I guess I just don't understand feminine v. masculine if words end in -ao. Are they always feminine?
not always, but most of the time. like the word "perdão" is masculine.
One rule is that words which end in "tion" in English are feminine in Portuguese.
If I'm not mistaken, the vast majority of words ending in '-ão' conform to the following rules regarding gender: if the ending is '-ção' or '-são', it's feminine; otherwise it's masculine.