24. what is a chemical reaction?

answer: a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

explanation:

a result in which two substances are combined

explanation:

when you put two different chemicals together they sometimes don't agree on each other or say, they don't see eye to eye so they start doing separate things to get way from each other and when this happens they cause a reaction. hope this : )

cramming before a final is bad because it makes a student's stress level higher. students who embrace cramming to get through a final exam week find themselves struggling to perform consistently, once the brain adjusts to prolonged sleep deprivation.