my teacher in high school chemistry or physics told us cutting a piece of paper was a physical, not a chemical change (the textbook spent a lot of time differentiating those). It wasn't until many years later that I learned that cutting paper breaks hydrogen bonds. H-bonds are neither covalent nor ionic, but more like in-between (partial sharing of electron density by two different nuclei) but can be modelling (approximately) using ionic models (partial charges separated by a distance).

Is breaking an h-bond physical, not chemical? I want to talk to my teacher.