you can say they are synonyms, but chance can be a noun, a verb and an adjective while opportunity is a noun. the weekend is an opportunity to rest and have fun. don't miss this chance. i'mnot willing to chance this job. it's a chance result. but we say: i found this amazing book by chance(not by opportunity).

They are synonyms. However, opportunity tends to be more formal. In some cases only one of the words can be used: I won't give him a second chance. (not opportunity) job opportunities (not chances) equal opprtunities (not chances)

yes, that's what i mean. so could you tell me what is the difference?? :D

you mean: what is the difference between chance and opportunity?