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प्रश्न
Define a chemical change. Give two examples of the above changes.
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उत्तर
A permanent change in which new substances are formed whose composition and properties are completely different from those of the original
substances.
Chemical change:
(i) Burning of wood.
(ii) Breathing.
संबंधित प्रश्न
Classify the following as chemical or physical change:
Burning of paper and wood
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
State three differences between evaporation and boiling
State whether the following is physical or chemical changes.
cutting wood into small pieces —
Write true or false
Cutting of paper into pieces is a chemical change.
Write true or false
Burning of sugar is a temporary change.
Tick the most appropriate answer.
Photosynthesis requires
Fill in the blank
Changes that occur in nature are called ______
Change is the law of nature and occurs in our everyday life, at all times and in all places. Differentiate between the following change with a suitable example.
Desirable and undesirable change.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Periodic and non-periodic change
Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.
Name the following:
The term involved in the change of state from – ‘water to ice’ – which is a physical change.
Compare the energy changes involved during a physical and a chemical change.
Select the chemical changes from the following list of changes
Respiration in mammals.
Select the chemical changes from the following list of changes
The carbon cycle.
When ice melts to form water, change occurs in its
Stretching gold coin into a ring is a ______ change.
Sublimation of Iodine is a ______.
State whether the following statement is true or false:
Anaerobic bacteria digest animal waste and produce biogas.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think rust is different from iron?
