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返回到 化学基础:反应和比率

学生对 杜克大学 提供的 化学基础:反应和比率 的评价和反馈

1,056 个评分


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....



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.


251 - 化学基础:反应和比率 的 273 个评论(共 273 个)

创建者 Michael B

Feb 18, 2017

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

创建者 Sarah S

Nov 12, 2019

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

创建者 Martin L

Feb 13, 2021

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

创建者 Casey D

Oct 12, 2020

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

创建者 Kyla M T D C

Oct 17, 2020

I gained a lot of knowledge with this course.

创建者 M L

Feb 9, 2018

It's a very good course and

clear teaching!


Apr 3, 2021

Well explained course. Thank you.

创建者 Amartya M

Oct 28, 2020

Great course for concept clearance

创建者 廷瑋 王

Jul 17, 2017

clear concept explanation

创建者 Habib U

Oct 11, 2019

helpful for the biginner

创建者 Dr. B D

Nov 17, 2018

I rather enjoyed it. :-)

创建者 Грязев В В

Dec 16, 2016

понятный и доступный

创建者 John F

Jul 1, 2020

a good introduction

创建者 Nafiul A

Jun 17, 2020

I loved this course

创建者 Eb E

Nov 12, 2019

Cool class!

创建者 Nancy L

May 1, 2021

I've found easier tutorials on YouTube for certain subjects but I really enjoyed the demos!

创建者 mohammad o t

Mar 10, 2021

Very long videos

创建者 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.

创建者 Armon A

Jul 25, 2021

The lectures were difficult to follow, and the material on the tests were not covered well.

创建者 Gerald L P

Dec 27, 2021

First of all I am a retired Chemist. I could not get through the first quiz because I believe some of the answers are wrong. I think it better to not frustrate students with "passing" grades. The goal of learning is to learn not to answer questions with only "one" correct answer. 0.01 vs .01 is the same but one would be scored correct and the other wrong. Immediate feedback would be a better way to score quizzes.

创建者 Nicolás C M

Aug 14, 2020

It say introduction, but it is more advanced that it seems

创建者 Lacie C

Dec 7, 2020

Too much at one time.