Answer:
Teenage girls are pros at creating me. Learn me in classes.
Part carbon part water I am poison to the fishes. Many falsely claim my name I am the pause that refreshes.
In many hall ways you would stand if not with me in hand.
I cannot be felt, seen or touched. Yet I can be found in everybody. My existence is always in debate, yet I have my own style of music. What am I?
I am a portal to another world which you cannot enter. Only you can see me but I can't see you.
When is it bad luck to see a black cat?