I am always looking for the online resources to help me with chemistry. I have been paying for www.chegg.com, about $14 a month, but the homework help is about 70% good and 30% awful. There really is no way to know if the content is good unless someone before you has found it to be bad and ranked it with a thumbs down either. So, sometimes when I need help figuring out how to solve an equation, especially for Mastering Chemistry, it backfires. To be clear: I do not use the website to get answers to homework, but for the step-by-step explanation so I actually learn it.
Here are some other sites I have found helpful, please chime in below if you have a great resource for those of us in the pre-med years or beyond.
www.khanacademy.org/ (probably no need to mention)
https://answers.yahoo.com/dir/index?sid=396545227 (I am surprised at how good Yahoo Answers forum is for chemistry)
https://www.youtube.com/user/wbreslyn (Dr. Wayne Breslyn’s Youtube channel = tons of Lewis Structures!)
https://www.youtube.com/user/theprofessorheath (Lots of chemistry explanation videos)
https://www.mathsisfun.com/quadratic-equation-solver.html (I had so much trouble with quadratic equations, this helps check your work)
Help from a real person:
https://tutormatchingservice.com/#/home
http://www.smarthinking.com (A lot of students at my college do not know that our tuition includes 900 minutes of online tutoring per year through this site).