THE COMPLETE General Science Notes (Chemistry) for Railway Exams

Sep 5, 2026

Comprehensive chemistry-focused general science notes designed for railway exam preparation. The material explains physical and chemical changes, chemical reactions and the meaning of complete chemical equations, and outlines observations that indicate reactions such as changes in state, colour, gas evolution, and temperature variation. It covers balanced chemical equations, exothermic and endothermic reactions, and introduces major reaction types including combination, decomposition, displacement, and double displacement with relevant examples and reaction equations.

LanguageEnglish

CategoryExam

FormatPDF

Pages67

Reading Time2 h 49 min

AccessFree to download

General Science-Chemistry

Chemical reactions and equations

Matter

Atoms and molecules

Carbon and its compounds

Periodic Classification of Elements

Coal and petroleum

Acids Bases and Salts

Metals and Nonmetals

Combustion and Flame

Important chemicals and their uses

Important Chemistry one liners

| | | | | --- | --- | --- | | THE COMPLETE General Science Notes (Chemistry) for Railway Exams | | | | | | | | | | | | General Science-Chemistry
S.NO Content Page Number 1 Chemical reaction and equation 2 2 Matter 10 3 Atoms and molecules 21 4 Carbon and its compounds 29 5 Periodic Classification of Elements 34 6 Coal and petroleum 39
Page 1 of 67 | | | | | | | | Get High Standard Mock Test Series for all Bank Exams
If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: admin@exampundit.in | | | | | | | | --- | --- | --- | | THE COMPLETE General Science Notes (Chemistry) for Railway Exams | | | | | | | | 7 Acids Bases and Salts 44 8 Metals and Nonmetals 50 9 Combustion and Flame 57 10 Important chemicals and their uses 59 11 Important Chemistry one liners 60
CHEMICAL REACTIONS AND EQUATIONS
PHYSICAL CHANGES
Properties such as shape, size, colour and state of a substance are called its physical properties. A change in which a substance undergoes a change in its physical properties is called a physical change. A physical change is generally reversible. In such a change no new substance is formed.
CHEMICAL CHANGE
A change in which one or more new substances are formed is called a chemical change. A chemical change is also called a chemical reaction
CHEMICAL REACTION & EQUATIONS
􀁸 A complete chemical equation represents the reactants, products and their physical State symbolically.
􀁸 Following observations helps us to determine whether a chemical reaction has taken place
􀂃 Change in state
􀂃 Change in colour
􀂃 Evolution of a gas
􀂃 Change in temperature.
􀁸 Some of the example of chemical reactions in everyday life
􀂃 Photosynthesis
􀂃 Aerobic Cellular Respiration
􀂃 Combustion of wood
Page 2 of 67 | | | | | | | | Get High Standard Mock Test Series for all Bank Exams
If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: admin@exampundit.in | | | | | | | | --- | --- | --- | | THE COMPLETE General Science Notes (Chemistry) for Railway Exams | | | | | | | | 􀂃 Rusting of iron
􀂃 Metathesis
􀂃 Digestion
􀂃 Cooking an egg
􀂃 Souring of milk
􀂃 Rotting bananas
􀁸 Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light
􀁸 Reactions in which energy is absorbed are known as endothermic reactions.
BALANCED CHEMICAL EQUATIONS
􀁸 Mass can neither be created nor destroyed in a chemical reaction. That is, the total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants
􀁸 The number of atoms of each element remains the same, before and after a chemical reaction Some of the example of balanced equations
Zn + H2SO4- 􀃆ZnSO4 + H2
3Fe + 4H2O 􀃆Fe3O4 + 4H2
TYPES OF CHEMICAL REACTIONS
1. COMBINATION REACTION
􀁸 In a combination reaction two or more substances combine to form a new single Substance.
Example of combination reaction
􀁸 Calcium oxide reacts vigorously with water to produce slaked lime(calcium hydroxide) Releasing a large amount of heat
CaO (s) + H2O (l) -->Ca (OH)2 + Heat
􀁸 A solution of slaked lime produced by the above reaction is used for white washing wall
Page 3 of 67 | | | | | | | | Get High Standard Mock Test Series for all Bank Exams
If there are any suggestions/ errors in our PDFs Feel Free to contact us via this email: admin@exampundit.in | | | | | | | | --- | --- | --- | | THE COMPLETE General Science Notes (Chemistry) for Railway Exams | | | | | | | | NOTE: Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of whitewashing and gives a shiny finish to the walls. It is interesting to note that the chemical formula for marble is also CaCO3.

2. DECOMPOS

FAQs

What is the difference between physical and chemical changes?

Physical changes alter properties like shape, size, colour, or state without forming new substances and are generally reversible. Chemical changes form one or more new substances and are also called chemical reactions.

How can you tell that a chemical reaction has taken place?

Indicators include change in state, change in colour, evolution of a gas, and change in temperature.

What do balanced chemical equations mean?

In a balanced chemical equation, mass is conserved and the number of atoms of each element remains the same before and after the reaction.

Sep 5, 2026

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