- Changes can be of two types, physical and chemical.
- Physical changes are changes in the physical properties of substances. No new substances are formed in these changes.These changes may be reversible.
Example: crushing a can, glowing of an electric bulb, tearing of paper, mixing of sand and water.
- Chemical Changes are changes in which the composition and chemical properties of the substance get changed. In chemical changes new substances are produced. This change is permanent and irreversible.
Example: burning of a candle, formation of curd from milk, ripening of fruits.
- · Chemical Reactions in daily life:
- Rusting of Iron: Rusting is the process in which iron turns into iron oxide. It happens when iron comes into contact with water and oxygen. The process is a type of corrosion that occurs easily under natural conditions.
Prevention of Rusting:
(i) By Painting
(ii) By Oiling and greasing
(iii) By Chromium plating
(iv) By Galvanizing
(v) By Alloying
- Cooking of food: Cooking causes breakdown of complex molecules of carbohydrates, fats and proteins into smaller molecules.
It is regarded as a decomposition reaction. Cooked food is easier to digest than uncooked food.
- Decay of Organic Substances: Microorganisms like fungi and bacteria produce enzymes which break down complex organic compounds into smaller substances.
It is also regarded as a decomposition reaction.
- Some substances can be obtained in pure state from their solutions by crystallization.
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CBSE
Class–VII | CHAPTER – 1 Integers | NMMS
Revision Notes à Click
Here
Tracing
Changes Through a Thousand Years | NMMS Revision Notes | Class 7 | Social à Click
Here
New
Kings and Kingdoms | NMMS Revision Notes | Class 7 | Social à Click Here
The
Delhi Sultanate | NMMS Revision Notes | Class 7 Social à Click
Here
The
Mughal Empire | NMMS Revision Notes | Class 7 Social à Click Here
Tribes
Nomads and Settled Communities | NMMS Revision Notes | Class 7 Social à Click
Here
Devotional
Paths to the Divine | NMMS Revision Notes | Class 7 Social à Click
Here
The
Making of Regional Cultures | NMMS Revision Notes | Class 7 Social à Click
Here
Eighteenth
Century Political Formations | NMMS Revision Notes | Class 7 Social à Click
Here
Environment
| NMMS Revision Notes | Class 7 Social à Click
Here
Inside
Our Earth | NMMS Revision Notes | Class 7 Social à Click Here
Our
Changing Earth | NMMS Revision Notes | Class 7 Social à Click Here
Air |
NMMS Revision Notes | Class 7 Social à Click Here
Water
| NMMS Revision Notes | Class 7 Social à Click Here
Human
Environment Interactions the Tropical | NMMS Revison Notes | Class 7 Social à Click
Here
Life
in the Deserts | NMMS Revision Notes | Class 7 Social à Click Here
On
Equality | NMMS Revision Notes | Class 7 Social à Click Here
How
the State Government Works | NMMS Revision Notes | Class 7 Social à Click
Here
Role
of the Government in Health | NMMS Revision Notes | Class 7 Social à Click
Here
Growing
up as Boys and Girls | NMMS Revision Notes | Class 7 Social à Click
Here
Women
Change the World | NMMS Revision Notes | Class 7 Social à Click Here
Understanding
Media | NMMS Revision Notes | Class 7 Social à Click Here
Markets
Around Us | NMMS Revision Notes | Class 7 Social à Click Here
A
Shirt in the Market | NMMS Revision Notes | Class 7 Social à Click Here
Nutrition
in Plants | NMMS Revision Notes | Class 7 Science à Click Here
Nutrition
in Animals | NMMS Revision Notes | Class 7 Science à Click Here
Heat |
NMMS Revision Notes | Class 7 Science à Click
Here
Acids
Bases And Salts | NMMS Revision Notes | Class 7 Science à Click Here
Physical
And Chemical Changes | NMMS Revision Notes | Class 7 Science à Click
Here
Respiration
In Organisms | NMMS Revision Notes | Class 7 Science à Click Here
Transportation
in Animals and Plants | NMMS Revision Notes | Class 7 Science à Click
Here
Force
and Pressure | NMMS Quick Revision Notes
| Class: 8 Physics à
Click Here
Reproduction
In Plants | NMMS Revision Notes | Class 7 Science à Click Here
Motion
And Time | NMMS Revision Notes | Class 7 Science à Click Here
Electric
Current and its Effects | NMMS Revision Notes | Class 7 Science à Click
Here
Light
| NMMS Revision Notes | Class 7 Science à Click Here
Waste
Water Story | NMMS Revision Notes | Class 7 Science à Click Here
How
When and Where | NMMS Revision Notes | Class 8 Social à Click
Here
From
Trade to Territory | NMMS Revision Notes | Class 8 Social à Click Here
Ruling
the Countryside | NMMS Revision Notes | Class 8 Social à Click Here
Tribals
Dikus and Vision of Golden Age | NMMS Revision Notes | Class 8 Social à Click
Here
When
People Rebel | NMMS Revision Notes | Class 8 Social à Click Here
Weavers
Iron Smelters and Factory Owners | NMMS Revision Notes | Class 8 Social à Click
Here
Civilising
the Native Educating the Nation | NMMS Revision Notes | Class 8 Social à Click
Here
Women
Caste and Reform | NMMS Revision Notes | Class 8 Social à Click Here