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प्रश्न
Define a chemical change. Give two examples of the above changes.
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उत्तर
A permanent change in which new substances are formed whose composition and properties are completely different from those of the original
substances.
Chemical change:
(i) Burning of wood.
(ii) Breathing.
संबंधित प्रश्न
Classify the following as chemical or physical change:
Boiling of water to form steam.
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
Choose the most appropriate answer.
Rising and setting of the sun at a given place is a
Tick the most appropriate answer.
3. Physical changes are
- permanent.
- periodic,
- temporary
- irreversible.
Fill in the blank
change in which the substance can be brought back to its original state is called a ............... change.
State three differences between evaporation and boiling
Write true or false
Melting of ice is a physical change.
True or false
Dissolving of a solid in liquid is a physical change.
Write true or false
Dissolving of solute in a solvent and rusting of iron are both physical changes.
What will you take into account while identifying the following?
A chemical change in a substance.
Differentiate between a physical change and a chemical change with reference to – Nature of change is temporary and reversible or permanent and irreversible.
State whether the following statement is true or false. If false write the correct statement.
Melting of ice is an exothermic, irreversible chemical change.
Fill in the blank with the correct word of the statement given below:
Sublimation involves a __________ change.
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 matter is added or removed during a ____________ change.
Natural changes which take place in nature on their own, are beyond the control of human being.
Analogy:
Melting of ice: Physical change.
Popping of popcorn: ______.
Mention a few physical properties of a substance.
Give an example to justify the statement that physical changes can be reversible as well as irreversible.
