Question

define a physical and a chemical change.give an example of each ?
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Answer 1

Answer:

Physical changes are changes that only change the appearance of a substance, not its chemical composition.

Ex - Melting of Ice

Chemical changes are the changes that cause a substance to change into an entire substance with a new chemical formula.

Ex - Burning of a paper

Answer 2

define physical change.

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds. example melting of ice.

Define Chemical change.

Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. example burning of wood.