Could quantum mechanics replace modern chemistry? Why or why not please, and thank you.

It did that fifty years ago.

QM will not and does not replace (modern) chemistry. Chemistry and QM are not mutually exclusive and in fact QM is an essential part of some (many?) branches of chemistry, notably physical chemistry. As for the question how long that´s been the case already: Not being a chemicist I have little clue, but the 50 years mentioned by Meir Achuz seem reasonable.

As I understand it, it is quite possible to work out the results of chemical reactions using QM, but the maths involved is considerably more complicated than other methods so they are chosen for that reason. In the same way newtonian mechanics can all be calculated using relativity but few people ever do it on a day to day basis.

That is probably true but I am not sure if it correctly reflects what modern chemistry is about; sounds too much like the chemistry you learn in school. I´d think that almost all modern chemistry uses QM methods or results to a lesser (spectroscopy) or greater (density functional theory) degree. Speaking for physics and staying with your example: I spontaneously wouldn´t personally know (from what I know or guess about their work) any physicist who uses Newtonian mechanics on a daily basis while all I know use relativistic calculations to various extends (ranging roughly from solid state physicists who analyze their probes with X-ray over people doing optics to nuclear and particle physicists).

 

EDIT: @next post: That does indeed seem interesting. I´ve already thought about asking a mod to move this thread to some chemistry section hoping to get some information by people more familiar with chemistry, there. So pls tell us what he said about it (or convince him to join sfn and post it here ).

That is probably true but I am not sure if it correctly reflects what modern chemistry is about; sounds too much like the chemistry you learn in school. I´d think that almost all modern chemistry uses QM methods or results to a lesser (spectroscopy) or greater (density functional theory) degree. Speaking for physics and staying with your example: I spontaneously wouldn´t personally know (from what I know or guess about their work) any physicist who uses Newtonian mechanics on a daily basis while all I know use relativistic calculations to various extends (ranging roughly from solid state physicists who analyze their probes with X-ray over people doing optics to nuclear and particle physicists).

 

Yeah that's probably truer to life it was a first year chem undergrad that once said that explination to me, I shall ask him what (now in his 4th year) he thinks...

If anyone can word this better as it seems most the posters get what I am trying to put forward and get more posts as a result on it, feel free to do so. I would like to find out much more on the topic myself.