tPOL Topics in Chemistry

You can find a complete list of chemistry topics organized by project using this link.
tPOL topics list
You should be prepared to demonstrate a thorough understanding of concepts related to any project. Some of the projects overlap and that is indicated on the topics list. For example, you should have an understanding of 3D molecular structure if you plan on discussing concepts related to the Ethics of Science project. Most of the concepts in chemistry have fundamental building blocks (the mole, protons/neutrons, etc.. These concepts are implied in the third bullet point on your tPOL rubric.
Choose a project based on what you are drawn most to rather than which projects appears to have the fewest topics to cover.