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Learner Reviews & Feedback for Introduction to Chemistry: Reactions and Ratios by Duke University

1,189 ratings

About the Course

This is an introductory course for students with limited background in chemistry; basic concepts involved in chemical reactions, stoichiometry, the periodic table, periodic trends, nomenclature, and chemical problem solving will be emphasized with the goal of preparing students for further study in chemistry as needed for many science, health, and policy professions....

Top reviews


Sep 4, 2023

The teaching method of Dr. Dorian canelas was very simple and impressive. I have learnt a lot and much enjoyed during the lecture and Practical demonstration. I recommend it to all chemistry learner.


Aug 19, 2020

Thank you Professor Dorian A. Canelas! It made me much more easier to understand the basic principles of chemistry and it builds me a lot of confidence in answering some of the problems in chemistry.

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1 - 25 of 303 Reviews for Introduction to Chemistry: Reactions and Ratios

By Noorali H

Jun 13, 2020

It is a wonderful course for Middle school students. A first course in Chemistry, for the gifted students who will do AP Chemistry. Not suitable for adult learners who need an advanced introduction.


May 23, 2020

What an amazing experience! I totally loved it. Prof. Dorian was an amazing instructor. I would like to thank her very much and also Coursera for bringing such course. It was really helpful for me.

By David P

Feb 6, 2018

Great Beginner Course. There are some parts where there will be frustration, but the forums are helpful. Any type of class involving math and science involves practice and work. Professor is great!

By Yury P

Jun 12, 2017

I would give the course 4.5 stars if I could. The course is a great introduction into Chemistry and I really enjoyed it. Professor explains non-trivial topics in lovely and easy to digest way during first 4 weeks. However, the course shifts gears in weeks 5 and 6 and I had to watch lectures twice to fully understand concepts. Moreover, to solve advanced problem set for week 6, I had to read about Ksp calculation outside. Apart from this inconvenience, the course and professor are great.

By Jeremhy C

Jun 18, 2017

When I entered this course, I wanted to expand my knowledge on the foundations of Chemistry. This course helped me to do that and much more. Through this course, I was challenged enough that I can confidently walk into a Chemistry classroom and ace the pretest. I recommend this for anyone who is trying to get a degree in anything branched off of Chemistry.

By Manaurwar A

Nov 12, 2018

hemistry is the study of matter and energy and the interaction between them. There are many reasons to study chemistry, even if you aren't pursuing a career in science.

Chemistry is everywhere in the world around you! It's in the food you eat, clothes you wear, water you drink, medicines, air, cleaners... you name it

By Roezenn G

Aug 20, 2020

Thank you Professor Dorian A. Canelas! It made me much more easier to understand the basic principles of chemistry and it builds me a lot of confidence in answering some of the problems in chemistry.

By Izabela C

Jul 11, 2019

Excellent course. Although, it was very challenging to me to complete it and I had to repeat some of the videos, I am very happy that I decided to take it. It helped me to repeat my knowledge.

By Deborah Z

Sep 22, 2019

This course was a very good review of the material from general chemistry that it covered. The professor was clear and easy to follow. My only complaint is that the advanced problem sets contain calculations that were not explained in the course and then there was no feedback when you got the questions wrong. It was very difficult to find material that explained how to do the problems. They should take more time because they are more challenging, not because you have to search the internet for how to do the problem.

By Maryjane U

Oct 21, 2016

Some quiz answers were marked wrong when they were correct

By Alicia m

Dec 11, 2021

Although "Introduction to Chemistry: Reactions and Ratios" appears to be offered by Duke University, this is not a college level course. It is far easier than even a first year "Chemistry I" course. For context, I graduated magna cum laude with a bachelors degree in physics, astronomy, and math so I know how rigorous true college level science classes are. This course is far too easy to be helpful; I finished it in a few days rather than 7 weeks. And there was no need to actually listen to the lectures; I just quickly read the transcripts (which have some text-to-speech errors), skipping all of the things that were redundant or obvious due to my physics degree and high school chemistry (which wasn't AP but was still more advanced than this course).

First, the instructor of the course considers algebra "too advanced" so all of the quiz/homework problems which require algebra are in the "honors" track. (Because of this, I recommend this class to my junior high Algebra I students who want a head start on high school). But, as part II of this course, Structures and Solutions, acknowledges, to really talk about electrons, you need the wavefuncion from quantum mechanics, and that requires calculus.

Furthermore, the homework/quiz problems for this course are not pedagogically useful. Until week 6, the problems were all duplicates of problems we had already seen solved many times in class; that doesn't help students to apply their knowledge in new situations. By contrast, week 6 tested concepts which had not been introduced in the course. In addition, the only feedback provided by the quiz is "correct" or "incorrect" for each problem. Without showing the correct answer or explaining why a given answer is wrong, students can't learn effectively from practice. (Also, the quiz has the wrong answer marked correct for 2-3 problems).

I found the "honors" material patronizing. As a teacher, I understand the value of scaffolding to help students learn difficult material. But this material was not difficult, and there was too much scaffolding even for middle school learners. Each assignment consisted of about 5 actual problems subdivided into 20 or so questions. Each problem would first ask "do you understand the terms in this problem." Then it asked you to list all the formulas and/or facts from the periodic table necessary to solve the problem. Then it asked you to state in your own words how you would solve the problem. (Sometimes, the best answer was "do exactly the same thing I did on the previous problem.") Finally, it asked for the answer. Since the quiz was automatically graded, I think it gave you credit for anything you wrote in the 'short answer' type questions. If it had asked you to show your work, and that work had been taken into consideration when grading, then it might have been worthwhile. But since I had already solved the problem on paper, there was no pedagogical value in typing the equations and values I had used into my phone.

In summary, if you are looking for a college level introduction to chemistry, look elsewhere. This material is less advanced than high school chemistry. It's not worth paying for a certificate as the quality of this material is not commensurate with a college course. If you want to do some quick and easy review of your high school chemistry over a weekend, of if you are a middle school student who wants to study chemistry, this course might be right for you.

By WShashini S W

Nov 22, 2021

This is an amazing chemistry course!

This course helped me to develop so many skills such as scientific and numerical skills, excellent analytical skills and meticulous attention to detail and accuracy. Not only that but also this skills created a logical and independent mind. My patience and determination have improved as well. I hope this certificate will be worth and create a rich profile in my CV. This course is really interesting and it will be a good start to students to learn chemistry from the beginning without a basic knowledge. I recommend this course for everyone who is willing to carry out their careers in chemistry.

By dor d

Nov 14, 2020

I enjoyed taking this basic chemistry course. coming to this course with a very limited background in chemistry, i feel like it widened my view of chemistry and it's applications in our everyday life. Prof. Canelas is such a great tutor and i wish i had the opportunity to be her student in Duke! this course makes me wanna "dive" deeper in to the field of science. Highly recommended!

By Capucine P

Sep 6, 2018

This course was very helpful for my understanding of biology and physics related content. It is just the right amount of work to learn in seven weeks, although some tests were significantly harder than others and forced me to work more time on. Thank you very much for offering this course!

By Enosakhare O

May 20, 2018

It was a very good course, and I enjoyed it. It was fun, and I think I learnt quite a lot.

By Louie A D B

Jul 22, 2018

There's so much to learn. Thank you Duke University! Thank you Coursera!

By Jeffrey W B

Jun 19, 2020

Professor explains everything very clearly. Both Coursera and the professor deserve blame for sloppiness throughout the course. Text accompanying the videos was produced by running the audio through speech-to-text software. The output was never proofread, and many confusing errors exist in the text. Dead link on the Resources page; a student identified the problem *2 years ago* in the Forums, but it still hasn't been fixed. Biggest problem--Coursera's interface is amateurish. When will Coursera take a break from raking in fees and put a little effort into upgrading their interface?

By Arkojyoti B

Dec 15, 2020

The professor is superbly unengaging. Her toneless voice while she reads from a teleprompter and her desperate attempts to be funny makes one doze off fast. Her gaps make it so that she doesn't really know what she is doing (might be different n an actual class). This is not story time and you don not have to treat learners like pre-schoolers. Also the advanced question sets are bullshit- just cut to the chase already and go for the answers than giving points for "did you understand the question?". Well if I didn't I would get a wrong answer and know I made a mistake somewhere, so need for you to ask exactly what formulas I'm gonna use.

By Ian S

Apr 17, 2020

Waste of time. Hard to follow. Jumpy. Moves too quickly. Expects you to know the answer before even explaining how to find it. A joke.

By Anubhav T

Jun 5, 2020

waste of time

By Natasha R

Sep 6, 2018

Brilliant! I would hugely recommend this to anybody who wants to dive into the basic concepts of chemistry. I did not take chemistry beyond GCSE level and this course was perfect for refreshing my basic knowledge and building upon it. Dr Canelas is very engaging and charismatic. She does a fantastic job of breaking down difficult concepts and making them clear and easy to follow. Interesting, challenging and fun! Every week felt a little more in-depth and challenging than the last. I will definitely be taking a look at the Structures and Solutions course.

By Arya R K

Jun 8, 2020

I highly recommend this course for those students who find chemistry difficult. This course will indeed help you enhance your conceptual knowledge of Chemistry. Personally speaking, it was of a great help to me to build on my existing knowledge and information level. Furthermore, it makes anyone more inquisitive about the advanced concepts in a similar line. Also needless to say that it helped me in my academic excellence. So, all the Chemistry lovers fasten your belt to unlock the mystery of Chemistry.

By Ionuţ C

Dec 1, 2021

It's been a wonderful experience and it has helped me review my preuniversitary knowledge of chemistry, while also adding some new information. Prof. Canelas explained concepts in a thorough and patient way, so that everything is understood. The tests were not very difficult, but they put me in the situation to make connections between different bits of knowledge and they also helped me exercise my arithmetic skills, as I was making a lot of mistakes through lack of attention. Thank you!

By Vasiliki D M

May 28, 2017

The course was extraordinary. Initially I was overwhelomed by the amount of videos each week had but after all they were perfect for ensuring that the concepts were understood. Professor Canelas is an incredible professor who clearly loves delivering this subject. I thoroughly enjoyed the videos, the homework and everything about this course. I hope she delivers more courses on coursera as I would love to enlist in them. Thank you for this course and for delivering it so masterfully :)