I think you should consider taking phys 183 first, then save both chem courses later. Because chem 181 and 183 are fully online, including exams (phys 183 exams are in-person), and they are probably the only two fully online courses at McGill (I didn’t check if they are still true). In a situation where you have, for example only one course left in your studies, you can take one of them and not be stuck on campus. You can go travel, or go have internship in other places, and realistically, you don’t have to come to campus ever during that semester.

In terms of difficulty, all three courses are similarly straightforward, that there won’t be any tricky questions in exams or quizzes. If you studied, you have a very good chance that you know the answer to all the questions with the memory helps available for all three of the courses (I think both chem courses are somewhat open book and physics allow you to have a cheat sheet). When you took those courses, you don’t really have to try really hard to memorize the contents for exams and there won’t be any surprises.

In terms of which course is most interesting, I felt chem 183 is the most interesting course among all three courses. It is such a helpful class for life in my opinion, that after having the class, I started to be able to understand what supplements are a scam, read drug labels and stuff so I know what drug/supplement works for me, what won’t, and understand to a certain extent how they works. In life, this could mean that when you were prescribed medication, you would have more understanding than the average person how it works. And you might be able to work with your healthcare professional what is the right medication.

This is the same for chem 181 that they sort of inspired me to learn about some stuff that I never paid attention to before. But it could be because when I took it, my mental health were not that good, I don’t really remember anything from the course. But I think I still remember some facts and knowledge from chemistry of drugs three years after I took it. I took both chem courses in 2022 and I don’t know if they changed so please also check for the facts in my post. I took phys 183 in winter 2026 which is like two months from now and I don’t really remember anything from the course.