Chemical Reactions And Equations Class 10 Notes CBSE Science Chapter 1

CBSE NCERT Class 10 Notes Science contains physics, chemistry and biology notes of chapter 1 Chemical Reactions And Equations topics given in textbook are part of Revision Notes for Class 

Science Notes cover an overview of the main given points of every concepts and Topics in the NCERT TextBooks Class 10th Science this Chapter Notes includes topic/concepts wise explanations for all the topic provided in the book such as Burning, Rusting, Respiration, Formation of Curd and Chemical reactions

Well prepared Class 10th Science  all Chapters Notes will guidance students understand the topics ,concepts and themes covered in all the chapters of Ncert Text book of 10th 

Chemical reaction:

The process in which new substances with new properties are formed from one or more substances is called Chemical Reaction.

Examples –

– Rusting of Iron

– Burning of wood

– Formation of Curd

– Respiration etc.

Following observations help to determine whether a chemical 

reaction has taken place:

1) Change in state

2) Change in colour

3) Evolution of a gas

4) Change in temperature

Reactant: The substances which take part in chemical reaction.

Product: The substances which are formed in a chemical reaction.

Chemical Equation:

– Symbolic representation of a chemical reaction is said to be 

Chemical equation.

– It involves uses of symbol of elements or chemical formula of 

reactant and product with mention of physical state.

The necessary conditions such as temperature, pressure or any 

catalyst should be written on arrow between reactant and products.

– Example :

Magnesium is burnt into air to form magnesium oxide can be 

represented as

 Mg + O2 →MgO

Important Note

Physical state of the reactant and products are mentioned to make chemical reaction more informative.

Example we use (g) for gas, (l) for liquid, (s) for solid and (aq) for aqueous. Thus is good for chemical reactions and equations notes 

Balancing Chemical Equation:

Chemical reactions and equations notes also include the mean to balance the equations by several methods. They are:

Law of Conservation of Mass –

– Mass can neither be created nor be destroyed in a chemical reaction. Thus remains conserved. 

– So number of elements involved in product side will be same as 

reactant side.

H2 + O2 → H2O. 

– In this Chemical equation number of H atoms in reactant side 

is 2 and that of product side is also 2. Number of O atoms in reactant side is 2 but that of product side is 1.

– To balance this equation, we have to use hit and trial method.

2H2 + O2 → 2H2O

– Now the number of atoms in reactant side is equal to that of product side.

Thus, balanced.

Types of Chemical Reactions

There are several types of chemical reaction based on different 

factors –

Based on Chemical Change:

There are total 8 types of Chemical reactions –

1) Combination Reaction –

 The reaction in which two or more substances combine to form a new single substance.

C + O2 → CO2

2) Decomposition reaction 

 The reaction in which a single substance decomposes to give two or more substances.

Nacl → Na + Cl 

Decomposition reactions can be of three types –

i) Thermal Decomposition – 

When a decomposition reaction is carried out by heating.

CaCO3 → CaO + CO2

ii) Electrolytic Decomposition – When decomposition is carried out by passing electricity.

2H2O + electric current → 2H2 + O2

iii) Photolytic Decomposition – When decomposition is carried out in presence of sunlight.

2AgCl + sunlight → 2Ag (s) + Cl2

3) Displacement Reaction – The chemical Reaction in which an element displaces another element from its solution.

Fe + CuSO4 → FeSO4 + Cu

4) Double Displacement Reaction – The reaction in which two different atoms or group of atoms are mutually exchanged.

Na2SO4 + BaCl2 → BaSO4 + 2NaCl

5) Precipitation reaction – The reaction which involves formation of precipitate (insoluble substance) is known as precipitation

reaction.

Pb(NO3)2 + 2KI → 2KNO3 + PbI2 

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