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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
State whether the following is physical or chemical changes.
Slaking of lime —
Write true or false
Cutting of paper into pieces is a chemical change.
Write true or false
Deforestation is a man-made change.
Which of the following are physical changes and which are chemical changes?
Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Fill in the blank with the appropriate word of the statement given below:
If a change is permanent and irreversible it is considered a _________ change.
Give four reasons why the burning of a magnesium ribbon in the air is considered a chemical change.
Sublimation of Iodine is a ______.
Classify the following as physical or chemical properties
The composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements.
Give two examples for the following case:
Physical changes which are not reversible
