Physical change

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A physical change involves the change just in the physical body of the substance without changing its composition. Chemical change does the change within the composition of the substance, as the result of chemical change new substance is produced. Indications that a chemical change took place are: bubbles, heat gained or released, color change, precipitation is formed.

Another way in which the distinction between chemical and physical changes is often expressed is to state that only chemical reactions involve the rearrangement of atoms within the molecule, which leads to the creation of a new molecule (new substance). Physical change does not create anything new, no change in the identity of the material (substance).

[edit] Examples

Examples of physical changes include:

• Change of state (such as solid to liquid)
• Creation or separation of a mixture (including homogeneous mixtures, where the solute may not be visible)
• Physical deformation (cutting, denting, stretching, etc.)
• Physical relocation (moving an object)

Some expanded examples of physical and chemical changes:

• If a piece of paper is cut up into small pieces, it is still paper. The substance remains the same, while its shape has been physically changed. This is a physical change in the shape and size of the paper. If the same piece of paper is burned, the substance (matter) from which paper was made undergoes a chemical change, gains new properties, and looses old ones (becomes an absolutely new substance: ash). Burning is a chemical change called combustion.

• You can try to mix sugar with water to dissolve sugar in the water, this would be a physical because even though water dissolves suger, it does not change what it is, it still has the same properties. The water could be evaporated and sugar crystals would reappear. However, if one baked a cake with flour, water, sugar, and other ingredients, new substances would appear. Chemical reactions occur in the baking process, and the changes are chemical changes.