The
spectroscopy tools
A fast and quick online tool to identify what chemical groups belongs to a
spectral range including NMR (1H, 14C), Mass spectroscopy and IR
Metric
System This site
gives you everything that you wanted to know about the Metric System
Chemistry
converter
Very extensive including concentration, diffusivity,
viscosity, enthalpy, entropy, heat transfer coefficients and more
by Process Associates of America