I've had a teacher who didn't know here subject (Chemistry), and opened the textbook to answer very basic questions that I (merely interested in Chemistry, have

I've had a teacher who didn't know here subject (Chemistry), and opened the textbook to answer very basic questions that I (merely interested in Chemistry, haven't studied it) could have answered without. I was very shocked because in Germany you actually have to a good part of the Chemistry studies at University to be allowed to teach it. I wonder if she forgot it all in the mean time, or if she had gamed the system somehow.