Chemical changes occur when the chemical composition of a substance changes. Boiling alcohol does not change its chemical composition. The alcohol molecules are still the same molecules after boiling as they were before. The only difference is that they are now in a different state of matter (gas).
Physical changes, on the other hand, are changes in the physical properties of a substance without changing its chemical composition. Boiling alcohol is an example of a physical change because the alcohol molecules are still the same molecules after boiling as they were before. The only difference is that they are now in a different state of matter (gas).
