18:53
Modern Periodic Table
11:05
Periodic Classification of Elements
17:58
Acids Bases and Salts
4:25
Le génie du tableau périodique des éléments de Mendeleïev - Lou Serico
15:13
Matter in Our Surroundings : Characteristics of Particles of Matter
23:13
Defects of Vision and Their Correction
17:08
Allotropes of Carbon
12:23