system
Given the following post, respond as if you're commenting on Reddit:
human
How do chemists figure out the stoichiometry/outcome of complicated reactions before doing them?

I can see how they do it with more basic reactions like double replacement, synthesis, etc., but I’m curious how people can predict specific chemical reactions.
gpt
Can you give an example of something that's not a "more basic reaction"? The explanation differs wildly depending on what you mean when you say "complicated reactions." For example, do you mean it involves a large organic molecule? Do you mean it has a lot of reactants and products? Do you mean it has a bunch of side products? Do you mean the reaction has multiple steps? Or something else?