Why are boiling and melting examples of physical changes?

Answer 1

You know if it's a chemical chagewhen two or more of the following have happened:

1. a precipitate has formed(bubbles)

2. heat is absorbed or released

3. there is a change in odor

4. there is a change in colour

5. the change is diffiult to reverse

6. starting material is used up

7. a material with new properties is formed

A physical change may only be a change in state and the change should be easy to reverse

Answer 2

A physical change is when the object changes shape, color, or physical state.

Answer 3

The physical and chemical properties, and chemical composition, are not changed after a physical change.

Answer 4

The process can be easily reversed by evaporating the water.

Answer 5

a physical change is when there are no new substances made and it is easy to reverse, a chemical change is when there is a new substance made and it is not easy to reverse

Answer 6

Boiling and melting are examples of physical changes because when you boil water, it's still water. When you melt chocolate, it's still chocolate. Therefore they have not chemically changed.

Answer 7

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