Reaction is a card game from The Idea Corps whose copy speaks for itself:
Players take turns drawing cards until they can create molecules from the element cards in hand. When a player can build a molecule, they lay it out in front of them on the table. Opponents can add onto the molecule to turn it into a different molecule, or they can destroy it with a Bunsen Burner card.
It appears to be a simple melding-type game, an average card game in its own right, but very interesting because of its theme, since, like Mahjong, you have to know what combinations work for melds, which is also indirectly educational.