Question

each sketch is drawn as if the sample were under a microscope so powerful that individual atoms could be seen. also, you entire sample, and that the sample is in a sealed box, so that no matter can enter or leave.

Explanation:

Change 1

Step1: Analyze particles

Original substance has one - type particles. After change, new particles (with different composition) are formed.

Step2: Determine change type

Since new substances (new particle types) are formed, it is a chemical change.

Change 2

Step1: Analyze particles

Original substance has one - type particles. After change, same - type particles (but arranged differently).

Step2: Determine change type

No new substances (particle composition remains same) are formed, so it is a physical change.

Change 3

Step1: Analyze particle count

Original sample has more particles (in terms of number of units) than after the change. But the sample is in a sealed box (matter can't enter or leave).

Step2: Determine possibility

Since matter conservation is violated (particle number change without matter exchange), it is impossible.

Answer:

Change 1: a chemical change; Change 2: a physical change; Change 3: impossible.