Engineers are responsible for designing and building products. In an interview context, expect to be quizzed on your technical skills, and also evaluated for your ability to work as a part of a team to get things built. The specific questions you are asked will depend on what type of engineering position you are looking for. Try a specific engineering discipline, such as software engineer, electrical engineer, or mechanical engineer.
Did you ever work with chemicals before?
No, but I understand a lot about fluid dynamics.