A physical change is a change in which no new substance is created. The form of the substance is changed, but the composition of the substance is not. Physical changes may involve a color change, dissolving, a change in texture, a change in temperature, or a change in shape. All phase changes are physical changes. Phase changes involve the addition of or loss of kinetic energy, which causes the molecules of a substance to either move farther apart or come closer together respectively. However, the molecular structure of a substance does not change during a phase change.
A chemical change is a change during which a chemical reaction occurs. Therefore, new substances are created during a chemical change. An odor change, a color change, or the formation of a precipitate is indicative of chemical changes. Temperature changes are indicative of endothermic or exothermic chemical changes. Examples of chemical changes are burning, oxidation, corrosion, and fermentation.
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