Free Java Applet is a chemistry calculator that balances chemical equations and performs stoichiometry and equilibrium calculations in a spreadsheet format. The software provides a tutorial and a demo can be found on mathshowcase.com.

One of the most impressive features of Free Java Applet is that it's integrated with the periodic table. This means that it can easily compute the molecular weight of all entries. Furthermore, it can also calculate partial pressures and apply the Van der Waals equation.
If you're new to chemistry or struggling with your studies, the tutorial provided by Free Java Applet is a great place to start. It features 26 examples that teach you how to balance chemical equations in a clear and easy-to-understand way.
Overall, if you're in need of a comprehensive chemistry calculator that covers a wide range of topics, Free Java Applet is definitely worth checking out. You can even download a free demo at mathshowcase.com to test it out for yourself.
Version 3.4: now supports vista and win7
Version 3.3: now free