# Chemical Reaction and Equations Class 10 Science Chapter 1 Notes NCERT Solution

NCERT Class 10 Science Chapter 1 Chemical Reaction and Equations Notes Solution For School Students of Class 10th. We also Provides Notes and Important Questions for Class 10 Science. NCERT Class 10th Science book is applied in mostly boards like CBSE, HBSE, RBSE, Up Board, MP Board and also some other state boards.

Also Read:- Class 10 Science NCERT Solution

NCERT Class 10 Science Chapter 1 Chemical Reaction and Equations Notes for CBSE, HBSE and Other Boards Solution.

## Chemical Reaction and Equations Class 10 Science Notes

Chemical Reactions and Equations

There are certain changes which occur when a chemical reaction takes places. These are as follow:

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

Chemical Equations

In chemical equations, the substance that undergo chemical change in the reaction is called reactants. The new substance formed is called product.

Magnesium + Oxygen → Magnesium oxide

Mg + O2 → MgO

In this chemical equation magnesium and oxygen are reactants, while magnesium oxide is product formed.

Balanced Chemical Equations

In a balanced chemical equations the number of atoms in each side either in reactant or product must be equal. This equality of atoms in chemical equations  is called balanced chemical equations.

Eg. Fe + H2O  →  Fe3O4 + H2

In the given chemical equation first we check Fe i.e in LHS is 1 and in RHS is 3. Therefore we multiply fe by 3.

3Fe + H2O  →  Fe3O4 + H2

Now check O i.e in LHS is 1 and in RHS is 4. Therefore multiply H2O by 4.

3Fe + 4H2O →  Fe3O4 + H2

Now Iron and oxygen are balanced. Its turn to balance hydrogen. Now, Hydrogen atom in LHS is 8 and in RHS is 2. Therefore multiply H2 by 4.

3Fe + 4H2O G → Fe3O4 +4 H2

Therefore balanced equation is 3 Fe + 4H2O →  Fe3O4 + 4H2.

Types of Chemical Reactions

There are several types of Reactions. Some important of them are as :

1. Combination Reaction

In this type of reaction two or more reactants are combined to form a single product.

Eg. CaO + H2O →  Ca(OH)2 + Heat

In the given example calcium oxide and water combine to form a single product, calcium hydroxide.

2. Decomposition Reaction

In this type of reaction single reactant is breaks down to two or more simpler products.

Eg. CaCO→ CaO + CO2. In this given example calcium carbonate is decomposed to calcium oxide and carbon dioxide on heating. When a decomposition reaction is carried out by heating, it is called thermal decomposition.

2AgBr → 2Ag(s) + Br(g) This reaction is used in black and white photography.

3. Displacement Reaction

It is a type of reaction in which a more active element displaces less active element.

Eg. Zn + CuSO4 → ZnSO4 + Cu. In this example zinc displaces copper from copper sulphate solution as zinc is more reactive than copper.

4. Double Displacement Reaction

In this type of reaction two elements displaces each other from their respective solutions.

Eg. Na2SO4 + BaCl2 → Ba SO4 + 2NaCl

5. Oxidation and Reduction

If a substance gains oxygen during a reaction, it is said to be oxidised and if a substance loses oxygen during a reaction, it is called reduced.

Therefore, A reaction in which one reactant gets oxidised is called oxidation reaction and a reaction in which one reactant gets reduced is called Reduction Reaction. When both of them combined is called Oxidation-Reduction reactions.

Eg. CuO + H2 → Cu + H2O . In this example copper oxide is losing oxygen and is reduced. The hydrogen is gaining oxygen and is being oxidised.

Corrosion

It is a process in which decay of elements takes place in the presence of moisture, air and water. When iron is decayed in presence of these conditions then it is called rusting of iron. The colour of rusting of iron is reddish brown while black coating on silver and green coating on copper are other examples of corrosion.

Rancidity

It is the process in which fat/oil containing food materials  become rancid and their taste and smell changes in the presence of oxygen. This happens because these items gets oxidised. To prevent them from oxidation antioxidants are added to food items. Chips manufacturers uses nitrogen gas in their chips packets to prevent from oxidation.

Exothermic Reaction

A reaction in which heat energy is released along with the formation of products is called exothermic  chemical reactions.

Eg. (a) Burning of natural gas. (b) decomposition of vegetable matter into compost. (c) Respiration is also exothermic process.

Important Chemical Formula and Their Names

1. Quick lime or Calcium oxide = CaO

2. Slaked lime or Calcium hydroxide = Ca(OH)2

3. Limestone or Calcium carbonate = CaCO3

4. AgBr = Silver bromide.

5. FeSO4 = Ferrous sulphate.

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