The observation that most likely indicates that only a chemical change has taken place is that the change cannot be reversed.
There are two types of change which matter undergoes;
- Physical change
- Chemical change
A chemical change leads to the formation of a new substance so it is usually irreversible.
On the other hand, a physical change is easily reversible. It often involves a change in shape, form or appearance of matter.
If a change is cannot be reversed, it is most likely a chemical change.
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