 
in organisms and associated with them. It's a laboratory-based science that 
connects biology and chemistry. By using chemical knowledge and technology, 
biochemists can understand and solve biological problems 
 
1.5 Analytical chemistry 
It is the branch of chemistry which uses instruments and analytical techniques 
to determine structure, functionality and properties of a substance. 
  
 
 2 
 
 
 
 
 
 
2. MATTER 
Matter is defined as any thing that have some mass and also occupies a certain 
volume in a space. 
Generally matter is classified into three phases: 
• Solid- The substance which have a definite shape as well as maintain 
its volume as per it’s shape, also they have least freedom of movement. 
e.g., sugar, iron, gold, wood etc. 
• Liquid- A substance is a substance which generally possess the shape 
of a container but have a fixed volume. Also liquids have the property 
to flow or to be poured. E.g., water, milk, oil, mercury, alcohol etc. 
• Gas- Substances which do not have a definite volume as well as 
definite shape. Gases generally completely fill the container they are 
kept in. E.g., hydrogen, oxygen etc. 
The three states are interconvertible by changing the conditions of 
temperature and pressure as follows: 
 
(taken from original pdf) 
3. CLASSIFICATION OF MATTER AT MACROSCOPIC LEVEL 
Matter can further be classified into following at bulk or macroscopic level: 
(a) Mixtures (b) Pure Substances. 
These can be further classified as shown below: 
  
 
 3 
 
 
 
 
 
 
 
Classification of matter (taken from original pdf) 
(a) Mixtures : A mixture is a substance in which two or more substance are 
present in any ratio. Primarily, It is of two types: Heterogeneous and 
Homogeneous mixtures. 
• Homogeneous mixture- Two substances are mixed to form a mixture  
such that there exist one single uniform phase i.e. composition of 
substances present is uniform. Sugar solution and air are thus, the 
examples of homogeneous mixtures. 
• Heterogeneous mixtures- Two or more substances are mixed which 
result in non-uniform composition throughout the mixture. Some of the 
examples are suspensions, mixture of two solids suppose salt and sugar. 
Note: Any distinct portion of matter that is uniform throughout in composition 
and properties is called a Phase. 
 
(b) Pure substances:- A material containing only one type of particle is called 
a pure substance. 
Note: In chemistry, Form of matter having constant chemical composition and 
chemical properties and they cannot be separated into component by physical 
methods. 
Pure substances are further divided as given below: 
 
• Element- An element is defined as a pure substance that contains only 
one kind of atoms and cannot be further broken down. The elements are 
further split into three classes based on their physical and chemical 
properties i.e. (1) Metals (2) Non- metals and (3) Metalloids. 
 
Page 4


  
 
 1 
 
 
 
 
 
 
Revision Notes 
Class 11 Chemistry 
Chapter 1 - Some Basic Concepts of Chemistry. 
                                            
1. CHEMISTRY 
Chemistry (derived from the Egyptian word keme (chem), which means 
"earth") is a science that studies the composition, structure and properties of 
matter and the changes it undergoes during chemical reactions. Chemistry is 
often referred to as core science because it plays a role in linking physical 
sciences (including chemistry) with life sciences and applied sciences (such as 
medicine and engineering). 
Chemistry is divided into following branches: 
 
1.1 Physical chemistry 
The branch of chemistry which deals with macroscopic as well as physical 
phenomena in a universe. It is generally the impact of physical property on the 
chemical property as well as structure of a substance. 
 
1.2 Inorganic chemistry 
The branch of chemistry that studies compounds that do not contain carbon and 
hydrogen atoms is called "inorganic chemistry." Simply put, it is the opposite 
of organic chemistry. Substances that do not have carbon-hydrogen bonds 
include metals, salts, and chemicals. 
 
1.3 Organic chemistry 
The discipline which deals with the study of the structure, composition and the 
chemical properties of organic compounds is known as organic chemistry. It 
involves the study of Carbon and its compounds. 
 
1.4 Biochemistry 
Biochemistry is that branch of chemistry that explores the chemical processes 
in organisms and associated with them. It's a laboratory-based science that 
connects biology and chemistry. By using chemical knowledge and technology, 
biochemists can understand and solve biological problems 
 
1.5 Analytical chemistry 
It is the branch of chemistry which uses instruments and analytical techniques 
to determine structure, functionality and properties of a substance. 
  
 
 2 
 
 
 
 
 
 
2. MATTER 
Matter is defined as any thing that have some mass and also occupies a certain 
volume in a space. 
Generally matter is classified into three phases: 
• Solid- The substance which have a definite shape as well as maintain 
its volume as per it’s shape, also they have least freedom of movement. 
e.g., sugar, iron, gold, wood etc. 
• Liquid- A substance is a substance which generally possess the shape 
of a container but have a fixed volume. Also liquids have the property 
to flow or to be poured. E.g., water, milk, oil, mercury, alcohol etc. 
• Gas- Substances which do not have a definite volume as well as 
definite shape. Gases generally completely fill the container they are 
kept in. E.g., hydrogen, oxygen etc. 
The three states are interconvertible by changing the conditions of 
temperature and pressure as follows: 
 
(taken from original pdf) 
3. CLASSIFICATION OF MATTER AT MACROSCOPIC LEVEL 
Matter can further be classified into following at bulk or macroscopic level: 
(a) Mixtures (b) Pure Substances. 
These can be further classified as shown below: 
  
 
 3 
 
 
 
 
 
 
 
Classification of matter (taken from original pdf) 
(a) Mixtures : A mixture is a substance in which two or more substance are 
present in any ratio. Primarily, It is of two types: Heterogeneous and 
Homogeneous mixtures. 
• Homogeneous mixture- Two substances are mixed to form a mixture  
such that there exist one single uniform phase i.e. composition of 
substances present is uniform. Sugar solution and air are thus, the 
examples of homogeneous mixtures. 
• Heterogeneous mixtures- Two or more substances are mixed which 
result in non-uniform composition throughout the mixture. Some of the 
examples are suspensions, mixture of two solids suppose salt and sugar. 
Note: Any distinct portion of matter that is uniform throughout in composition 
and properties is called a Phase. 
 
(b) Pure substances:- A material containing only one type of particle is called 
a pure substance. 
Note: In chemistry, Form of matter having constant chemical composition and 
chemical properties and they cannot be separated into component by physical 
methods. 
Pure substances are further divided as given below: 
 
• Element- An element is defined as a pure substance that contains only 
one kind of atoms and cannot be further broken down. The elements are 
further split into three classes based on their physical and chemical 
properties i.e. (1) Metals (2) Non- metals and (3) Metalloids. 
 
  
 
 4 
 
 
 
 
 
 
• Compound- A compound is a pure material that consists of two or 
more elements mixed in a defined mass proportion. Furthermore, a 
compound's qualities are distinct from those of its constituting 
elements. Moreover, the constituents of a compound cannot be 
separated into simpler substances by physical methods. They can only 
be separated by chemical methods. 
 
4. PROPERTIES OF MATTER 
Unique or characteristic properties is depicted by every substance. 
Physical properties and chemical properties are the two types of properties that 
are observed. 
 
4.1 Physical Properties 
Physical properties are those that may well be measured or observed without 
affecting the substance's identity or composition. Colour, fragrance, melting 
point, boiling point, density, and other physical qualities are some of 
the examples. 
 
4.2 Chemical properties 
Chemical properties are the properties of specific substances that can be 
observed in chemical reactions. Some of the main chemical properties include 
flammability, toxicity, heat of combustion, pH, radioactive decay rate, and 
chemical stability. 
 
5. MEASUREMENT 
5.1 Physical quantities 
Physical quantities are quantities which we encounter during our scientific 
study. Any physical quantity can be measured in two parts: 
(1) The number, and (2) The unit: Unit is defined as the reference standard 
chosen to measure any physical quantity. 
5.2 S.I. UNITS 
The International System of Units (in French Le Systeme International d’Unités 
– abbreviated as SI) was established by the eleventh  General Conference on 
Weights and Measures (CGPM from Conference Generale des Poids at 
Measures). The CGPM is an inter governmental treaty organization created by 
a diplomatic treaty known as Meter Convention which was signed in Paris in 
1875.  
Page 5


  
 
 1 
 
 
 
 
 
 
Revision Notes 
Class 11 Chemistry 
Chapter 1 - Some Basic Concepts of Chemistry. 
                                            
1. CHEMISTRY 
Chemistry (derived from the Egyptian word keme (chem), which means 
"earth") is a science that studies the composition, structure and properties of 
matter and the changes it undergoes during chemical reactions. Chemistry is 
often referred to as core science because it plays a role in linking physical 
sciences (including chemistry) with life sciences and applied sciences (such as 
medicine and engineering). 
Chemistry is divided into following branches: 
 
1.1 Physical chemistry 
The branch of chemistry which deals with macroscopic as well as physical 
phenomena in a universe. It is generally the impact of physical property on the 
chemical property as well as structure of a substance. 
 
1.2 Inorganic chemistry 
The branch of chemistry that studies compounds that do not contain carbon and 
hydrogen atoms is called "inorganic chemistry." Simply put, it is the opposite 
of organic chemistry. Substances that do not have carbon-hydrogen bonds 
include metals, salts, and chemicals. 
 
1.3 Organic chemistry 
The discipline which deals with the study of the structure, composition and the 
chemical properties of organic compounds is known as organic chemistry. It 
involves the study of Carbon and its compounds. 
 
1.4 Biochemistry 
Biochemistry is that branch of chemistry that explores the chemical processes 
in organisms and associated with them. It's a laboratory-based science that 
connects biology and chemistry. By using chemical knowledge and technology, 
biochemists can understand and solve biological problems 
 
1.5 Analytical chemistry 
It is the branch of chemistry which uses instruments and analytical techniques 
to determine structure, functionality and properties of a substance. 
  
 
 2 
 
 
 
 
 
 
2. MATTER 
Matter is defined as any thing that have some mass and also occupies a certain 
volume in a space. 
Generally matter is classified into three phases: 
• Solid- The substance which have a definite shape as well as maintain 
its volume as per it’s shape, also they have least freedom of movement. 
e.g., sugar, iron, gold, wood etc. 
• Liquid- A substance is a substance which generally possess the shape 
of a container but have a fixed volume. Also liquids have the property 
to flow or to be poured. E.g., water, milk, oil, mercury, alcohol etc. 
• Gas- Substances which do not have a definite volume as well as 
definite shape. Gases generally completely fill the container they are 
kept in. E.g., hydrogen, oxygen etc. 
The three states are interconvertible by changing the conditions of 
temperature and pressure as follows: 
 
(taken from original pdf) 
3. CLASSIFICATION OF MATTER AT MACROSCOPIC LEVEL 
Matter can further be classified into following at bulk or macroscopic level: 
(a) Mixtures (b) Pure Substances. 
These can be further classified as shown below: 
  
 
 3 
 
 
 
 
 
 
 
Classification of matter (taken from original pdf) 
(a) Mixtures : A mixture is a substance in which two or more substance are 
present in any ratio. Primarily, It is of two types: Heterogeneous and 
Homogeneous mixtures. 
• Homogeneous mixture- Two substances are mixed to form a mixture  
such that there exist one single uniform phase i.e. composition of 
substances present is uniform. Sugar solution and air are thus, the 
examples of homogeneous mixtures. 
• Heterogeneous mixtures- Two or more substances are mixed which 
result in non-uniform composition throughout the mixture. Some of the 
examples are suspensions, mixture of two solids suppose salt and sugar. 
Note: Any distinct portion of matter that is uniform throughout in composition 
and properties is called a Phase. 
 
(b) Pure substances:- A material containing only one type of particle is called 
a pure substance. 
Note: In chemistry, Form of matter having constant chemical composition and 
chemical properties and they cannot be separated into component by physical 
methods. 
Pure substances are further divided as given below: 
 
• Element- An element is defined as a pure substance that contains only 
one kind of atoms and cannot be further broken down. The elements are 
further split into three classes based on their physical and chemical 
properties i.e. (1) Metals (2) Non- metals and (3) Metalloids. 
 
  
 
 4 
 
 
 
 
 
 
• Compound- A compound is a pure material that consists of two or 
more elements mixed in a defined mass proportion. Furthermore, a 
compound's qualities are distinct from those of its constituting 
elements. Moreover, the constituents of a compound cannot be 
separated into simpler substances by physical methods. They can only 
be separated by chemical methods. 
 
4. PROPERTIES OF MATTER 
Unique or characteristic properties is depicted by every substance. 
Physical properties and chemical properties are the two types of properties that 
are observed. 
 
4.1 Physical Properties 
Physical properties are those that may well be measured or observed without 
affecting the substance's identity or composition. Colour, fragrance, melting 
point, boiling point, density, and other physical qualities are some of 
the examples. 
 
4.2 Chemical properties 
Chemical properties are the properties of specific substances that can be 
observed in chemical reactions. Some of the main chemical properties include 
flammability, toxicity, heat of combustion, pH, radioactive decay rate, and 
chemical stability. 
 
5. MEASUREMENT 
5.1 Physical quantities 
Physical quantities are quantities which we encounter during our scientific 
study. Any physical quantity can be measured in two parts: 
(1) The number, and (2) The unit: Unit is defined as the reference standard 
chosen to measure any physical quantity. 
5.2 S.I. UNITS 
The International System of Units (in French Le Systeme International d’Unités 
– abbreviated as SI) was established by the eleventh  General Conference on 
Weights and Measures (CGPM from Conference Generale des Poids at 
Measures). The CGPM is an inter governmental treaty organization created by 
a diplomatic treaty known as Meter Convention which was signed in Paris in 
1875.  
  
 
 5 
 
 
 
 
 
 
There are seven base units in SI system as listed below 
These units pertain to the seven fundamental scientific quantities. The other 
physical quantities such as speed, volume, density etc. can be derived from 
these quantities. The definitions of the SI base units are given below: 
 
Unit of length  
 
 
 
 
 
 
Unit of mass  
 
 
 
 
 
Unit of time  
 
 
 
 
 
 
 
 
 
Unit of electric current  
 
 
 
 
 
 
 
 
 
 
 
Metre 
 
 
 
 
 
 
Kilogram 
 
 
 
 
 
Second  
 
 
 
 
 
 
 
 
 
Ampere  
 
 
 
 
 
 
 
 
 
 
 
The metre is the length 
of the path travelled by 
light in vacuum during 
a time interval of 
1
299
 792 458 of a 
second. 
 
The kilogram is the 
unit of mass; it is equal 
to the mass of the 
international prototype 
of the kilogram. 
 
The second is the 
duration of 
9 192 631 770 
periods of the radiation 
corresponding to the 
transition between the 
two hyperfine levels of 
the ground state of the 
caesium 133 - atom. 
 
The ampere is that 
constant current 
which, if maintained in 
two straight parallel 
conductors of infinite 
length, of negligible 
circular cross-section, 
and placed 1  metre 
apart 
in vacuum, would 
produce between these 
conductors a force