You find a nail on the ground in the parking lot, in a small puddle of water. rust has formed on the outside of the nail. was this a physical or chemical change? explain

Something with rust means that it has oxidized which is a chemical change. The reason it is a chemical change is because the iron had a chemical reaction with the oxygen and water which resulted in the creation of a new compound (that is a chemical change). You can't change the nail to not having any rust form because the rust will still exist ( If you clean it the rust will still be there but on another object )

Temperature and pressure