I wrote the wrong answers on our chemistry final so that my friend would fail.
How did you write the wrong answers?
I wrote the answers the other way around.
It can be annoying when your friend tries to cheat off your answers, but making them fail on purpose is wrong. If you're friends with someone then you should try to support them however you can. If you don't want them to cheat off of you, then be blunt about it, but don't give them the wrong answers.
Nah, it's okay. My friend is sneaky and doesn't deserve to pass.
I get why you're annoyed, but I still don't think that intentionally writing the wrong answers just to make your friend fail is right. You should have just told them you didn't wan to help them cheat. If they find out what you did they might not want to be your friend anymore.