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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
Classify the following as chemical or physical change:
Melting of butter in a pan
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
A physical change is temporary. Explain.
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
State whether the following is physical or chemical changes.
Slaking of lime —
Tick (√) the correct alternative from the choice given for the following statement
Which one of the following is volatile in nature ?
Name two reversible changes.
Select the chemical changes from the following list of changes
The carbon cycle.
Distinguish physical and chemical changes.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
