Khan/khan-exercises — pull request #14532 by lionaneesh (2012-02-23 21:08:14+00:00)
Title: Add Limiting Reagent Exercise

The patch adds a limiting reagent exercise including basic equations and proper hints.

for more info visit : [1]

[1] http://www.khanacademy.org/video/stoichiometry--limiting-reagent?topic=chemistry