Question

Water is made of two hydrogen atoms and one oxygen atom bonded together. Julia is describing how water undergoes a physical change when it boils. She says that the particles shift to be farther apart and that the oxygen and hydrogen separate. She also says that the total mass of the steam is the same as the initial water, and that heat energy was required to cause the change. She finishes her description by saying that the steam can be turned back into water if it is cooled.
Which is the mistake in her description?

The total mass remains the same in physical changes.
The arrangement of particles may change in physical changes.
Atoms remain bonded to each other in physical changes.
Energy changes may occur in physical changes.

Answer 1

Answer is: The arrangement of particles may change in physical changes.

If the arrangement of particles is changed, that is chemical change or chemical reaction (new substance is formed).

In physical change, the bonds between oxygen and hydrogen can not  be separated.

Physical property can be observed and measured without any changes in molecular composition. The same substance is present before and after the change.

Answer 2

Atoms remains bounded in physical state ! it does not separate ! she says hydrogen and oxygen separated but this does not happen !