![]() Thus, there is not net energy change involved.Į.g. (iii) There is no net gain or loss of energy : The amount of energy required to bring about a physical change is generally equal to the amount of energy required to reverse the change. ![]() ![]() On altering the experimental conditions, the change which gets reversed, is a physical change. The water formed from ice can be changed back to ice by placing it in a freezing mixture (a mixture of ice and common salt). (ii) The change is temporary and reversible : It means the change can be reversed by altering the causes which produce the change.Į.g. Hence melting of ice and freezing of water to form ice are physical changes. Since both ice and liquid water are made up of same water molecules (H2O), no new substance is formed during melting of ice and freezing of water. Melting of ice and freezing of water to form ice: When ice is heated, it melts to form liquid water, conversely, when water is cooled in a refrigerator, it freezes to form ice. (i) Now new or different product is formed : The composition of molecules of the substance remains unaltered.Į.g. All the changes taking place around us can be classified into the following two types:ĭefinition: A change which alters some specific physical property of the matter, like its state, texture, magnetic or electrical conditions or its colour, without causing any change in the composition of its molecules, is called physical change, provided it get reversed, if the cause producing the change is removed.įollowing points need special consideration:
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