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प्रश्न
Name the following:
The term involved in the change of state from – ‘water to ice’ – which is a physical change.
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उत्तर
Freezing Point.
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संबंधित प्रश्न
Classify the changes involved in the following process as physical or chemical changes:
Photosynthesis
Choose the most appropriate answer.
Rising and setting of the sun at a given place is a
Give the main differences between physical changes and chemical changes.
Fill in the blank.
There is no change in the _____________of the substance during a physical change.
Differentiate between a physical change and a chemical change with reference to – Formation of products.
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.
A change in which matter undergoes a change but the total mass of the substance is unaltered is a ______ change.
Two drops of dilute sulphuric acid were added to 1 g of copper sulphate powder and then small amount of hot water was added to dissolve it (step I). On cooling, beautiful blue coloured crystals got separated (step II). Step I and Step II are:
Cutting a log of wood into pieces is a chemical change.
