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प्रश्न
Explain the term – ‘sublimation’. Is sublimation of naphthalene – a physical or a chemical change. Give reasons.
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उत्तर
It is the conversion of a solid – directly into gaseous (vapour) state and on cooling directly back to solid-state – without changing into a liquid state.
It involves a change of state-and hence it is a physical change.
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संबंधित प्रश्न
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
Fill in the blank.
Changes that occur in nature are called ........................
Write true or false
Burning of paper and formation of curd are reversible changes.
Classify the following as physical or chemical changes :
Breaking of a glass tumbler
Given reason:
Freezing of water to ice and evaporation of water are physical changes.
Differentiate between a physical change and a chemical change with reference to – Formation of products.
Fill in the blank with the correct word of the statement given below:
Sublimation involves a __________ change.
Give the reason why the following is considered as chemical changes.
Sulphur when burnt in air evolves a gaseous acidic product.
Filling up a balloon with hot air is a _______ change.
State whether the following statement is true or false:
Stretching of rubber bands is not a physical change.
