Working under Wurtz, he explained optical activity in organic molecules independently of Le Bel, and his namesake factor, usually denoted with a lowercase "i," accounts for the dissolution of electrolytes in calculations of osmotic pressure.  
One of this man's namesake equations states d ln [lawn] K by dT equals delta H over R times T squared, and can be used to determine enthalpy of a reaction without a calorimeter. With Ostwald, he established the first journal of physical chemistry.  Working under Wurtz, he explained optical activity in organic molecules independently of Le Bel, and his namesake factor, usually denoted with a lowercase "i," accounts for the dissolution of electrolytes in calculations of osmotic pressure.  FTP, name this scientist, the first winner of the Nobel Prize in Chemistry.
One of this man's namesake equations states d ln [lawn] K by dT equals delta H over R times T squared, and can be used to determine enthalpy of a reaction without a calorimeter.
Jacobus Henricus van't Hoff