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प्रश्न
Match the columns.
| Column A | Column B |
| 1. a change which cannot be easily reversed | a. man-made change |
| 2 a change that repeats itself at regular intervals | b. chemical chang |
| 3. a change that is made by humans | c. physical change |
| 4. a change in which the original substance cannot be obtained | d. periodic change |
| 5. a change where no new substance is formed | e. irreversible change |
| f . slow change |
उत्तर
| Column A | Column B |
| 1. a change which cannot be easily reversed | e. irreversible change |
| 2 a change that repeats itself at regular intervals | d. periodic change |
| 3. a change that is made by humans | a. man-made change |
| 4. a change in which the original substance cannot be obtained | b. chemical chang |
| 5. a change where no new substance is formed | c. physical change |
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Boiling of water to form steam.
True or false
Dissolving of a solid in liquid is a physical change.
Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct ?
- P is a compound
- X and Y are compounds
- X and Y are elements
- P has a fixed composition
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
Glowing of an electric bulb.
Select the correct answer from the choice given below to complete the sentence
The energy required for completion of a physical change is ______________ when the change is reversed.
Natural changes which take place in nature on their own, are beyond the control of human being.
A physical change is generally____________.
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?
Adding sugar to milk is a physical change.
