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प्रश्न
What role does energy play in initiating a chemical change ?
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उत्तर
In a chemical change molecules and atoms rearrange themselves to form new substances. This process involves some energy changes. In some changes energy is absorbed
e. g. burning of a substance and in some cases energy is evolved e.g. photosynthesis
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संबंधित प्रश्न
What do you observe when :
a piece of paper is burnt
State whether the following is physical or chemical changes.
Melting of wax —
State whether the following is physical or chemical changes.
Boiling of an egg —
Tick (√) the correct alternative from the choice given for the following statement
Burning is a
Tick (√) the correct alternative from the choice given for the following statement
When sugar is heated, its colour changes into
Fill in the blank
An earthquake is a _______ change.
Give reason.
While purchasing canned food, its expiry date should be checked.
Observe the picture containing a kettle and note that it has salt water in it and answer the following questions:
- What is name of the process that is done to the kettle?
- What will happen to the content of the kettle?
- What kind of change is occurring on the cold surface of the metal plate?
- What can you say about the quality of water that is obtained in the beaker?
Paper, LPG, CNG petrol, etc, are ______ substances.
Cut vegetables turn brown when exposed to air, this is due to ______.
