NCERT Class 10 Science Chapter 1 Notes Chemical Reactions and Equations- Download PDF Notes

NCERT Class 10 Science Chapter 1 Notes Chemical Reactions and Equations- Download PDF Notes

Edited By Irshad Anwar | Updated on Mar 19, 2024 06:17 PM IST

The chemical reactions and equations is a very important chapter of the NCERT Class 10th from an exam point of view. The NCERT Class 10 Science Chapter 1 notes give you a basic idea of the chapter chemical reactions and equations. The main topics covered in Chapter 1 NCERT Class 10 Science notes are definitions, examples, chemical equations and how to balance them, types of chemical reactions, the effects of oxidation reactions in everyday life. Download the CBSE Notes for Class 10 Science, Chemistry Chapter 1, PDF to use offline anywhere. Students must go through each topic in the chemical reactions and equations in Class 10 Notes Science in the easiest and most effective way possible with the help of NCERT Notes for Class 10.

Class 10 Science chapter 1 notes also cover all the important concepts related to this chapter, which are useful in various competitive exams. Chemical reactions and equations NCERT Notes for Class 10 Science help you revise these major concepts given in the NCERT Book in no time during CBSE Board exam preparation. CBSE Class 10 Science Chapter 1 notes will help you with quick revision. The Chemical Reactions and Equations chapter covers all headings of NCERT Textbook. CBSE Class 10 Science chapter 1 notes also contain important examples that have been frequently asked in the various exams. Having revision notes and NCERT Solutions for Class 10 Chemistry Chapter 1 handy is beneficial to save you time.The NCERT Class 10 notes pdf can be downloaded through the link given below.

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NCERT Class 10 Chapter 1 Class Notes

Chemical Reactions and Equations

  • This chapter focuses on the balanced and unbalanced chemical reactions and how to balance them.
  • This chapter focused on the importance of chemical equations and their representation by using various symbols and notations.
  • Understanding chemical reactions is always a base for science students.
  • CBSE Class 10 Science chapter 1 notes also contain some very common reactions taking place in our surroundings.

Chemical Reaction

  • The conversion of chemical substances into another chemical substance is known as a chemical reaction.
  • Some of the chemical reactions are rusting of the iron setting of milk into curd respiration etc.
  • The new chemical substance formed will be completely different from the parent substance and only then it can be called a chemical reaction.
  • And the change taking place on them can be called a chemical change.
  • In a chemical reaction, the rearrangement of atoms takes place.

Reactants-

The one that is taking part in a chemical reaction is a reactant.

Products-

The new substance that is formed after a chemical reaction is called a product.

Example-

Magnesium burns in the air to form magnesium oxide is a type of chemical reaction.

Mg+O2 Heat →2MgO(s)

In this reaction, the reactants are magnesium and oxygen while the new substance MgO is the product.

Characteristics of Chemical Reaction

  • Evolution of gas: In some reactions, there is an evolution of gas for example the reaction between zinc and dilute sulphuric acid is followed by the evolution of hydrogen gas. It can be represented as

Zn+H2SO4→ZnSO4+H2

  • Change in color: In some other reactions, there may be a change in color. For example, when citric acid and purple color potassium permanganate solution undergo a chemical reaction there is a change in color from purple to colorless. And also the chemical reaction between sulfur dioxide and acidified potassium dichromate solution is also followed by a change in color from orange to green.

  • Change in-state: For some chemical reactions, there is a change in the state of the substance. For example, when candle wax undergoes a combustion reaction there is a change of state from solid to liquid and gas. And the gas formed in this type of reaction is carbon dioxide.

  • Change in temperature: For some reactions, there is a change in temperature that is a rise in temperature or a fall in temperature occurs. For example, the reaction between quicklime and water to form slaked lime is followed by a rise in temperature. And also the reaction taking place between zinc granules and dilute sulphuric acid is also followed by a rise in temperature.

  • Formation of the precipitate: In the reaction between a sulphuric acid and barium chloride solution, it occurs the formation of a white precipitate of barium sulfate.

BaCl2+H2SO4→BaSO4(s )+2HCl

Chemical Equations

  • For representing a chemical reaction some simple and formulas can be used and this representation is called a chemical equation. For example, when A and B are a reactant and C and D are the products formed after a reaction the following representation can be used to represent reaction.

A+B→C+D

  • When hydrogen undergoes a reaction with oxygen water is formed. In which the hydrogen and oxygen is the reactant and the water obtained is the product can be represented as

H2+O2 H2O

  • So with the help of a chemical equation we can represent it in a concise and informative way. It can also be divided into two types of balance the chemical equation and unbalanced chemical equation.

Balanced Chemical Equation

When the number of atoms of each element in a chemical reaction is equal on both sides it is called a balanced chemical equation.

Zn+H2SO4 ZnSO4+H2

Unbalanced the Chemical Equation

When the number of atoms of each element in the reactant and product side is not equal it is called an unbalanced chemical equation.

Fe+H2O→ Fe3O4+H2

In this reaction the number of atoms of the element iron is not equal and also oxygen is also not equal. So we need to balance that unbalanced equation to its balanced form.

In this chemical equation, 3 iron is formed at the product side so we need to multiply iron with 3 on the reactant side. And also the oxygen atom formed at the product is four so the water is also multiplied by 4. So to balance both sides hydrogen evolved should also be multiplied by 4.

3Fe+4H2O→ Fe3O4+4H2

So the unbalanced equation becomes a balanced equation. In the representation of the chemical equation, the state can also be mentioned that is whether it is in the gaseous form or liquid form or solid form can be given by descending with brackets.

Types of Chemical Reactions

Combination Reaction

the chemical reaction in which two or more reactance are combined to form another product is a combination reaction. That is,

A+B→ AB

Magnesium reacts with oxygen to form magnesium oxide is a typical example of this reaction.

2Mg+O2 Heat→2MgO(s)

Decomposition reaction

When one compounder decomposes into two or more compounds it is called a decomposition reaction. That is,

AB→ A+B

A typical example of a decomposition reaction is the formation of calcium oxide and carbon dioxide by the decomposition of calcium carbonate.

CaCO3(s) Heat→ CaO+CO2(g)

Thermal decomposition is when a substance undergoes a decomposition reaction by heating it is thermal decomposition.

CaCO3(s) Heat→ CaO+CO2(g)

Electrolytic decomposition is the reaction signature a compound decomposes into another component by the supply of electricity is electrolytic decomposition. Electrolysis is a type of electrolytic decomposition.

For example, when electricity is passed in water it will decompose into oxygen and hydrogen. That is,

2H2O→2H2+O2

Photolysis or Photodecomposition

The decomposition reaction performed in the presence of sunlight is known as photolysis. For example, when silver chloride is put in the sunlight it will decompose to produce the metal silver and chlorine gas. The reaction is,

2AgCl sunlight→ 2Ag+Cl2

Displacement Reaction

A chemical reaction in which a reactive element is replaced with a less reactive element is a displacement reaction. It can be represented as,

A+BC→ AC+B

The reaction taking place between Zinc and hydrochloric acid is an example of a displacement reaction.

Zn+2HCl→ ZnCl2+H2

Precipitation Reaction

The reaction in which a precipitate is formed after the chemical reaction is called a precipitation reaction. An example for it is,

AgNO3+NaCl→ AgCl(s)+NaNO3

AgCl is the precipitate.

Neutralisation Reaction

A chemical reaction in which acid and a base undergo a reaction to form a neutral product that is water is called a neutralisation reaction.

NaOH+HCl→ NaCl+H2O

Oxidation Reaction

The removal of hydrogen or metallic element and the addition of oxygen or nonmetallic element from a compound is known as oxidation. The element in which the nonmetallic element or oxygen is added and hydrogen or metallic element is removed is said to be oxidized.

Example: Rusting iron.

Reduction Reaction

Removal of oxygen or nonmetallic element and addition of hydrogen or metallic element from any compound is called reduction. And the element in which it will undergo A reduction process is said to be reduced.

Redox Reaction

When the process of reduction and oxidation takes place simultaneously it is said to be a redox reaction. And the substance which removes hydrogen or gives oxygen is said to be an oxidizing agent. And the one which gives hydrogen or removes oxygen is said to be a reducing agent.

CuO+H2 Cu+H2O

In this reaction oxygen is removed from CuO therefore it is said to be a reduction process. While oxygen is added to H2 so it is an oxidation process.

Exothermic Reaction

The reaction in which energy is produced is called an exothermic reaction. And the energy is produced in the form of heat.

CaO+H2O→ Ca(OH)2+Energy

Endothermic Reaction

When heat energy is absorbed or consumed to undergo a chemical reaction it is an endothermic reaction.

CaCO3 Heat→ CaO+CO2

Chapter-Wise NCERT Class 10 Notes Science

Significance of NCERT Notes for Class 10 Science Chapter 1

NCERT Class 10 science chapter 1 notes contain a simple and brief overview of chemistry chapter 1. These Notes for Class 10 science chapter 1 are also beneficial for covering the core concepts of the CBSE Class 10 Syllabus 2024 PDF as well as for competitive exams such as AIPMT, AIIMS, NEET, and other similar exams. Class 10 science chapter 1 notes pdf download can be utilized for offline preparation. Notes for Class 10 Science chapter 1 focus on the important points regarding the chemical reaction and equations. The notes for Class 10 Science chapter 1 helps students to perform better in their examinations and also provide a complete revision before they are going to attempt the examination. Class 10 Science chapter 1 notes pdf download is also very helpful for students who wishes to write and crack NEET and JEE MAIN examinations. Chemical Reactions and Equations Class 10 notes help students in getting good marks while learning in the offline mode.

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Frequently Asked Questions (FAQs)

1. What are the things that must be present in a chemical equation?

A chemical equation consists of two sides on one side where reactants are represented and on another side product is represented and these two are separated usually by an arrow. This is clearly explained in the Class 10 the Chemical Reactions and Equations notes.

2. Why is the use of chemical equations important?

Chemical equations clearly explain what are the chemicals involved and also what are the products obtained after a reaction has been completed.

3. What are the types of chemical reactions?

Decomposition, combination, displacement, redox, neutralization, etc. Details of these reactions are clearly explained in the Chemical Reactions and Equations Class 10 notes pdf download.

4. How can we balance a chemical equation?

To balance a chemical reaction the number of atoms or elements on both sides of the chemical equation is made the same. Thus we can balance a chemical equation. This is also explained in the NCERT notes for Class 10 Science Chapter 1.

5. What is the only thing that cannot be changed to balance a chemical equation?

The number of atoms on both sides of the chemical equation cannot be changed.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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