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प्रश्न
The rusting of an iron object is called :
विकल्प
corrosion and it is a physical as well as a chemical change
dissolution and it is a physical change
corrosion and it is a chemical change
dissolution and it is a chemical change
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उत्तर
corrosion and it is a chemical change
Rusting of iron takes place in the presence of air (O2) and water vapour. Action of air and moisture on iron converts it to its oxide. This process is called corrosion and it leads to the formation of a new compound. Therefore, it is a chemical change.
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संबंधित प्रश्न
Tick the most appropriate answer.
5. Photosynthesis requires
- heat energy.
- wind energy
- sunlight.
- sound energy
Fill in the blank.
An earthquake is a .................. change.
Write true or false
Melting of ice is a physical change.
Write true or false
Burning of sugar is a temporary change.
Solve this crossword by using the clues that follow-
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1 . It is the change that takes place in case of swinging pendulum of a clock. –
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change.
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Fill in the blanks with the appropriate words of the statement given below:
Heating a piece of iron is considered a __________ change while heating a piece of coal [carbon] is considered a ___________ change.
Compare the energy changes involved during a physical and a chemical change.
Select the chemical changes from the following list of changes
Preparation of carbon dioxide from calcium carbonate & dilute hydrochloric acid.
When a woolen yarn is knitted to get a sweater, the change can be classified as ____________.
