1740-1793

German chemist whose most important work, Lehre von der Verwandtschaft der Körper (1777-82), addressed, among other issues, chemical affinity. Wenzel believed that substance concentration influenced the attractive forces between elements, and he was able to show that the rate at which a metal dissolves in an acid is proportional to the acid concentration. This was an early recognition that chemical reactivity depends on reactant masses, which was first clearly enunciated by Claude-Louis Berthollet (1803).