Chemical Reactions and Equations Notes for Class 10 Science
Following are Chemical Reactions and Equations Notes for Class 10 Science. These revision notes have been prepared by expert teachers of Class 10 Science as per the latest NCERT, CBSE, KVS books released for the current academic year. Students should go through Chapter 1 Chemical Reactions and Equations concepts and notes as these will help you to revise all important topics and help you to score more marks. We have provided Class 10 Science notes for all chapters in your book. You can access it all free and download Pdf.
Chapter 1 Chemical Reactions and Equations Notes Class 10 Science
1. During chemical reactions, chemical composition of substances changes or new substances are formed.
2. Chemical reactions can be written in chemical equation form which should be always balanced.
3. Types of Chemical Reactions
4. (i) exothermicreaction: A chemical reaction in which heat energy is evolved.
C + O2 →CO2 (g) + heat
(ii) Endothermic reaction: A chemical reaction in which heat energy is absorbed.
ZnCO3 + Heat →ZnO + CO2
5. Redox reaction: Chemical reaction in which both oxidation and reduction take place simultaneously.
Oxidation: Reaction that involves the gain of oxygen or loss of hydrogen.
Reduction: Reaction that shows the loss of oxygen or gain of hydrogen
ZnO + C →Zn + CO
ZnOis reduced to Zn -reduction
C is oxidized to CO —– oxidation
6. Effects of oxidation reactions in our daily life:
(a) Corrosion: It is an undesirable change that occurs in metals, when they are attacked by moisture, air, acids and bases.
Corrosion (rusting) of iron: Fe2O3. xH2O (Hydrated iron oxide)
Corrosion of copper: CuCO3.Cu (OH) 2 (Basic copper carbonate)
Corrosion of silver: Ag2S (Silver sulphide)
Corrosion of Aluminum: Al2O3(Aluminum oxide)
(b) Rancidity: Undesirable change that takes place in oil containing food items due to the oxidation of fatty acids.
(1)Adding antioxidants to the food materials.
(2) Storing food in air tight container
(3) Flushing out air with nitrogen gas.