# Do atoms/molecules change their arrangement during a physical change?

Mar 16, 2016

During a physical change atoms WITHIN a molecule do NOT change their arrangement. Molecules may change there arrangement compared to other molecules.

#### Explanation:

A physical change does not involve the forming or breaking of any bonds within a molecule. So for example, water boiling is a physical change. $\text{H"_2"O}$ molecules remain exactly $\text{H"_2"O}$ through this process. If a hydrogen or oxygen were removed or added from a water molecule then it would be considered a chemical change.

The water molecules do, however, get farther apart. This means that two waters which were right next to each in the liquid may be very far apart from each other in the gas phase (after boiling)

Compare this to a chemical change, say rusting. In this case you have iron forming bonds with oxygen. So oxygen used to be separate from iron, but after they change they will be glued together by chemical bonds.

Does this help?