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प्रश्न
Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.
उत्तर
Melting of wax is a temporary and reversible change on cooling, wax solidifies, and no new product is formed while burning of a candle is a permanent change i.e. products are not convertible, a new substance is formed having different composition & different properties.
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संबंधित प्रश्न
Make a list of different types of changes with example.
Classify the following as a physical or a chemical change.
Drying of wet clothes
Fill in the blank.
The reaction in which energy is evolved is called
Given reason:
Cutting of a cloth piece is a physical change, though it cannot be reversed.
Fill in the blanks with the appropriate words of the statement given below:
Heating a piece of iron is considered a __________ change while heating a piece of coal [carbon] is considered a ___________ change.
Compare the energy changes involved during a physical and a chemical change.
Give a reason why – Addition of zinc nitrate to water is a physical change but, the addition of zinc to dilute nitric acid is a chemical change.
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.
______ is the substance that is dissolved in a solvent.
Water is the universal solvent. Why?
