Question

what is the difference between chemical and physical reactions?

Answer 1

There are several differences betweena physical and chemical change in matter or substances. A physical change in a substance doesn't changewhat the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.ok

Answer 2

BASIS FOR COMPARISONPHYSICAL CHANGECHEMICAL CHANGEMeaningPhysical change refers to a change in which the molecules are rearranged but their internal composition remains same.Chemical Change is a process in which the substance transforms into a new substance, having different chemical composition.ExampleTearing of paper, melting/freezing of water, cutting of trees, etc.Burning of wood/trees/paper, rusting of iron, setting of curd, etc.NatureReversibleIrreversibleOriginal matterCan be recoveredCannot be recoveredInvolvesChange in physical properties of the substance, i.e. shape, size, color etc.Change in chemical properties and composition of the substance.Product FormationNo new product is formed.New product is formed.EnergyAbsorption and evolution of energy do not take place.Absorption and evolution of energy take place, during reaction.