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प्रश्न
What will you take into account while identifying the following?
A chemical change in a substance.
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उत्तर
Chemical changes are changes that involve the reaction of substances with one another. Such reactions result in alterations in the chemical compositions of the substances involved. These changes lead to the formation of new substances.
Characteristics:
- One or more new substances are formed during a chemical change.
- Most chemical changes cannot be reversed easily.
- The chemical composition of a substance undergoing chemical change does not remain the same.
- A chemical change is always accompanied by a change in energy.
संबंधित प्रश्न
Try segregating the things around you as pure substances or mixtures.
Match the columns
| column A | coulmn B |
| 1. A change which cannot be easily reversed | a. man-made change |
| 2.A change that repeats itself at regular intervals | b. chemical change |
| 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 formade | e. irreversible change |
| f. slow change |
Define physical change. Give two examples for the above changes.
State whether the following is physical or chemical changes.
mixing oil with water —
True or false
Is melting of ice a reversible change?
A physical change is temporary. Explain.
Classify the following as a physical or a chemical change.
Burning of paper
Fill in the blank.
The reaction in which energy is evolved is called
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.
Gas exists in three states as solid, liquid, and gas.
