Descarca de aici http://www.didactic.ro/lectii-chimie-5-formule-chimice-p39748-t0
Câteva linkuri utile:
http://www.chem.wisc.edu/areas/organic/index-chem.htm
http://www.chemguide.co.uk/
http://www.chemicalformula.org/
catalin542000 întreabă: