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प्रश्न
Change is the law of nature which occurs in everyday life.
State when a substance [i.e. matter] undergoes a kind of change.
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उत्तर
Change is the law of nature that occurs in everyday life. A substance [i.e. matter] undergoes a kind of change when subjected to energy changes.
The matter is said to undergo certain changes when energy is added to the matter or removed from the matter.
Examples of Changes are:
- Ice melts on supplying heat to it.
- Milk changes into curd when a little curd is added to hot milk.
APPEARS IN
संबंधित प्रश्न
A physical change is temporary. Explain.
State four differences between physical and chemical changes.
Tick (√) the correct alternative from the choice given for the following statement.
A substance which can not sublime is
Classify the following as a physical or a chemical change.
Manufacture of salt from sea water
Fill in the blank.
The process of a liquid changing into a solid is called ________
Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight.
State the conclusions which can be drawn, to represent photosynthesis as a physical or a chemical change.
Give reasons why – separation of mixtures e.g. iron from a mixture of iron and sulphur is a physical change, but heating a mixture of iron and sulphur is considered a chemical change.
State which of the following terms connected with change of state of matter i.e.
(a) Melting
(b) Vaporisation
(c) Condensation
(d) Freezing
pertain to –
- Conversion of a liquid into a vapour or gas.
- Conversion of a liquid into a solid.
- Conversion of a solid into a liquid on heating.
Classify the following changes as physical and chemical changes
A rough piece of wood is sanded and polished resulting in change in texture, Rusting of a iron nail, Painting the grill, Bending a paper clip, Pounding silver into thin plate, Rolling the chappathi dough into thin wire, Occurrence of day and night, eruption of volcano, burning of matchstick, dosa from the batter, blinking of eyelids, occurrence of a thunderstorm, rotation of the earth, formation of eclipses.
| Sr. No. | Physical changes | Chemical changes |
| 1. | ||
| 2. |
Tearing of sheet of paper into pieces is ______ By the process of Heating of water, change.
