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

1,119 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


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.


Jun 12, 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.

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251 - 275 of 290 Reviews for Introduction to Chemistry: Reactions and Ratios

By Gyanendra

Jun 4, 2017


By ranjitha r

Jan 7, 2021


By M Z U M

Sep 26, 2020


By Simonas M

Sep 26, 2020


By Dr. M B

May 10, 2020


By Brenno F D S S

May 10, 2021


By Uri S

Apr 18, 2022


By Safira r

Aug 30, 2022


By Carlo T

Nov 16, 2020

Overall, the course is a very good introductory course. There are many great theoretical exercises and real-life examples to their discussions. I also like how they simplified the mole concept into an easily digestible one. However, at times, the course gives examples that students that are not yet acquainted with chemistry may have a hard time processing. It also discusses some concepts that are tied to some chemistry concepts that the course decided not to dabble with, e.g., using examples to show Lewis electron-dot notation and electron pairs but not thoroughly discussing how that works. Because of this, I would not recommend this to students that don't have any idea about chemistry, or to those that hadn't learned it in their secondary schools.

By Josh F

Nov 17, 2019

On the whole this course was worth my time. I had never taken a chemistry class and I was looking for a course to prepare me for other science courses that required a background in basic chemistry. I found the course very easy and quick. All concepts were well explained, except those in week 6, where a plethora of new and basically unexplained notation (Lewis Dot models, chemical structure diagrams) made the lectures harder to follow. I expect that I will learn more about that notation in the second course.

By nijitha k

Sep 12, 2020

It was a wonderful experience. All lectures were excellent. Simple and clear kind of lecturing it was very easy and interesting to follow. Sometimes i feel sad if my phone shows low battery power during the class time. I hope i could attend almost week exercises well. Demonstrations also very helpful. I spent time for getting better mark by repeating exams when ever my percentage become low. Special thanks to Prof. Dorian Canelas.

By Janay v

Nov 4, 2021

I took the course as a complete beginner. This was my first chemistry course and I enjoyed the professor and her teaching style. I believe this course is best suited for students who possess prior knowledge of chemistry concepts. I would definitely recommend this course to any one who is looking for a challenge. After successfully completely this course, I am very eager to enroll in a chemistry class at my community college.

By Sanni K

Sep 15, 2022

I have not had chemistry for about 12 years but was able to follow the course without any problems in order to review the basic concepts of chemistry. It's really for beginners, but still makes you feel the progress of what you've learned while advancing the class. A good balance between theoretical concepts and stoichiometrical calculation. Thanks!!

By Rohan H

Aug 9, 2018

Quality course. Very basic in material but fabulous to understand nomenclature and other technical necessities. I used it to prepare for a honors chemistry course I am taking in my sophomore year of high school. It, in my opinion, is perfect for that use.

By Lucille G

Aug 20, 2020

helpful course, but advanced problem sets are sometimes much more difficult than concepts shown in video sessions

By Crystal Q T Z

Dec 29, 2017

Clear explanations and an excellent course for beginners. Very slow to begin, but informative and thorough.

By Michael B

Feb 18, 2017

There were some errors in the video playback, one entire lesson near the end seemed like it was skipped.

By Sarah S

Nov 12, 2019

I wish more time was spent going over the mathematical equations and more examples were given.

By Martin L

Feb 13, 2021

The video lectures taught you how to pass the tests and didn't really teach anything well.

By Casey D

Oct 12, 2020

Great review for those who need refreshers and good for newcomers to chemistry!

By David A R

Mar 23, 2023

Good explanations, actiivities and experimental examples.

By Kyla M T D C

Oct 17, 2020

I gained a lot of knowledge with this course.

By M L

Feb 9, 2018

It's a very good course and

clear teaching!


Apr 3, 2021

Well explained course. Thank you.