(a) State two differences between a physical change and a chemical change. (b) Complete the table by giving the name of the process of change and the type of change, 'chemical' or 'physical'. | Change | Name of Process | Is it Physical or Chemical Change? | |---|---|---| | (i) Dry carbon dioxide changes into vapour | | | | (ii) Burning of magnesium in the air | | | | (iii) Sugar added into a beaker of water | | | | (iv) Sugar gives rise to carbon and water vapour upon heating | | | | (v) Burning a piece of paper | | |
Answer (2)
A physical change affects only the physical properties of a substance while a chemical change alters its chemical composition and creates new substances. The table provided includes processes like sublimation and combustion, indicating whether each is a physical or chemical change. Understanding these changes helps clarify the nature of substances and their transformations.
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(a) Differences between a physical change and a chemical change:
A physical change is a change in which the form of matter is altered, but one substance is not transformed into another. Physical changes usually affect the form, phase, or appearance of a substance without changing its composition. For example, melting ice into water is a physical change because it's still water in a different state.
A chemical change results in the formation of one or more new substances with different chemical properties. This type of change involves making or breaking chemical bonds. For example, rusting of iron is a chemical change because it results in the formation of iron oxide, a new substance.
(b) Completing the table:
ChangeName of ProcessIs it Physical or Chemical Change?(i) Dry carbon dioxide changes into vapourSublimationPhysical Change(ii) Burning of magnesium in the airCombustionChemical Change(iii) Sugar added into a beaker of waterDissolutionPhysical Change(iv) Sugar gives rise to carbon and water vapour upon heatingDecompositionChemical Change(v) Burning a piece of paperCombustionChemical Change
