- A compound being broken down is a kind of chemical change
- A compound can be chemically separated into the elements that it is made of
- So, a compound can only be separated into the elements by chemical change

- A compound can only be separated into the elements by chemical change
- When two substances together form a compound then those substances cannot be physically separated
- Hence, a compound can only be broken down in chemical change but not physcial changes

Hence, a compound can only be broken down in chemical change but not physcial changes
Question
Which of these are broken down during chemical, but not physical, changes?

Context
- When two substances together form a compound then those substances cannot be physically separated 
- A compound being broken down is a kind of chemical change 
- A compound can be chemically separated into the elements that it is made of