Quote Originally Posted by Tellenbach View Post
1. Structure of the atom. What's an element? What are the different types of chemical bonding and intermolecular forces (hydrogen, van der waals, covalent bonds (sigma and pi bonds), ionic bonds); Electron configurations and periodicity in the periodic chart.
2. What's a Lewis Acid and Base? What's a Bronsted acid and base?
3. Chemical equilibrium (What's Le Chatelier's principle? How do you balance a chemical reaction?)
4. Kinetics (What's the rate determining step? What's the activation energy? What's a first order and second order reaction? What's a catalyst)
5. Gas Laws (there are a bunch of them)
6. Chemical reactions (how to determine yield and find the limiting reagent; what's a mole? What's a redox reaction?)
7. Thermodynamics (what's entropy, enthalpy, endothermic vs exothermic reactions, how to tell if a reaction is spontaneous)
8. Nomenclature (what are alkanes, alkenes, alkynes, amides, esters, ketones)
9. Biological molecules (what are proteins, carbohydrates, lipids, nucleic acids)

For general chemistry, all you need is some basic algebra and what scientific notation is. I would just get a basic chemistry textbook and start reading.

For some inspiration, go watch Lorenzo's Oil. It's a true story about a banker who learns lipid metabolism (biochemistry) so he can save his son's life.
This is a fantastic list for a beginner to intermediate for sure! Also, as chemistry is the "middle" science, it's one of the most useful, IMO, for everyday tasks--perhaps second to Newtonian Physics.

If the OP wants more, he will need a bit of calculus. But even for this, I don't think he'd need anymore than single variate.

Quote Originally Posted by skylights View Post
There are universities that offer free basic online courses. It may be useful to look into those. The only thing I think you'd be missing out on is the hands on lab experience.
The lab experience is definitely a plus, but as long as someone doesn't plan on becoming a "wet" chemist or physicist, I'd say it's unnecessary.

If the OP can, for example, can match molar quantities, chemistry experiments should be able to be skipped.

Quote Originally Posted by Coriolis View Post
Well, first of all, it's a HeNe laser, short for Helium Neon, and it's not going to burn through anything. Find a CO2 or Ytterbium fiber laser for that.

Second, you should ask yourself why you want to learn science, and what you plan to do with that knowledge. If you want to work in a scientific career some day, the preparation you undertake may be different from what you need if you just want to understand basic science for the pleasure of it, and to be a more educated person.

I know much of what I have written is rather vague, but "science" as a whole is an enormous topic, and I'd prefer to focus on more specific questions, if you have them. Study of science is the activity of a lifetime, especially when you are not constrained by passing the next exam or course, but can follow your interests and go at your own pace. (Rest assured, my judgmental gaze is reserved for those who don't make the effort. I have only encouragement for those who do.)
Are you a physicist?

Have you ever tried to independently learn this stuff?
All the time. In fact, most science majors and students do a lot of self learning. A chem professor I had always said, "Don't let your courses get in the way of your education."With youtube, free books, and edu websites, it's especially true today.

What should I read/watch/listen to?
EDU sites. Youtube. You can literally type in a question or a topic and find good explanations.

Any good websites you can recommend?
Already recommended: khanacademy. Hyperphysics.

Where should I start? What are the key/basic concepts I should try to learn?
In my opinion, students should start from physics. I feel physics teaches you to quickly learn all the sciences. Chemistry itself virtually fell out of Quantum Mechanics. Thermodynamics are better explained by physics, although overlap occurs in Physical Chemistry and Chemical Physics. From understanding basic Newtonian Physics, you can understand a good deal around you.

However, physics is more math heavy than chemistry. BUT it explains the math better. I took several physics courses because they made the math I was doing much more concrete. IMO, Physics I at a university does a better job at teaching calculus than actual calculus courses.

How much math do I need to know (I have a vague memory of 11th grade math)?
Basic Chemistry - Algebra 2
Organic Chemistry - none
Biochemistry - depends. Could be just algebra or up to very in-depth calculus and linear algebra.
Physics - depends. You can do it at an algebraic level, but the calculus versions give you more understanding
Biology - depends. Genetics relies on a good deal of math.

I recommend learning something like Organic Chemistry first if math is the issue. For one, it explains things you're used to seeing in your products everyday.Secondly, it builds spacial intuition, which is useful in all sciences.