In an exam teacher asked students to give example of a change which is a physical as well as a chemical change? Which one of the following example is correct?
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In an exam teacher asked students to give example of a change which is a physical as well as a chemical change? Which one of the following example is correct?
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The correct option is B Burning of candle
Among the given examples only burning of candle is an example which involves both physical as well as chemical change.It is a physical change because on heating the candle wax melts and it again turns into solid wax on cooling down a little. It is a chemical change because the wax near to the flame on burning gives rise to new substance like carbon dioxide, carbon soot, water vapours, heat and light.
Photosynthesis is a chemical change because in this a new substance is formed and it is irreversible.
Beating of aluminium to make foil and dissolving salt in water is are both physical change because in both the processes no new substance is formed. For instance, aluminium will show the same set of chemical properties even if it has been turned into a foil.
Burning of candle
Among the given examples only burning of candle is an example which involves both physical as well as chemical change.It is a physical change because on heating the candle wax melts and it again turns into solid wax on cooling down a little. It is a chemical change because the wax near to the flame on burning gives rise to new substance like carbon dioxide, carbon soot, water vapours, heat and light.
Photosynthesis is a chemical change because in this a new substance is formed and it is irreversible.
Beating of aluminium to make foil and dissolving salt in water is are both physical change because in both the processes no new substance is formed. For instance, aluminium will show the same set of chemical properties even if it has been turned into a foil.
