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प्रश्न
Classify the following as a physical or a chemical change.
Manufacture of salt from sea water
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उत्तर
Physical change
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संबंधित प्रश्न
Tick the most appropriate answer.
3. Physical changes are
- permanent.
- periodic,
- temporary
- irreversible.
Ripening of fruits is a desirable change.
Which of the following are physical changes and which are chemical changes ?
Which of the following are physical changes and which are chemical changes ?
Freezing of water
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.
Natural and man-made change.
Ammonium chloride is also a sublimable solid. Give a reason why the sublimation of ammonium chloride involves a physical and a chemical change.
State which of the following pertain to – chemical changes.
- Substance retains its identity.
- The change is permanent.
- No new substance is formed.
- Is easily reversible.
- Produces one or more new substances by a change in its composition.
- The change is temporary.
- The composition and properties of the original substance are not altered.
Potassium chloride is added to water and stirred. A salt solution is obtained, which is then boiled, leaving behind a residue.
- Is the above change physical or chemical?
- Name the residue which remains behind after the salt solution is boiled.
- Is the change reversible or not reversible?
- Are the composition and properties of the original substance altered?
- Give a reason why the above experimentation would not be possible if calcium carbonate was taken in place of potassium chloride.
Select the chemical changes from the following list of changes
Preparation of carbon dioxide from calcium carbonate & dilute hydrochloric acid.
Ice, water and water vapour look different and display different ______ properties but they are ______ the same.
