The final grade from the teacher is the overall mark you get over all the work you have done. Chemistry is just one part of the science course. In chemistry you have to learn about each small part of chemistry. Ex: Bohr models, ions, periodic table, and compounds etc..... you get quizs on each one of these. after you learn all of them the teacher would give you a unit test which would consist of everything. this would mostly be your report card final grade, which could range up to emerging-developing-proficent-extending.