The Molecule Calculator (MolCalc) is a small web/server application +Jan Jensen and +I build for teaching purposes and also the subject of an article we just submitted to Journal of Chemical Education about. If you haven't, then please check the Molecule Calculator on;
MolCalc is a web interface that allows anyone to build molecules and calculate molecular properties, easy. MolCalc is designed for teaching as opposed to research - specifically for assignments in which students build their own molecules and estimate their own molecular properties. In the newest version we have switched to JSmol, which results in the system is more stable and actually works on most tablets and phones.
Source, bug reports and feature request can be found on github.com/jensengroup/molcalc.
A new web-server called The Molecule Calculator (MolCalc) is presented. The entry page is a molecular editor (JSmol) for interactive molecule building. The resulting structure can then be used to estimate molecular properties such as heats of formation and other thermodynamic properties, vibrational frequencies and vibrational modes, and molecular orbitals and orbital energies. These properties are computed using the GAMESS program at either the RHF/STO-3G (orbitals and orbital energies) or PM3 level of theory (all other properties) in a matter of seconds or minutes depending on the size of the molecule. The results, though approximate, can help students develop a “chemical intuition” about how molecular structure affects molecular properties, without performing the underlying calculations by hand - a near impossible task for all but the simplest chemical systems.
The article can be found on arXiv; http://arxiv.org/abs/1303.1679
Also watch the introduction video for MolCalc 1.1;
More on the Molecule Calculator: