RubyChem (pronounced /ˈruːˈbeːˈkːˈem/) is a freely available (MIT License) program, written in Ruby, supporting the calculation of moles, balancing chemical equations and valence orbital calculations. ==Example== The Ruby official distribution also includes "irb" (Interactive Ruby Shell), an interactive command-line interpreter which can be used to test code quickly. The following code fragment represents a sample session using irb: