Which of the following is NOT a example of a chemical change?
A. an egg being cooked
B. a piece of paper being torn
C. a piece of bread being toasted

B. a piece of paper being torn

Explanation:

A chemical change is one that cannot be reversed. This means the original properties of the substance or object cannot be restored.

If you cook a raw egg, it would turn into a boiled egg (or a poached egg, however it is being cooked). The reaction is irreversible, so you cannot turn the cooked egg back into a raw egg - it is basically impossible to 'uncook' an already cooked egg.

When you toast a piece of bread, it turns into toast. You can't 'untoast' it back into bread. The chemical changes have already occurred and cannot be undone.

If you tear a piece of paper, it is still paper. You are only ripping it, not changing anything about it. You could simply tape the torn bit back to the original bit, or glue it - either way, it is still paper and nothing has occurred to drastically change the physical state of it.

Therefore, B is not a chemical change.

the device is called “ rocket engine”

hypothesising or postulating