it depends on ehat kind of sentence it is in for example She scratched the her phone. (scratched a verb) in the sentence: He out the scrathed pocket in his pocket. (scratched is an adjective)
the smell of carrots :D
tectonic
A bump.
Verb
Unscratchable? I am not sure if that is the kind of word that you are looking for...
Copper.
Freesia
Ponderosa Pine
Artificial smells are made just like any fake smell, with chemicals or some kind of extract. I hope this was useful!
Chemical change
a snake sandwich