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प्रश्न
Chemical changes are accompanied by changes in energy.
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उत्तर
In a chemical change, molecules and atoms rearrange themselves to form new substances. This rearrangement involves some energy changes. It can either be absorption or evolution of energy.
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संबंधित प्रश्न
What do you observe when :
a piece of paper is burnt
Fill in the blank
Burning of fuel is a _______ change.
Tick (√) the correct alternative from the choice given for the following statement
Burning is a
True or false?
In a chemical change, rearrangement of molecules and atoms involves some energy changes.
Melting of solid (wax) is a physical change.
Under which different types can the following changes be classified?
Conversion of milk into yoghurt.
Give reason.
While purchasing canned food, its expiry date should be checked.
Give reason.
A dry handkerchief gets wet at once on dipping in water, but it takes longer for a wet handkerchief to dry.
Explain in brief the involvement of energy in physical and chemical changes.
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?
