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प्रश्न
Classify the following as a physical or a chemical change.
Burning of paper
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उत्तर
Chemical change
APPEARS IN
संबंधित प्रश्न
Changes in which only ______ properties of a substance change are called physical changes.
Chemical changes are accompanied by changes in energy.
What role does energy play in initiating a chemical change ?
Make a list of different types of changes with example.
Give two examples of periodic changes.
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.
Which of the following are physical changes and which are chemical changes ?
Glowing of an electric bulb
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.
Water is the universal solvent. Why?
Mention some of the different conditions needed for chemical changes to occur.
