(1) Concurrency and program analysis are intesting research topics to me.
(2) CS is more thinking-heavy, at least in the subfield that I have stepped in, but chem
is more on experiments and I prefer thinking on my seat than working in the lab.
(3) A very practical reason: averagely a cs graduate can earn more than chem.
(4) CS is safer than chem, because in the worst case, you can crash your PC or
server, but in chem, it's far more serious!