I have recently started learning chemistry, and I've been reading a GCSE (UK high school level) textbook on the stuff :D
Much of it has been fairly straightforward, though there has been a reoccurring theme that has been bothering me.
I've encountered many instances where the author simply presents a reaction with little explanation, as if to suggest that the reason as to why it would occur is obvious.
Let me give you an example I have come across just today. Ethene in bromine water:
I think to myself, 'why would this happen?'. There are no 'free electrons' that I can see in ethene. OK, bromine is highly reactive, but what will it do? Will it react with H, or C, and how? What about the bromine bond? It's all very uncertain in my mind.
I always try to reduce it to an energy problem. We just want the most stable state, right? But, there are many possible outcomes. Am I supposed to apply some logic, follow some flowchart, or work out all possible outcomes and calculate which has the lowest energy? Do chemists just remember all simple reactions, and reduce problems to those? Or, am I just overthinking it?
A side problem to this is why, if we place an alkane in bromine water, we don't get the same thing happening with ethane.