First, note that this course assumes that you have also taken Intro: Reactions and Rates (also on Coursera, from the same professor). In the video lectures, she references things covered in that course, and many of the quiz/final exam questions test material from that course which was not covered in this one. But both classes are so easy that you could finish both of them in about a week even while working full time.
Despite being offered by Duke University, this is not a college level course. For reference, I have a bachelor's degree in physics and astronomy, so I know the level of rigor in university level science courses. This material is more suitable for junior high students as the most 'advanced' math actually used in the course is ratios (and one honors problem that needed algebra). Coursera's "Advanced Chemistry" (aimed at high school students) is closer to the desired level of material, but EdX is a better platform for actual college level courses - I'm now doing General Chemistry 1 from MIT through EdX.
Furthermore, you can't really learn chemistry without advanced math. So this course is more 'talking about chemistry ideas' than it is 'doing chemistry.' In the 'quantum mechanics' (QM) unit , the professor acknowledges that you can't actually do QM without calculus. (As a physicist, I've actually taken courses on QM; but since they aren't taken until junior year, and the calculus sequence is finished during freshman year, this poses no problem. It's only Coursera which assumes its students don't know anything.) Further, you can't really call what the professor teaches here QM - my Introduction to Quantum Mechanics course was 100x more advanced than this.
On that note, at least half of the material covered in this "chemistry" course is actually physics: wave-particle duality of light, wave-particle duality of electrons, phase changes, gas laws, pseudo quantum mechanics. It is also concerning that some of the physics in this course doesn't match the physics I learned in physics courses. For example, the definition of the constant k (in Coulomb's Law) includes ε, so I don't know why both k and ε appear in the form of the equation given in this course. Similarly, the symbols used for and the names given to the quantum numbers in this course are different from the names and symbols what we actually use in QM.
Pedagogically, the order of presentation in this course should be changed. The professor uses concepts before they have been introduced, which prompted me to look up the material on other websites (chem.libretexts is a great source). For some of the lessons, I found it easier to take notes from another source before glancing through the video lecture. It is also pedagogically unsound to provide 0 feedback on the quizzes and exams. Without knowing what the correct answer should have been, and ideally how to find that answer, students don't learn from practice problems. Furthermore, many of the quizzes mark the correct answer as incorrect. Some of these errors could be because the professor sometimes rounds the constants used in the equations and sometimes doesn't, meaning that you don't know which version was used in the 'correct' answer on the quiz. (Ex: sometimes the atomic mass of oxygen is 15.999 and sometimes it's 16; sometimes K = C + 273 and sometimes K = C + 273.15. On the multiple choice final exam, it was easy to find the answer closest to mine, but the quizzes were fill in the blank). Other times whoever edited the quizzes didn't notice that the correct answer isn't provided. (Ex: on the final exam, several questions were identical to questions we had already solved in the Week 5 and Week 6 quizzes. The correct answer for one such problem, as shown by the fact that I got it right on the quiz, wasn't even provided as a multiple choice answer on the final).
Overall, part I of this course (Rates and Ratios) is suitable for junior high students wishing to start studying chemistry early, but middle schoolers will likely need help from a knowledgeable adult due to the out-of-order presentation of material in part II of this course (Structures and Solutions). Students with a background in science can cover this course in about a week and then move on to an actual college class. But there's no reason to waste money on the certificate for this course given that even a community college course would have more academic standing than this. High school students should instead take AP Chemistry, which will give them actual college credit and adult students are advised to take courses from an actual university or through EdX.